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Samira Ahmed (presenter): brickwalled at 17 kHz, as were the LehrerIs this not an MP4 'thing'? If you download a piece of music from
extracts.
(https://www.bbc.co.uk/sounds/play/m002gfzv)
As I wanted the Richard Stilgoe tribute to Tom Lehrer, I've extracted
the audio from this programme. It's nominally MPEG4 AAC, 48 kHz sample
rate (so in theory up to 24 kHz), 320 kbps, stereo.
1. It's definitely mono; my X-Y display is a straight diagonal line.
Apart from the "BBC Sounds" sting in the first four seconds, the
musician at 0:31 to 0:50, the Lehrer recordings at 4:19-4:48 and
6:15-6:39, Cleo Laine 8:10-8:38, and Nick Drake 10:46-11:~11:13, 12:31-12:5x*, and 15:13-15:39*. 17:05-17:27. 22:45-23:02 drama extract.
Maybe this is normal (maybe has been for decades?) - record individual speakers with a mono mic., but mix (really, weight) them so they appear
(only very slightly) at different positions? With the presenter centre.
I wouldn't really have noticed the varying position, but I _am_
listening on a laptop's internal speakers, so that's probably
understandable; I only really noticed when the mono line varied in angle slightly between speakers.
On 28/07/2025 23:15, J. P. Gilliver wrote:Ah, may well be! I will admit I just used y with no parameter (other
Samira Ahmed (presenter): brickwalled at 17 kHz, as were the LehrerIs this not an MP4 'thing'? If you download a piece of music from
extracts.
YouTube with yt-dlp so you can choose the format, the MP4 ones all have
this 17 kHz limit whilst the Opus files don't.
The normal layout for recording these shows is with the participants sat round a table and each has their own microphone. The inserts are added > by the engineer. Quiz shows such as "Have I Got News For You" use a
table for each team and one for the judge and scorer, with a microphone
for each participant. There are photographs and videos available on line which show this. As you have noticed, stereo is simulated by panning the signals left and right in varying proportions. There are very good
reasons for this including room noise and keeping relative levels steady.
On 2025/7/29 19:38:0, John Williamson wrote:
[]
The normal layout for recording these shows is with the participants satBut each participant just collected with a single (mono) mic., which is
round a table and each has their own microphone. The inserts are added
by the engineer. Quiz shows such as "Have I Got News For You" use a
table for each team and one for the judge and scorer, with a microphone
for each participant. There are photographs and videos available on line
which show this. As you have noticed, stereo is simulated by panning the
signals left and right in varying proportions. There are very good
reasons for this including room noise and keeping relative levels steady.
then mixed in fixed proportion to the two channels, with the proportion differing from one speaker to another (presenter usually being 1:1,
i. e. centre). Interesting.>
On 29/07/2025 21:37, J. P. Gilliver wrote:
But each participant just collected with a single (mono) mic., which isIt also means that the vocal bits are 100% mono compatible with none of
then mixed in fixed proportion to the two channels, with the proportion
differing from one speaker to another (presenter usually being 1:1,
i. e. centre). Interesting.>
the phasing effects you would get using, say, a spaced pair.
On 2025/7/29 21:48:34, John Williamson wrote:
On 29/07/2025 21:37, J. P. Gilliver wrote:
[]
But each participant just collected with a single (mono) mic., which isIt also means that the vocal bits are 100% mono compatible with none of
then mixed in fixed proportion to the two channels, with the proportion
differing from one speaker to another (presenter usually being 1:1,
i. e. centre). Interesting.>
the phasing effects you would get using, say, a spaced pair.
Good point I hadn't thought of! Similar to the slight variable-comb
effects used when combining the channels from a stereo pickup playing a
mono record on a non-linear-tracking turntable.
J. P. Gilliver <G6JPG@255soft.uk> wrote:
On 2025/7/29 21:48:34, John Williamson wrote:
It also means that the vocal bits are 100% mono compatible with none of
the phasing effects you would get using, say, a spaced pair.
Good point I hadn't thought of! Similar to the slight variable-comb
effects used when combining the channels from a stereo pickup playing a
mono record on a non-linear-tracking turntable.
...made even worse on early recordings by the recording engineer
twisting the recording stylus to help throw the swarf to one side. The
two 'channels' can be out of step by an amount which depends on how far
up the groove walls the elliptical playback stylus makes contact, so
even a parallel-tracker won't play them correctly unless the cartridge
is mounted on a swivel and can be offset to the correct angle.
At about 8 Kc/s, the HMV frequency test record can give almost purely circular movement to the stylus tip; the two groove walls are 90-degrees
out of phase with a 0025" radius elliptical stylus mounted orthogonally.
On 2025/7/30 8:31:10, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
On 2025/7/29 21:48:34, John Williamson wrote:
[]
It also means that the vocal bits are 100% mono compatible with none of >>> the phasing effects you would get using, say, a spaced pair.
Good point I hadn't thought of! Similar to the slight variable-comb
effects used when combining the channels from a stereo pickup playing a
mono record on a non-linear-tracking turntable.
...made even worse on early recordings by the recording engineer
twisting the recording stylus to help throw the swarf to one side. The
I wasn't aware of that!
two 'channels' can be out of step by an amount which depends on how far
up the groove walls the elliptical playback stylus makes contact, so
even a parallel-tracker won't play them correctly unless the cartridge
is mounted on a swivel and can be offset to the correct angle.
(Which mine - Marantz TT520 - certainly isn't.)>
At about 8 Kc/s, the HMV frequency test record can give almost purely circular movement to the stylus tip; the two groove walls are 90-degrees out of phase with a 0025" radius elliptical stylus mounted orthogonally.
I presume that's a test record made before stereo? (What date _is_ it,
and what frequencies does it contain [assuming it has tones or a sweep],
out of interest?)
J. P. Gilliver <G6JPG@255soft.uk> wrote:[]
So 8.6 k (strange number!) was the highest it was thought worth worryingI presume that's a test record made before stereo? (What date _is_ it,>> and what frequencies does it contain [assuming it has tones or a sweep],
out of interest?)
One side of HMV DB4037 is a set of bands at different frequencies with> the highest, 8.6 Kc/s, on the outside to take advantage of the higher
surface speed. There are other sides in the set with fixed and sweep
tones, but none above 8.6 Kc/s. It was monophonic and was cut in 1936> with the Blumlein mono cutterhead, which had a particular problem with
'azimuth' offset. They were all recorded with a 'U'-bottomed groove,
which needs a truncated elliptical playback stylus for the best results> - and that is the type most affected by theoffset.
The Blumlein cutterhead had the cutting tip hung on the end of a
trailing cantilever which was swung from side to side by rotary movement
of a near-vertical shaft. If there was any misalignment of the cutting> face, the force it generated by throwing the swarf off to one side would
push it sideways and cause an even bigger misalignment. Because the restoring springs on the vertical shaft were not very stiff (to achieve> the correct resonant frequency), this misalignment could be quite
considerable.
Another problem caused by the compliance of the springs was that the
rush of air into the suction pipe (which was fitted to remove the swarf)
had to be limited in order to prevent it disturbing the cutter; on
Columbia DX73 this is very obvious as a constant roaring background
noise. I imagine the operator would have been very tempted to
deliberately skew the cutter to aid swarf removal - although I have no
proof of that, other than a large number of discs recorded with the
Blumlein cutter which have considerable 'azimuth' errors.
On 2025/7/30 16:49:55, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[]
I presume that's a test record made before stereo? (What date _is_ it,
and what frequencies does it contain [assuming it has tones or a sweep], >> out of interest?)
One side of HMV DB4037 is a set of bands at different frequencies with
the highest, 8.6 Kc/s, on the outside to take advantage of the higher surface speed. There are other sides in the set with fixed and sweep tones, but none above 8.6 Kc/s. It was monophonic and was cut in 1936 with the Blumlein mono cutterhead, which had a particular problem with 'azimuth' offset. They were all recorded with a 'U'-bottomed groove,
which needs a truncated elliptical playback stylus for the best results
- and that is the type most affected by theoffset.
So 8.6 k (strange number!) was the highest it was thought worth worrying about in 1936. Interesting. (Do you have a chart of what was considered
a reasonablr bandwidth at various dates?) I'd have thought that rather
low for 1936, though couldn't justify that feeling if challenged.>
J. P. Gilliver <G6JPG@255soft.uk> wrote:
So 8.6 k (strange number!) was the highest it was thought worth worrying
about in 1936. Interesting. (Do you have a chart of what was considered
a reasonablr bandwidth at various dates?) I'd have thought that rather
low for 1936, though couldn't justify that feeling if challenged.>
I think it was sufficient to cover the top resonance of the pickups of
the day, which was a major concern - and, yes, it was probably the
highest frequency they could sensibly record with the equipment they had
at EMI at that date. Higher frequencies than that were recorded by
slowing down the recording lathe, but this wasn't normal practice.
It wasn't until Arthur Haddy of Decca produced the FFRR recording system
that higher frequencies were recorded on commercial records (which made
Mantovani's strings famous). Haddy's cutterhead was copied from Voigts
moving coil design without acknowledgement; when Sugden later copied it
from Haddy, Haddy was furious but couldn't do anything about it.
For a much fuller explanation look at Peter Copeland's "Manual of
Analogue Audio Resoration Techniques". It is supposed to be on the
British Library's website but the page has vanished so you may have to download an archive copy. [That should keep you busy until I come back
from holiday.]
On 2025/7/31 9:15:20, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[]
So 8.6 k (strange number!) was the highest it was thought worth worrying >> about in 1936. Interesting. (Do you have a chart of what was considered
a reasonablr bandwidth at various dates?) I'd have thought that rather
low for 1936, though couldn't justify that feeling if challenged.>
I think it was sufficient to cover the top resonance of the pickups of
the day, which was a major concern - and, yes, it was probably the
Ah yes, that's something (probably one of many!) I hadn't thought of.
If that _was_ a major concern, did (the more expensive - which probably includes _all_ electronic ones in those days) systems (record player
would be part of same piece of furniture as amplifier) contain a notch,
or at least a low-pass filter, to cover the mentioned resonance? (I
doubt it - certainly never heard any mention.)
slowing down the recording lathe, but this wasn't normal practice.
Wasn't that technique re-visited by some of the labels associated with
high quality, in the '70s-'90s? Like maybe Deutsche Grammophon, Telarc..>
It wasn't until Arthur Haddy of Decca produced the FFRR recording system that higher frequencies were recorded on commercial records (which made
I hadn't realised that was an actual thing, rather than just marketing.
(FFRR for me - Flanders & Swann, "Song of Reproduction", 1959-5-2: https://www.youtube.com/watch?v=EL5SzTSMxLU.)
Mantovani's strings famous). Haddy's cutterhead was copied from Voigts
Didn't Mantovani also sneak in a bit of double (or more) tracking?
moving coil design without acknowledgement; when Sugden later copied it from Haddy, Haddy was furious but couldn't do anything about it.
For a much fuller explanation look at Peter Copeland's "Manual of
Analogue Audio Resoration Techniques". It is supposed to be on the
British Library's website but the page has vanished so you may have to download an archive copy. [That should keep you busy until I come back from holiday.]
Ah, once I'd put the missing t in, Google found it for me: <https://cool.culturalheritage.org/byform/mailing-lists/arsclist/2008/09/m sg00144.html#:~:text=Peter%20Copeland%2C%20Conservation%20Manager%20at,tec hnicians%20working%20in%20digitisation%20programmes.>Oh. 404 from the link there.
But the link on
<https://www.vintage-radio.net/forum/showthread.php?t=165910> works,
today anyway! Got it.Have a good holiday!
J. P. Gilliver <G6JPG@255soft.uk> wrote:
On 2025/7/31 9:15:20, Liz Tuddenham wrote:
I think it was sufficient to cover the top resonance of the pickups of
the day, which was a major concern - and, yes, it was probably the
Ah yes, that's something (probably one of many!) I hadn't thought of.
If that _was_ a major concern, did (the more expensive - which probably
includes _all_ electronic ones in those days) systems (record player
would be part of same piece of furniture as amplifier) contain a notch,
or at least a low-pass filter, to cover the mentioned resonance? (I
doubt it - certainly never heard any mention.)
The real problems were:
1) Harshness because scratch was emphasised by the top resonance. This
was dealt with by providing a tone control. Yes, you lost the treble
from the music, but 'mellowness' was much prized in those days. Tuning
it out was occasionally used in professional equipment where the
resonances were accurately known and controlled, but this was too sophisticated for domestic equipment.
2) The mechanical resonance increased the effective stiffness of the
needle at certain frequencies and caused damage to the record. You
often come across records with 'blasting' distortion on certain notes,
cause by the damage to the grooves where they were previously played on something with bad resonances.
[...]
slowing down the recording lathe, but this wasn't normal practice.
Wasn't that technique re-visited by some of the labels associated with
high quality, in the '70s-'90s? Like maybe Deutsche Grammophon, Telarc..>
Yes, it could be used on 'programme' material once tape had come into
use for mastering, but in the 1930's there was no way of slowing down
the performance, which had to be transferred to the wax in real time.
Only things like frequnecy test records could take advantage of it.
The exception to this was the Path|- company, which mastered their performances on large high-speed wax cylinders and then transferred them
to a master disc with a pantograph system (called a "poisson", because
it looked like a fish). The ratio of the pantograph could be varied to increase or decrease the volume on the final disc. It had too much mass
to vibrate at the higher audio frequencies, so the cylinder and the disc
were both slowed down to do the transfer at reduced speed.
The story goes that the transfer machines were located on the top floor
of the building and powered by weight motors. During the working day,
the weights, which were suspended from crane arms outside the building, gradually descended into the street and had to be wound up before they reached head level of the passers-by.
It wasn't until Arthur Haddy of Decca produced the FFRR recording system >>> that higher frequencies were recorded on commercial records (which made
I hadn't realised that was an actual thing, rather than just marketing.
It became a marketing slogan some time after WWII, but it was originally developed for training wartime ASDIC operators to distinguish between
the sounds of different ships. Some records can be found with FFRR characteristics but with nothing on the label to distnguish them from
the standard Decca recordings.
The changeover occurred shortly after the release of the film "The Third Man". The recording of "The Harry Lime Theme" was an incredibly
successful best-seller. At some point there was a disaster and the
Peter Copeland and I spotted this when going through piles of thousands
of old records in the back of a shop. After seeing several dozen copies
of the "Harry Lime Theme" that had come from the first master, I came
across one that didn't quite look the same as the others. Peter
identified it as an FFRR recording and pieced together what must have happened.
For a much fuller explanation look at Peter Copeland's "Manual of
Analogue Audio Resoration Techniques". It is supposed to be on the
But the link on
<https://www.vintage-radio.net/forum/showthread.php?t=165910> works,
today anyway! Got it.Have a good holiday!
Back from holiday now - but I bet you won't have finished reading that
tome of information.
Yes - until big speakers became commoner, bass response was hard to
obtain,
...(I remember Gerry the museum demonstrating an
entirely mechanical gramophone that actually sounded pretty good - I
don't remember it _specifically_ having a lot of base, but it certainly sounded as good as mid-fi electronic kit - but that was a unit intended
for things like village halls that didn't have electricity, and had a
horn two or three feet across.)
The exception to this was the Path|- company, which mastered their performances on large high-speed wax cylinders and then transferred them
Presumably nobody else did that due to a patent or something?
Some records can be found with FFRR
characteristics but with nothing on the label to distnguish them from
the standard Decca recordings.
So what was actually different? I presume it had a higher bandwidth, but presumably with the same equalisation to non-FFRR records (otherwise
you'd need a switchover control in the player and I've never seen one).
Was there something specific that gave the extra top - something in the recording electronics? Some more-than-just-incremental improvement in
the cutter heads?
The changeover occurred shortly after the release of the film "The Third Man". The recording of "The Harry Lime Theme" was an incredibly
successful best-seller.
I'm not surprised: it's a definite earworm.
How do you identify an FFRR recording - just because it has more top?
In the last few days, I've been working on[...]
de-Kindling "The Oxford Dictionary of Family Names in Britain and
Ireland",
I'll probably use less than the Copeland
book, but it had to be done!
(Is he any relation to Aaron the composer? It's not a common name, I
think.)
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[...]
Yes - until big speakers became commoner, bass response was hard to
obtain,
When the Western Electric recording system first came in, there was a
problem which they disguised with salesmanship. The whole system was
based on 'matched impedances', using the theory that the components of a mechanical 'circuit' are equivalent to those of an electrical circuit
and can be analysed with the same formulae. Bell Labs had used matched impedances to optimise the telephone system and WE (their manufacturing division) attempted to do the same for sound recording.
Unfortunately there is no convenient mechanical equivalent of a
resistor, so the damping of the vibrating armature in the cutter system
was done by terminating it with an 'infinite line' (actually only about
a foot long) which consisted of a torsion strip of metal in a casing
A badly-adjusted line gave rise to a honk in the bass response, which
sounded like poor studio acoustics. It was impossible to see from the
disc whether this fault had cropped up, so it was only discovered when
the first test pressings came back from the factory - by which time a
number of poor recordings had been made.
HMV turned this into a 'feature' with the advertising slogan "Listen toIngenious!
the Bass ! " Some of their moving coil speakers were, indeed,
excellent. They had a cloth surround and a huge magnet powered by using
it as the HT smoothing choke. I know from experience that if you got a
pair of pliers stuck to the pole piece, you could not pull it free and
had to turn off the power first.
...(I remember Gerry the museum demonstrating an
entirely mechanical gramophone that actually sounded pretty good - I
don't remember it _specifically_ having a lot of base, but it certainly
sounded as good as mid-fi electronic kit - but that was a unit intended
for things like village halls that didn't have electricity, and had a
horn two or three feet across.)
Probably one of the EMG products. They are highly prized and can give
really good sound quality if the sound box is correctly adjusted.
Norman White, of Nimbus Records, went even better and built one that
filled the grand hall of a castle.
[...]
The exception to this was the Path|a-- company, which mastered their
performances on large high-speed wax cylinders and then transferred them
Presumably nobody else did that due to a patent or something?
Actually it was the other way around. The system of duplicating mothers
and stampers from a 'master' disc was patented but there was nothing to
stop Path|- duplicating individual disc stampers by dubbing from a master cylinder. Also, it was a French invention, therefore nobody else wanted
to try it.
So what was actually different? I presume it had a higher bandwidth, but
presumably with the same equalisation to non-FFRR records (otherwise
you'd need a switchover control in the player and I've never seen one).
There were much higher frequencies recorded and the stronger magnet of
the FFRR cutterhead also allowed a higher overall amplitude to be
recorded without running into distortion. The FFRR recording
characteristic was definitely different, with HF pre-emphasis and a
lower mid-turnover frequency, but the characteristics of domestic
players of the day were so approximate that it really wasn't noticed
among all the other distortions. Professional transcription engineers nowadays do have to be aware of the difference and make sure they use
the correct characteristic.
A further complication is that the surface of the blank disc may not be
flat, so the cutter has to maintain an even groove depth on an
undulating surface. A big heavy magnet, however well counterbalanced,
is not going to move up and down at 2 cycles per rev at 78 rpm without considerable accelerating forces, so Haddy (learning from Voigt) fixed
the magnet and allowed the coil to float up and down in the magnet air
gap on a lightweight pivoted frame.
This meant the magnet then had to produce an homogenous field over the greater area of an air gap made large enough to allow the coil to float
up and down without running into a weak field area. The electromagnet
which Haddy used to achive this was gigantic and had to be suspended
from the ceiling by a hawser running over pulleys, with a counterbalance weight in the corner of the room. The power supply filled a complete
floor-standing 21" rack, with a variac to regulate the current.
Whilst they were almost unknown to amateurs, large audio amplifiers
(often using transmitting triodes) were easily obtained or built by professionals, so it was no problem to drive the coil with whatever
power was needed. Pre-emphasis had always been limited by the
cutterhead, not by the amplifier. (Early HMVs had a cavity resonance in
the microphone that gave mild top boost. They denied it for years until Voigt published a proof which they could not dispute.)
version of the slow theme that is played in the final scene of the film
where Anna walks straight past Martins. (That was a re-write of the
happy ending which the original plot had intended.) That scene is the
visual equivalent of an earworm and still haunts me.
[...]
How do you identify an FFRR recording - just because it has more top?
In that particular case it looked 'rougher' and more sparkly than the pre-FFRR recordings. Usually you won't have two different recordings to
compare, so you begin by suspecting that any Decca from that era might
turn out to be FFRR. As above, you may be able to see a difference (if
In the last few days, I've been working on[...]
de-Kindling "The Oxford Dictionary of Family Names in Britain and
Ireland",
I'll probably use less than the Copeland
book, but it had to be done!
Yes, so much of my work is in that category.
(I am enjoying this chat - feel free to take it to email, but I think
it's on-topic to some extent for UTB, and I hope others are enjoying it
too.)
Unfortunately there is no convenient mechanical equivalent of a
resistor, so the damping of the vibrating armature in the cutter system
Isn't that what shock-absorbers in car suspension do? Though I can see
that they're not going to be transferrable to smaller amplitudes and
higher frequencies.
was done by terminating it with an 'infinite line' (actually only about
a foot long) which consisted of a torsion strip of metal in a casing
[]
A badly-adjusted line gave rise to a honk in the bass response, which sounded like poor studio acoustics. It was impossible to see from the
disc whether this fault had cropped up, so it was only discovered when
the first test pressings came back from the factory - by which time a number of poor recordings had been made.
When you say "see from the disc" you mean physically looking at it, I presume, as I guess they couldn't be actually played?
What they'd have given for digital signal processing to damp resonances!
(I worked in that area briefly.) Though pre-digital - analogue -
electronics maybe _could_ manage some of it - but couldn't be _adaptive_
like digital can. (I don't suppose any such is used by any record-making companies now, as it came along too late.)
a huge magnet powered by using
it as the HT smoothing choke.
Ingenious!
...(I remember Gerry the museum demonstrating an
entirely mechanical gramophone that actually sounded pretty good - I
don't remember it _specifically_ having a lot of base, but it certainly
sounded as good as mid-fi electronic kit - but that was a unit intended
for things like village halls that didn't have electricity, and had a
horn two or three feet across.)
Probably one of the EMG products. They are highly prized and can give really good sound quality if the sound box is correctly adjusted.
Norman White, of Nimbus Records, went even better and built one that
filled the grand hall of a castle.
I remember the horn was of some fibrous material, certainly not metal.
Did you ever visit Dulwich while Gerry was alive? (Last time I looked
the museum was still in operation, but wouldn't be the same without
Gerry - though probably still worth a visit.)
The system of duplicating mothers
and stampers from a 'master' disc was patented but there was nothing to stop Path|- duplicating individual disc stampers by dubbing from a master cylinder. Also, it was a French invention, therefore nobody else wanted
When you say stampers from a master cylinder, I presume via an
intermediate master?
I've never heard of anyone directly cutting a
stamper (making ridges rather than grooves) - did anyone?
Ah, like Something Essentially Contrary to the American Method (coming
as it did between Never Twice Same Colo[u]r and Peace At Last).
So what was actually different? I presume it had a higher bandwidth, but >> presumably with the same equalisation to non-FFRR records (otherwise
you'd need a switchover control in the player and I've never seen one).
There were much higher frequencies recorded and the stronger magnet of
the FFRR cutterhead also allowed a higher overall amplitude to be
recorded without running into distortion. The FFRR recording
I was just wondering if there was some definite change. Sounds (!) as if
it was just incremental development though. Or was it the use of an electromagnet rather than a permanent magnet that was the difference?
characteristic was definitely different, with HF pre-emphasis and a
lower mid-turnover frequency, but the characteristics of domestic
players of the day were so approximate that it really wasn't noticed
among all the other distortions. Professional transcription engineers nowadays do have to be aware of the difference and make sure they use
the correct characteristic.
The ffrr logo disappeared though; was that because everyone was
eventually using something equivalent (with tweaks to get around patents
if it actually had any), or just gradual improvements meaning non-ffrr
had caught up (in amplitude and bandwidth)?
[]
A further complication is that the surface of the blank disc may not be flat, so the cutter has to maintain an even groove depth on an
That had definitely never occurred to me; I'm surprised. (I hadn't even thought about it, but surely it would have been possible to skim them or something before starting a recording?)
Earlier-generation (and entirely mechanical) solutions to the tracking
the head in a CD player has to do (the mechanical tolerances allowed -
both laterally [mis-centring] and vertically [warp and bad clamping] -
are eye-watering compared to the "groove" dimensions. When applied at
the 52x speed such players got up to by the end of that era ...)
The power supply filled a complete
Wow ...
floor-standing 21" rack, with a variac to regulate the current.
... and wow.
Whilst they were almost unknown to amateurs, large audio amplifiers
When you say amateurs, do you just mean people who liked loud music,
or
were there amateur record-cutters? (I know there were those "cut a
record" booths, but I gather they were pretty grotty, probably mainly
due to more or less total lack of maintenance.)
[...]
How do you identify an FFRR recording - just because it has more top?
In that particular case it looked 'rougher' and more sparkly than the pre-FFRR recordings. Usually you won't have two different recordings to
You mean the physical appearance of the disc?
Did dynamic groove spacing ever get used on 78s? I presume it'd have to involve recording from a master, so probably had to wait for tape (and
also the electronics), but tape and 78s _did_ overlap.
(Thinking about it, presumably the "direct metal mastering" fad - 1970s,
I think, where they recorded live to cutterhead, claiming the
elimination of intermediate tape improved the quality - _didn't_ use it,
as it couldn't.)
I notice the earliest Tom Lehrer disc (I think the 10 inch one) - which
were issued by Decca in the UK - was definitely far from FFRR:
noticeably limited! Added to the charm, in some ways. (It has recently
come to light - or, at least, to my knowledge - that his recordings were entirely self-organised, he alleges because none of the record companies
he approached would dare to handle the material.)
J. P. Gilliver <G6JPG@255soft.uk> wrote:
(I am enjoying this chat - feel free to take it to email, but I think
it's on-topic to some extent for UTB, and I hope others are enjoying it
too.)
I wouldn't want to trade too strongly on the group's well-known
reluctance to complain....
J. P. Gilliver <G6JPG@255soft.uk> wrote:
What they'd have given for digital signal processing to damp resonances!
(I worked in that area briefly.) Though pre-digital - analogue -
electronics maybe _could_ manage some of it - but couldn't be _adaptive_
like digital can. (I don't suppose any such is used by any record-making
companies now, as it came along too late.)
Amazingly the earliest WE moving coil cutterheads, which cut the vertially-modulated film sound-track records, used electronic damping,
with a velocity-sensing coil in the centre of the drive coil. They
sensing coil to pick up the drive coil field above a certain frequency,
so measurements made using the sensing coil voltage showed an almost
perfect frequency response when, in reality, they were just using the
two coils as a transformer and not measuring the cutter movement at all.
That explained why the shape of the shading ring was critical, it was
meant to fail at higher frequencies so as to 'fiddle' the results.
When I had completed this research, Peter Copeland let on that he had suspected this was the case all along but he needed independent proof -
which was why he had commissioned me to make a cutterhead without
telling me the real reasons behind it. I had thought it very odd that
part of my brief was that I must not attempt to make a direct copy of
any existing cutterhead, now I understand why.
Probably one of the EMG products. They are highly prized and can give
really good sound quality if the sound box is correctly adjusted.
I remember the horn was of some fibrous material, certainly not metal.
It was a mixture of papier mach|- and appliqu|- made from sugar bags and
old telephone directories. They were decorated and then heavily
varnished to make them waterproof. Over the years. many of these horns
have developed a pronounce droop. They are still being made by
enthusiasts (search on YouTube for "Neo-Balmain".)
Did you ever visit Dulwich while Gerry was alive? (Last time I looked
the museum was still in operation, but wouldn't be the same without
Gerry - though probably still worth a visit.)
I never met him but I think the CLPGS arranges visits from time to time.
The biggest change was the wartime necessity to record higher
frequencies which left Decca with a nice piece of kit when peace
returned.
characteristic was definitely different, with HF pre-emphasis and a
lower mid-turnover frequency, but the characteristics of domestic
When the RIAA curve became standard after1954, everyone agreed on one characteristic and Decca fell in with the rest, so although theirYes, I've seen it used - sort of in jest - on some modern releases. (I
records covered the full frequency range, they were no longer to the
FFRR standard. By then, every company had its own way of achieving the
RIAA standard or just bought kit from specialised manufacturers. The difference between RIAA and FFRR was not as noticeable to the public as
the wider frequency range which they both gave. FFRR was (and still is)
a registered trademark, even though it has lost its original meaning.
thought about it, but surely it would have been possible to skim them or
something before starting a recording?)
That was usually done with wax masters but, by the time Decca invented
the FFRR cutterhead, they were using nitrate-on-aluminium blanks which
could not be skimmed. We know they were doing that because aluminium
blanks had one or three drive-pin holes, in addition to the centre hole; these had to be stopped-up before the master could be plated (otherwise
they would have plated-through and prevented later separation of the
plating from the surface of the master). If you look at the label of a
Decca recorded around that time, you can see three ripples where the
stopping was put in and smoothed over.
[...]
Earlier-generation (and entirely mechanical) solutions to the tracking
the head in a CD player has to do (the mechanical tolerances allowed -
both laterally [mis-centring] and vertically [warp and bad clamping] -
are eye-watering compared to the "groove" dimensions. When applied at
the 52x speed such players got up to by the end of that era ...)
CD players never cease to amaze me.
Whilst they were almost unknown to amateurs, large audio amplifiers
When you say amateurs, do you just mean people who liked loud music,
No, most loudspeakers were so efficient over a limited frequency range
that 5 watts was considered far too loud. Battery portable 'picnic'
sets sometimes gave rise to complaints about noise with their 500 mW
Amateur and semi-pro recording machines abounded between the end of WWII
and the introduction of tape. Look at the adverts in Wireless World for
all the different makes. Most of that equipment got by on 10 watts or
less, but the frequency range and amplitude were somewhat limited. A recording machine was a big capital investment for a small music shop or local radio dealer. By comparison, the cost of building a no-compromise recording system was trivial compared with the investment in other plant which the big record companies had to make.
The pre-war record booths produced some excellent recordings but the
post-war ones were ill-thought-out rubbish.
Did dynamic groove spacing ever get used on 78s? I presume it'd have to
involve recording from a master, so probably had to wait for tape (and
also the electronics), but tape and 78s _did_ overlap.
I don't know of any 78s that used an automated system, the groove pitch
was usually set up at the start and stayed constant throughout. I
believe there were a very few recordings made on 78s where the pitch was varied manually in order to get a long recording onto one side of a disc
but I have forgotten the details.
I notice the earliest Tom Lehrer disc (I think the 10 inch one) - which
were issued by Decca in the UK - was definitely far from FFRR:
noticeably limited! Added to the charm, in some ways. (It has recently
come to light - or, at least, to my knowledge - that his recordings were
entirely self-organised, he alleges because none of the record companies
he approached would dare to handle the material.)
There are many links in the recording chain and the weakest one sets the overall limit. If he got his mate with a domestic tape recorder to
record the show, you wouldn't expect better quality, no matter how good
the cutterhead and amplifiers.
When I had completed this research, Peter Copeland let on that he had suspected this was the case all along but he needed independent proof - which was why he had commissioned me to make a cutterhead without
telling me the real reasons behind it. I had thought it very odd that
part of my brief was that I must not attempt to make a direct copy of
any existing cutterhead, now I understand why.
That must have been very difficult too - you must have wondered _why_
you were, presumably, having to design from first principles. Very
difficult to do, I imagine!
[]
Probably one of the EMG products. They are highly prized and can give >>> really good sound quality if the sound box is correctly adjusted.
I was certainly impressed. He also used a fibre "needle" (Flanders &
Swann again!), which he prepared/trimmed before the demo with some small tool, bit like a nail clipper I think.
[]
I remember the horn was of some fibrous material, certainly not metal.
It was a mixture of papier mach|- and appliqu|- made from sugar bags and old telephone directories. They were decorated and then heavily
varnished to make them waterproof. Over the years. many of these horns have developed a pronounce droop. They are still being made by
enthusiasts (search on YouTube for "Neo-Balmain".)
The supply of old telephone directories must be drying up (-:!>
The biggest change was the wartime necessity to record higher
frequencies which left Decca with a nice piece of kit when peace
returned.
So FFRR wasn't a _specific_ equipment change, just a general improvement (partly under wartime secrecy) ...>
thought about it, but surely it would have been possible to skim them or >> something before starting a recording?)
That was usually done with wax masters but, by the time Decca invented
the FFRR cutterhead, they were using nitrate-on-aluminium blanks which could not be skimmed. We know they were doing that because aluminium
Ah, I see (the nitrate coating being thinner than the possible warp in
the aluminium). [Given that it was coated with nitrate anyway so
shouldn't have rusted, wouldn't steel have been both cheaper and less
likely to warp? Though I suppose the cost of aluminium sank into insignificance compared to all the other costs involved.)
the leaflet that came with it stated its
output as something like 65 or 75 MW - I remember being amused at that
rather than mW.
By comparison, the cost of building a no-compromise
recording system was trivial compared with the investment in other plant which the big record companies had to make.
Yes, I imagine a pressing machine - and the material-handling and
-processing needed to feed it - cost a pretty penny.
The pre-war record booths produced some excellent recordings but the post-war ones were ill-thought-out rubbish.
(Weren't some of them modified from speak-your-weight machines?)
[]
. I
believe there were a very few recordings made on 78s where the pitch was varied manually in order to get a long recording onto one side of a disc but I have forgotten the details.
So that would be where it was _known_ - either because it _was_ being
made from an already-existing recording (tape or disc), or from the
score - that there were loud and quiet bits, and where they were.
I remember - I think especially late '70s/early '80s, but maybe longer
period [it could only be after low-playing-weight cartridges] - a
fashion for _very_ low spacing LPs, such that the records had a slightly
oily look from certain angles, due to the grooves being so close
together they operated as a diffraction grating. Low amplitude used to
get a _very_ long time on the side of an LP.
why sell one CD when they can
sell four.
I notice the earliest Tom Lehrer disc (I think the 10 inch one) - which
were issued by Decca in the UK - was definitely far from FFRR:
noticeably limited! Added to the charm, in some ways. (It has recently
come to light - or, at least, to my knowledge - that his recordings were >> entirely self-organised, he alleges because none of the record companies >> he approached would dare to handle the material.)
There are many links in the recording chain and the weakest one sets the overall limit. If he got his mate with a domestic tape recorder to
record the show, you wouldn't expect better quality, no matter how good
the cutterhead and amplifiers.
No, he did go to a recording studio. The record I'm thinking of wasn't
with audience.>
It would have been done from the score and I believe it was considered a
bit experimental at the time. Some lathes used a variable ratio drive
with a rubber tyre running on a disc that could be varied smoothly while
it was recording. others used a small gearbox, where the ratio was
selected by engaging an idler gear or by sliding a cluster along a
splined shaft.
I remember - I think especially late '70s/early '80s, but maybe longer
period [it could only be after low-playing-weight cartridges] - a
fashion for _very_ low spacing LPs, such that the records had a slightly
oily look from certain angles, due to the grooves being so close
together they operated as a diffraction grating. Low amplitude used to
get a _very_ long time on the side of an LP.
It is more likley the high frequencies that gave the diffraction grating
effect. Edison produced LPs that ran for 20 minutes, back in the 1920s,
they are very rare but a friend played me one on an acoustic Edison
machine and it sounded quite good.
[...]
why sell one CD when they can
sell four.
Now you are thinking like a record company.....
No, he did go to a recording studio. The record I'm thinking of wasn'tI notice the earliest Tom Lehrer disc (I think the 10 inch one) - which >>>> were issued by Decca in the UK - was definitely far from FFRR:
noticeably limited! Added to the charm, in some ways. (It has recently >>>> come to light - or, at least, to my knowledge - that his recordings were >>>> entirely self-organised, he alleges because none of the record companies >>>> he approached would dare to handle the material.)
There are many links in the recording chain and the weakest one sets the >>> overall limit. If he got his mate with a domestic tape recorder to
record the show, you wouldn't expect better quality, no matter how good
the cutterhead and amplifiers.
with audience.>
That's a pretty poor show if it was done by a professional. I don't
think Decca would have passed anything sub-standard unless nothing
better could be recovered from the original.
Some lathes used a variable ratio drive
with a rubber tyre running on a disc that could be varied smoothly while
it was recording. [...]
Mention of a rubber tyre running on the disc reminds me - I've only seen pictures - of early experiments with constant linear, as opposed to
angular, velocity. Never caught on, presumably due to the mechanical copmplexity.
[At the other extreme: the _loudest_ record I ever came across was a
single of Engelbert Humperdinck (Roy Dorsey, not the composer!) singing
There Goes My Everything, or its B side, I can't remember. Other than
test discs that is.]
effect. Edison produced LPs that ran for 20 minutes, back in the 1920s, they are very rare but a friend played me one on an acoustic Edison
machine and it sounded quite good.
Needing low playing weights - and fibre needles - if they were to last
at all, I presume.>
J. P. Gilliver <G6JPG@255soft.uk> wrote:[]
With presumably something at the recording (cutting) end. Probably lesspictures - of early experiments with constant linear, as opposed to
angular, velocity. Never caught on, presumably due to the mechanical
copmplexity.
There were several variants of the idea. The gramophone's normal
friction governor was made ineffective by turning it up to full speed,
then the surface speed of the disc was controlled by a small
three-weight centrifugal governor mounted on the sound box and running
on a rubber tyre in contact with the disc surface at the radius of reproduction.
An even cleverer variant of this was a clandestine recorder made forThose stores must be full of many weird and wonderful things!
W.H. Preece of the Post Office (probabably designed by Auguste Stroh).
It recorded a wax disc by means of a fixed cutter on the top side of the
disc and a fixed drive tyre exactly underneath it, bearing on the
underside of the disc. The disc was tracked sideways by a leadscrew mechanism to give a spiral groove.
The whole thing was disguised as a pigeon carrier box and carried on a leather strap over the shoulder. Playback was through a stethoscope and
it could record for more than 10 minutes. I saw the only known exampleWow! in the back store of the Science Museum a few years ago.
There was a famous LP of 1812 Overture where the cannon shots wereThe 1812 is always difficult to do properly: it _does_ sound best with a
visible with the naked eye. The varigroove system spaced the grooves
well away on each side to allow the full amplitude. It was notorious
for throwing the stylus across the record if the playback system wasn't> well designed.
A good test for parallel-tracking mechanisms (or suspect pickup arms) isThere should be a society for the prevention of cruelty to machinery! (Actually, wouldn't that tend to trigger the auto-lift, that detects the
to put on a 45 rpm 'single' with a knocked-out centre, as eccentric as
it will go - then play it at 78 rpm. If it doesn't track properly, a re-design is called for. (Turn down the volume for this test.)
Ah, I'd forgotten that Edison kept their hill-and-dale into the disc era.> stylus pressure had to be high in order to prevent slew-rate-limiting oneffect. Edison produced LPs that ran for 20 minutes, back in the 1920s, >>> they are very rare but a friend played me one on an acoustic Edison
machine and it sounded quite good.
Needing low playing weights - and fibre needles - if they were to last>> at all, I presume.>
No, Edison used a diamond playback stylus and a very hard 'condensate' material (like Bakelite) for the disc, a combination which gave a low coefficient of friction. As the recording was vertically-modulated, the
the 'downhill' slopes of the modulation.
Vertical slew rate:
Some of the most popular cartridges for general transcription work are
the Shure series, they are robust and free of any apparent vices, thereAnd IIRR the range included some that were fairly good but affordable.
is also a good range of styli available from Expert Stylus Co. However, another 78s transcriptor and I both noticed that a sharp notch filter
at around 7 Kc/s noticeably reduced the apparent intensity of the
crackle from bad record material.
It appears that this is due to the sharp-edged particles in the mixture> giving a vertically-downwards 'cliff edge' that leaves the stylus
hanging in space. With nothing to support the free end, the stylus barSort of like a ski-jump!
waggles around at approximately 7 Kc/s (depending on the stiffness of
the suspension and the mass of the diamond tip) until it once more
contacts the surface. This is not specified by the manufacturers, as
all their measurements were taken with the stylus in contact with the
record and no high-slew-rate vertical signals.
An oscilloscope trace shows the stylus performing part-cycles and some
really big disturbances give rise to several complete cycles. As this
is an inherent property of the cantilever stylus geometry, I don't doubt
that it would also be found in all the other makes of cartridge if
anyone took the trouble to look.
On 2025/8/12 8:43:11, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[]
pictures - of early experiments with constant linear, as opposed to
angular, velocity. Never caught on, presumably due to the mechanical
copmplexity.
There were several variants of the idea. The gramophone's normal
friction governor was made ineffective by turning it up to full speed,
then the surface speed of the disc was controlled by a small
three-weight centrifugal governor mounted on the sound box and running
on a rubber tyre in contact with the disc surface at the radius of reproduction.
With presumably something at the recording (cutting) end.
... Were many such discs made? (Or any other than test ones to
prove the principle?)>
...I saw the only known example
in the back store of the Science Museum a few years ago.
Those stores must be full of many weird and wonderful things!
The 1812 is always difficult to do properly: it _does_ sound best with a
good loud bang,
The other difficulty is overload: obviously you have to turn off any
sort of AGC or you don't hear the orchestra at all after the bangs,
... (Of course, the above YouTube clip will have gone
through several stages before it reaches YouTube playback - I don't know
if any of them made that aspect worse.)
... I remember particularly the recording just made in a
department store, including in-store announcement over the PA, which was
very you-were-there.
A good test for parallel-tracking mechanisms (or suspect pickup arms) is
to put on a 45 rpm 'single' with a knocked-out centre, as eccentric as
it will go - then play it at 78 rpm. If it doesn't track properly, a re-design is called for. (Turn down the volume for this test.)
There should be a society for the prevention of cruelty to machinery!
(Actually, wouldn't that tend to trigger the auto-lift, that detects the
end of the record by increased tracking rate? Though maybe some decks
don't have that, or it can be disabled.)>
Some of the most popular cartridges for general transcription work are
the Shure series, they are robust and free of any apparent vices, there
And IIRR the range included some that were fairly good but affordable.
It appears that this is due to the sharp-edged particles in the mixture giving a vertically-downwards 'cliff edge' that leaves the stylus
hanging in space. With nothing to support the free end, the stylus bar
Sort of like a ski-jump!
waggles around at approximately 7 Kc/s (depending on the stiffness of
the suspension and the mass of the diamond tip) until it once more
contacts the surface. This is not specified by the manufacturers, as
all their measurements were taken with the stylus in contact with the record and no high-slew-rate vertical signals.
Now there's a track to put on test discs I bet nobody's thought of: some deliberate ski-jumps!
There used to be a guy, Jeff Liebermann, in alt.internet.wireless who
could also go in great depth on his subject.
J. P. Gilliver <G6JPG@255soft.uk> wrote:
On 2025/8/12 8:43:11, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[]
pictures - of early experiments with constant linear, as opposed to
angular, velocity. Never caught on, presumably due to the mechanical
... Were many such discs made? (Or any other than test ones to
prove the principle?)>
There was a small catalogue of material issued on them and they still
appear in piles of old records from time to time. The attachments to
play them occasionally turn up at specialist auctions.
The problem with any long-playing record before the advent of tape was
the length of time the musicians had to play without making mistakes. A proportion of records were Take II or Take III (marked as a code in the
label surround) and they were only 3 minutes long . Because recording
blanks were very expensive to make, any performer who needed a fourth
take was usually booted out.
[...]
...I saw the only known example
in the back store of the Science Museum a few years ago.
Those stores must be full of many weird and wonderful things!
Including a Path|- poisson, Haddy's FFRR cutterhead (minus the magnet)
and a huge three-track tape recorder deck which Decca used, probably for
film soundtrack work. I think the cutterhead has since been put on
display 'front-of-house'.
[...]
The 1812 is always difficult to do properly: it _does_ sound best with a
good loud bang,
I re-issued a 1920's Woolworths record of it, played by George Cathie's orchestra (which was about 6 musicians from the North Pier Blackpool orchestra). The speed and the sheer enthusiasm of the tubular bells
player more than made up for the lack of bangs.
The other difficulty is overload: obviously you have to turn off any
sort of AGC or you don't hear the orchestra at all after the bangs,
Ahhhrgh! Shock horror!!! You don't use AGC for 'proper' professional recordings.
One of my tricks has been to feed the signals to two Tascam recorders,
one set 20dB lower than the other. I used the high level recording to
get the best signal-to-noise ratio but can insert the low-level one
(suitably balanced) if the high-level one has an overload. I see there
are now recorders on the market that do this automatically.
... I remember particularly the recording just made in a
department store, including in-store announcement over the PA, which was
very you-were-there.
That's when you suddenly realise how good just plain honest recording
can be.
A good test for parallel-tracking mechanisms (or suspect pickup arms) is >>> to put on a 45 rpm 'single' with a knocked-out centre, as eccentric as
it will go - then play it at 78 rpm. If it doesn't track properly, a
re-design is called for. (Turn down the volume for this test.)
There should be a society for the prevention of cruelty to machinery!
It shouldn't actually *break* anything if you are alert enough to stop
it when things start to go wrong.
(Actually, wouldn't that tend to trigger the auto-lift, that detects the
end of the record by increased tracking rate? Though maybe some decks
don't have that, or it can be disabled.)>
Ahhhrgh! Shock horror again !!!
Proper transcription decks don't have auto-stop or anything else
automatic, the operator is paid to do that. Some have pickup lifters
but many operators just rely on a steady hand. Parallel-trackers also
don't need anti-skating bias or other dangly bits of string, as there shouldn't be any sideways forces. By intercepting the tracking motor
servo, an electronic bias can be added to nudge the pickup past locked grooves or other obstructions, but this would normally left set to zero.
[...]
Some of the most popular cartridges for general transcription work are
the Shure series, they are robust and free of any apparent vices, there
And IIRR the range included some that were fairly good but affordable.
Unfortunately they have recently started to become 'cult' and the prices
have shot up.
Now there's a track to put on test discs I bet nobody's thought of: some
deliberate ski-jumps!
I had wondered about asking someone with a stereo cutterhead to make me
a test record but there are so many crackly 78s around that I don't have
any shortage of test material.
Hmm, hadn't thought you'd need a stereo head, which I can see of course
you would.>
Do - or did ever - any cutting equipment ever have a horizontal and a vertical drive, rather than the two 45 degree ones (with appropriate matrixing of signals, obviously)? Yes, I know very early ones did use
that anyway, before someone (Mr. Blumlein was it?) thought of the 45
degree trick, but I wondered if it was ever done afterwards. I can see
some advantages - the two directions of cut having different physics,
after all - as well as disadvantages (mainly, the matrixing needed).
On 2025/8/12 8:43:11, Liz Tuddenham wrote:
There was a famous LP of 1812 Overture where the cannon shots were
visible with the naked eye. The varigroove system spaced the grooves
well away on each side to allow the full amplitude. It was notorious
for throwing the stylus across the record if the playback system wasn't
well designed.
The 1812 is always difficult to do properly: it _does_ sound best with a
good loud bang, but getting the timing right is difficult: certainly,
the use of real artillery pieces almost never works properly in this
respect. The best compromise I've seen is an Albert Hall (so maybe
proms? Yes, 2004, Hall|-/Mark Elder and London Brass) one that used pyrotechnics. https://www.youtube.com/watch?v=qW4C2h3lPac&t=300 (I've directed you to the second set of bangs, which time pretty well though
not absolutely perfectly, just better than most; the first set just
after 3 minutes in aren't as well timed). [For some reason - probably YouTube's limits when it was uploaded - it's in two parts; part 1 is <https://www.youtube.com/watch?v=rgOGl_OWOqg> The bangs are all in the
second part, about 3 and 5 minutes in.]
On 12/08/2025 11:42, J. P. Gilliver wrote:
On 2025/8/12 8:43:11, Liz Tuddenham wrote:
There was a famous LP of 1812 Overture where the cannon shots were
visible with the naked eye. The varigroove system spaced the grooves
well away on each side to allow the full amplitude. It was notorious
for throwing the stylus across the record if the playback system wasn't
well designed.
The 1812 is always difficult to do properly: it _does_ sound best with a
good loud bang, but getting the timing right is difficult: certainly,
the use of real artillery pieces almost never works properly in this
respect. The best compromise I've seen is an Albert Hall (so maybe
proms? Yes, 2004, Hall|-/Mark Elder and London Brass) one that used
pyrotechnics. https://www.youtube.com/watch?v=qW4C2h3lPac&t=300 (I've
directed you to the second set of bangs, which time pretty well though
not absolutely perfectly, just better than most; the first set just
after 3 minutes in aren't as well timed). [For some reason - probably
YouTube's limits when it was uploaded - it's in two parts; part 1 is
<https://www.youtube.com/watch?v=rgOGl_OWOqg> The bangs are all in the
second part, about 3 and 5 minutes in.]
Apparently Tchaikovsky disliked the piece due to the difficulty of synchronising the bangs.
I rather like the version in the Gala Tribute to Tchaikovsky performed
in the ROH in 1993 (broadcast on TV and released on Laserdisc): it has
actual cannon on stage with smoke coming out of the barrels and
realistic bangs - I don't know how the effect was done.
On 2025/8/10 19:15:15, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
When the RIAA curve became standard after1954, everyone agreed on oneYes, I've seen it used - sort of in jest - on some modern releases. (I
characteristic and Decca fell in with the rest, so although their
records covered the full frequency range, they were no longer to the
FFRR standard. By then, every company had its own way of achieving the
RIAA standard or just bought kit from specialised manufacturers. The
difference between RIAA and FFRR was not as noticeable to the public as
the wider frequency range which they both gave. FFRR was (and still is)
a registered trademark, even though it has lost its original meaning.
think I may even have seen it on CDs!)
pictures - of early experiments with constant linear, as opposed to
angular, velocity. Never caught on, presumably due to the mechanical
[]
... Were many such discs made? (Or any other than test ones to
prove the principle?)>
There was a small catalogue of material issued on them and they still appear in piles of old records from time to time. The attachments to
play them occasionally turn up at specialist auctions.
Unless they were made with variable spacing, presumably you could devise
the mathematics to restore them if played on a normal CAV deck.
...ideally with some sort of auto-changeover (I
think the BBC just used two decks;
you occasionally hear them play some
"historically significant" recording, with a dip in surface noise every
few minutes! [I wonder if anyone's ever suggested they should insert it
in the gaps!]).
Once electronic recording was around, but before tape, did anyone in
effect do what later was done with tape, i. e. redo bits, recording onto
a disc that was processed to be playable - not necessarily more than a
few times - to reassemble the piece? Or was disc-to-disc sufficiently
lossy in quality that this wasn't on? (Or, maybe, processing a disc in
such a way wasn't practical, either for economic or technical reasons.)>
sometimes -
especially in things like radio station output - there is something that
cuts in in case of extreme overload, even if there isn't (as indeed,
there shouldn't be) any normal AGC-type control present.>
That's when you suddenly realise how good just plain honest recording
can be.
Binaural (as this was) can be impressive too, but of course has to be listened to on headphones.
A good test for parallel-tracking mechanisms (or suspect pickup arms) is >>> to put on a 45 rpm 'single' with a knocked-out centre, as eccentric as >>> it will go - then play it at 78 rpm. If it doesn't track properly, a
re-design is called for. (Turn down the volume for this test.)
There should be a society for the prevention of cruelty to machinery!
It shouldn't actually *break* anything if you are alert enough to stop
it when things start to go wrong.
Though I imagine the chance of damage to the stylus is non-zero.
(Actually, wouldn't that tend to trigger the auto-lift, that detects the >> end of the record by increased tracking rate? Though maybe some decks
don't have that, or it can be disabled.)>
Ahhhrgh! Shock horror again !!!
Proper transcription decks don't have auto-stop or anything else
automatic, the operator is paid to do that. Some have pickup lifters
but many operators just rely on a steady hand. Parallel-trackers also don't need anti-skating bias or other dangly bits of string, as there shouldn't be any sideways forces. By intercepting the tracking motor servo, an electronic bias can be added to nudge the pickup past locked grooves or other obstructions, but this would normally left set to zero.
Ah. The one I have (marantz TT520) sort of pretends to be a tape player
- it has fast-forward buttons and the like.
It has auto stop, though I'm not sure whether by detecting
increased tracking or just by position.
It always amused me that a lot of turntables of that era - both linear tracking and not - have those rings of dots around the rim, and a
control to adjust the speed until the dots appeared stationary - but I suspect in most cases, the flashing light used was derived from the
mains frequency (hence four rows of dots, for the two speeds at 50 and
60 Hz), rather than any quartz reference! (The mains isn't _that_
accurate a frequency reference; total number of cycles in a day is
carefully controlled, but instantaneous frequency slightly less so.)>
Do - or did ever - any cutting equipment ever have a horizontal and a vertical drive, rather than the two 45 degree ones (with appropriate matrixing of signals, obviously)? Yes, I know very early ones did use
that anyway, before someone (Mr. Blumlein was it?) thought of the 45
degree trick, but I wondered if it was ever done afterwards. I can see
some advantages - the two directions of cut having different physics,
after all - as well as disadvantages (mainly, the matrixing needed).
J. P. Gilliver <G6JPG@255soft.uk> wrote:
Possibly, but the material was not of any great interest. If you wanted
to make this a project, you would have two problems: actually getting
the material off the disc and correcting the speed, then finding anyone
who could be persuaded to listen to it. The second problem might be the
more difficult.
[...]
...ideally with some sort of auto-changeover (I
think the BBC just used two decks;
There were three systems:
a) Straight recordings
1 Disc 1 Side 1
2 Disc 1 Side 2
3 Disc 2 Side 1
4 Disc 2 Side 2
b) Auto couplings (for automatic record changers)
1 Disc 1 Side 1
2 Disc 2 Side 1
7 Disc 2 Side 2
8 Disc 1 Side 2
c) Broadcast couplings (for twin turntables)
1 Disc 1 Side 1
2 Disc 2 Side 1
3 Disc 1 Side 2
4 Disc 2 Side 2
5 Disc 3 Side 1
(There was another 'system' used for the Nuremburg trials - completely
random and chaotic.)
you occasionally hear them play some
"historically significant" recording, with a dip in surface noise every
few minutes! [I wonder if anyone's ever suggested they should insert it
in the gaps!]).
I always do. The difficult bit is the quality of the surface noise,
which changes with the surface speed, so it is different between the end
of one the disc and at the start of the next. There are various kludges
for disguising the changeovers, but they aren't very nice.
The most effective way was to use broadcast couplings but have one
recorder running outside-to-inside and the other running inside to
outside. Each changeover was then between two outsides or two insides.
The snag was making sure the playback operator didn't get confused,
otherwise the needle dropped off the edge at the 'start' of the second
disc and played the turntable (...or played the label of the third
disc).
Most of the techniques we think of as 'modern' were practiced as far
back as the turn of the last century. One company in the acoustic
recording days used a gas tap to cross-fade between two horns, one for
the singer and one for the accompaniment. Dubbing from disc to disc or playing-in an earlier contribution to a later performance was not
uncommon. There were many compilation records issued once electrical recording came in.
With modern playback equipment these subterfuges can sometimes be
spotted but they would have passed completely unnoticed on clockwork gramophones. The studio equipment was always a long way ahead of the 'budget' playback equipment which the public bought.
but many operators just rely on a steady hand. Parallel-trackers also
don't need anti-skating bias or other dangly bits of string, as there
shouldn't be any sideways forces. By intercepting the tracking motor
servo, an electronic bias can be added to nudge the pickup past locked
grooves or other obstructions, but this would normally left set to zero.
Ah. The one I have (marantz TT520) sort of pretends to be a tape player
- it has fast-forward buttons and the like.
I have used a Sony direct-drive turntable for professional work but the
< http://www.poppyrecords.co.uk/other/Turntables/parallel-tracker.htm>
Some of the mechanical gramophones had the auto-stop operated by the
return stroke of the arm when it met an eccentric locked groove.
Others had a rate-proportional mechanism that moved a fibre block intoIngenious, as always! I never played with posher or older machines where
the path of a rotating projection on the spindle under the turntables.
The block was on a swinging arm, connected by a friction clutch coupling
to a lever on the tone-arm pivot. It had a chamfered corner, so if
the arm only swung it forward a small distance per rev, it was pushed
back to place each time the projection hit the chamfer. (The slipping friction coupling allowing this to happen) If it moved much further in
one rev, the projection hit it squarely on one face and displaced it
against another lever which tripped the brake mechanism.
tracking and not - have those rings of dots around the rim, and a
control to adjust the speed until the dots appeared stationary - but I
The difference in pitch would hardly be noticeable. Where speed was
The stroboscopes for 78 aren't accurate anyway. Whilst the formulae for
45 and 33+1/3 rpm come out to a whole number of dots, the formula for 78
rpm doesn't. In any case, most pre-merger Columbias and Regals were 80
rpm and a lot of the older companies were not too particular about the
speed. Acoustic Edison Bells could have been recorded at any speed
between 72 and 82 rpm.
[...]
Do - or did ever - any cutting equipment ever have a horizontal and a
vertical drive, rather than the two 45 degree ones (with appropriate
Some cutterheads, especially in the early days of stereo, used lateral/vertical drive, rather than 45-degree. This allowed the
designers to concentrate on getting the best frequency response out of
the horizontal channel, where errors were most obvious. Some of the
later 45/45 cutterheads achieved an amazingly good performance by brute force, with drive amplifiers in the killowatt range ( 4 x 4CX250Bs in
push-pull class B) and ceramic-insulated coils cooled by helium.
On 2025/8/13 9:58:44, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[constant-linear-velocity]
Possibly, but the material was not of any great interest. If you wanted
to make this a project, you would have two problems: actually getting
the material off the disc and correcting the speed, then finding anyone
who could be persuaded to listen to it. The second problem might be the more difficult.
What sort of material?>
Presumably broadcasters - and other professionals - didn't use
autochangers;
I presume they bought two copies (to do the middle
changeover), or these days just recorded the first or second half (or, indeed, the lot, which would make the whole thing easier and remove the stress on the operator).
(There was another 'system' used for the Nuremburg trials - completely random and chaotic.)
Presumably because done by those not trained in such matters, who just grabbed the first available blank each time?>
you occasionally hear them play some
"historically significant" recording, with a dip in surface noise every
few minutes! [I wonder if anyone's ever suggested they should insert it
in the gaps!]).
I always do. The difficult bit is the quality of the surface noise,
which changes with the surface speed, so it is different between the end
of one the disc and at the start of the next. There are various kludges for disguising the changeovers, but they aren't very nice.
Assuming we're talking about transfers, rather than public
"performances" (do you do those?!?),
are the gaps meant to be there
anyway, or just there as a practical necessity? I would imagine -
especially for classical music written before the recording era, which
is most of it - there wouldn't _be_ few-seconds gaps in the score,
certainly not at convenient intervals. So no need to actually insert
noise. Or are you just talking of masking the _change_ of noise characteristic at the changes.>
Your use of the word gas reminds me of something I wish I'd encountered:
the auxetophone, or pneumatic player. This (I'm sure you know, but for
our wider audience) used compressed air to play back discs - the pickup
head varying the amount of air by operating (being) a valve: a form of amplification needing no electronics.
I believe it was loud enough to
fill a field outdoors.
I've heard one disadvantage was a constant
audible hiss, but I imagine that wasn't a great problem from greater distances where most of the audience were; I would have thought the
major problem (other than keeping the whole system working, including
the supply of compressed air at an even pressure in the middle of a
field!) would be that the mechanism probably was rather harsh on records.
I remember one disc I had (still have) was so badly scratched that I eventually gave up trying to get it to play through the locked grooves,
and just settled for repeated attempts until I'd got each revolution,
but not (pace Eric!) in the right order, then did a lot of cut and paste
in Goldwave to re-sort it. Presumably you do plenty of that (including
I'm sure in your case playing some of the grooves backwards).>>>
< http://www.poppyrecords.co.uk/other/Turntables/parallel-tracker.htm>
I was going to say looks very industrial! Then I realised you'd
repackaged it, presumably to make a robust unit for carrying.
[]
Some of the mechanical gramophones had the auto-stop operated by the
return stroke of the arm when it met an eccentric locked groove.
Hence the eccentric locked groove - though that seems rarer than you'd expect, given that trigger effect - I think I've seen more 78s that
_didn't_ have one than did. Was it somebody's patent?
I never played with posher or older machines where
just braking was involved; only the ones that did complete
arm-lift-and-park (or start next record), which were also presumably ingenious mechanisms.
The stroboscopes for 78 aren't accurate anyway. Whilst the formulae for
45 and 33+1/3 rpm come out to a whole number of dots, the formula for 78 rpm doesn't. In any case, most pre-merger Columbias and Regals were 80
I don't think I've ever seen a turntable with dots for 78 anyway - just
four rows for 33/45 at 50/60 Hz. Did they exist? (If so, I think I'd
rather have had one that jumped every 10/13 second than one I knew was wrong.)
rpm and a lot of the older companies were not too particular about the speed. Acoustic Edison Bells could have been recorded at any speed
between 72 and 82 rpm.
Sometimes stated on the label, sometimes not. Many clockwork players had
a lever to vary the speed, from what I've seen.>
... Some of the
later 45/45 cutterheads achieved an amazingly good performance by brute force, with drive amplifiers in the killowatt range ( 4 x 4CX250Bs in
I remember that valve number from my radio amateur days (not that I was
ever into high power, but the number stuck in the mind).
push-pull class B) and ceramic-insulated coils cooled by helium.
(Wow.) I was just wondering - well _after_ the 45/45 system was the norm
- if any companies still did use horizontal and vertical drive, fed from
a matrix, rather than direct 45/45 drive.
J. P. Gilliver <G6JPG@255soft.uk> wrote:
Presumably broadcasters - and other professionals - didn't use
autochangers;
Absolutely not. They cost more than the standard turntable (though less
than a professional one) and they were generally of poorer quality aimed
at the domestic market. One huge disadvantage was their inability to
play 16" transcription discs, so they would be limited to commercial
I presume they bought two copies (to do the middle
changeover), or these days just recorded the first or second half (or,
indeed, the lot, which would make the whole thing easier and remove the
stress on the operator).
Until the 1960s, discs were played into the programme in real time. The operators were so skilled that an audible changeover or mis-timing was a
rare occurrence.
[...]
(There was another 'system' used for the Nuremburg trials - completely
random and chaotic.)
On one disc the drive pin hole had been used for the centre pin, so the recording was about 2cm off-centre. The lack of training - or whatever caused errors like that - was quite mind-boggling.
Whenever possible they tried to break the music at a change of mood or
the end of a passage where there was a pause. The orchestra stopped at
a given point marked in the score and there was a tendency to try to
'tidy up' the last few notes, which made it difficult to edit onto the
next bit. I can never listen to 'Danse Macabre' without mentally
reaching out to turn the disc over at a certain point.
Broadcast transcriptions were a different matter, they played right
through but the operator could record two discs simultaneously for a few seconds. The BBC 'D' recorder would put a scroll on the two discs when
they were running simultaneously, so that the playback operator could
see exactly where they coincided. and could match them so that there was
the auxetophone, or pneumatic player. This (I'm sure you know, but for
I believe it was loud enough to
fill a field outdoors.
More than that, it was reputed to be audible at a distance of 10 miles.
I've heard one disadvantage was a constant
audible hiss, but I imagine that wasn't a great problem from greater
distances where most of the audience were; I would have thought the
major problem (other than keeping the whole system working, including
the supply of compressed air at an even pressure in the middle of a
field!) would be that the mechanism probably was rather harsh on records.
The machine was transported in a motor car, one back wheel of which was
then jacked up and the wheel taken off .. A belt was slipped around the brake drum and drove the compressor, which was placed on the ground
behind the car.
That's one of the methods I use for really bad jump-grooves. Sometimes tilting the whole player can force the stylus to follow the correct
path.
I wanted to fit a small flat-screen X-Y oscilloscope into the controlSounds like a fun idea, though!
area to display the stylus movement, but haven't had much success. That
saga is still playing out on <sci.electronics.design>
I never played with posher or older machines where
just braking was involved; only the ones that did complete
arm-lift-and-park (or start next record), which were also presumably
ingenious mechanisms.
They were very clever. The bottom of the range was the BSR which was
made of stamped-out bits of plate and a die-cast cam wheel; the top end
was Garrard, with beautifully-finished precision components and a finely-machined cam. When new, the BSR mechanism rattled a bit - but
it made a serviceable job of playing records; the Garrard was somewhet
better and the mechanism worked beautifully. After a few years the
Garrard wore slightly and all sorts of things began to go wrong, the BSR
just carried on rattling and clanking for decades more, because all the precision had been designed-out at the drawing board stage.
The Garrard 301 had a 78 stroboscope marking on the turntable rim and a magnetic eddy-current braking disc on the motor to give small speed variations.
later 45/45 cutterheads achieved an amazingly good performance by brute
force, with drive amplifiers in the killowatt range ( 4 x 4CX250Bs in
I remember that valve number from my radio amateur days (not that I was
ever into high power, but the number stuck in the mind).
They were force-air-cooled transmitting tetrodes that needed a couple of kilovolts on the anodes.
On 2025/8/13 13:41:54, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[]
Presumably broadcasters - and other professionals - didn't use
autochangers;
Absolutely not. They cost more than the standard turntable (though less than a professional one) and they were generally of poorer quality aimed
at the domestic market. One huge disadvantage was their inability to
play 16" transcription discs, so they would be limited to commercial
When I saw that figure, at first I thought you were referring to the
speed, then I realised the " meant size.
I never actually encountered a 16 2/3 RPM disc, though I presume they
must have been common at one time as from what I remember (I was born
1960, so would have started to be aware in th early '60s - and the
equipment around then, in homes ayway, probably included lots from the
'50s), virtually any record player came with all four speeds.
The only common use I _heard of_ for them was talking books for the
blind, but I never actually encountered one.
(I think even half that - 8 1/3? - was used.)I believe it was but the players were specialised machines that would
I presume they bought two copies (to do the middle
changeover), or these days just recorded the first or second half (or,
indeed, the lot, which would make the whole thing easier and remove the
stress on the operator).
Until the 1960s, discs were played into the programme in real time. The operators were so skilled that an audible changeover or mis-timing was a rare occurrence.
But, presumably, if the only recording available was one where two
individual segments were on the opposite sides of the same disc, they'd _have_ to buy two copies, or have a noticeable pause.>
[...]
On one disc the drive pin hole had been used for the centre pin, so the recording was about 2cm off-centre. The lack of training - or whatever caused errors like that - was quite mind-boggling.
I suppose for recorded speech just about tolerable.
(And, presumably,
recoverable by doing an equal error to play it back.)
What speed were
they recorded at?
Were they actually reproduced, so a mother/master/etc.
system? I can't see them being exactly a million-seller, though
presumably all the governments etc. involved wanted access. Or were the blanks treated in some way to make them playable and durable?
[]
Ah, the associations we make with a particular recording! Usually the
first one we hear,
Broadcast transcriptions were a different matter, they played right
through but the operator could record two discs simultaneously for a few seconds. The BBC 'D' recorder would put a scroll on the two discs when they were running simultaneously, so that the playback operator could
see exactly where they coincided. and could match them
Bit like film projectionists.
[...]the auxetophone,
The machine was transported in a motor car, one back wheel of which was then jacked up and the wheel taken off .. A belt was slipped around the brake drum and drove the compressor, which was placed on the ground
behind the car.
Fascinating as usual! what _did_ kill off the machines - or, were only
one or two ever made?
I wanted to fit a small flat-screen X-Y oscilloscope into the controlSounds like a fun idea, though!
area to display the stylus movement, but haven't had much success. That saga is still playing out on <sci.electronics.design>
Yes; the whole thing gave the impression, as someone once commented, of having been built in a shipyard.
There's a lot to be said for clunky!
[]
The Garrard 301 had a 78 stroboscope marking on the turntable rim and a magnetic eddy-current braking disc on the motor to give small speed variations.
Ah, the first time I encountered that sort of braking was on a Philips reel-to-reel video recorder; the head drum was as far as I could
understand designed to run faster than needed, with an
eddy-current-braking disc used to bring it into sync..
I had a set
with - I think - a 6146 in it, but never used it).
Yes, a lot of broadcasts were recorded on 16" discs - as were film soundtracks.
Seems odd that it was there on virtually any gramophone in the '50s andI never actually encountered a 16 2/3 RPM disc, though I presume they
must have been common at one time as from what I remember (I was born
1960, so would have started to be aware in th early '60s - and the
equipment around then, in homes ayway, probably included lots from the
'50s), virtually any record player came with all four speeds.
I have never seen one either - nor met anyone, among the 100 or so
collectors that I know, who has..
The only common use I _heard of_ for them was talking books for the
blind, but I never actually encountered one.
I suspect they were rented out from a circulating library and destroyed
when they were life-expired.
(I think even half that - 8 1/3? - was used.)I believe it was but the players were specialised machines that would
not play normal discs.
Ah, the associations we make with a particular recording! Usually the
first one we hear,
There was a folk dance band which had a particularly haunting sound when
the top octave of the synthesizer was played. One day they played for a
BBC radio programme - but it didn't sound like them. I asked what had happened and they said they had sent the synthesizer for a check-up in advance of the recording; the technician had found a fault in the top
octave and put it right.
Compressed air amplifiers were also attached to musical instruments so
that fewer were needed in an orchestra but fears of unemployment among musicians soon put a stop to that.
Yes; the whole thing gave the impression, as someone once commented, of
having been built in a shipyard.
That sounds more like Ferrograph.
The Garrard 301 had a 78 stroboscope marking on the turntable rim and a >>> magnetic eddy-current braking disc on the motor to give small speed
variations.
Ah, the first time I encountered that sort of braking was on a Philips
reel-to-reel video recorder; the head drum was as far as I could
understand designed to run faster than needed, with an
eddy-current-braking disc used to bring it into sync..
I hadn't seen that particular model but eddy-current braking is a very
smooth and controllable system. I employed it on the Recordgraph player
to back-tension the film - using a single-phase fractional horsepower industrial fan motor with a skewed rotor, fed from DC.
< http://www.poppyrecords.co.uk/other/recordgraph/recordgraph.htm>
[...]
I had a set
with - I think - a 6146 in it, but never used it).
I'm currently constructing an all-valve transceiver for 2 metres but the output is only about 10 Watts from a QQVO3-10.
On 2025/8/13 20:24:47, Liz Tuddenham wrote:
[]
Yes, a lot of broadcasts were recorded on 16" discs - as were film soundtracks.
I seem to remember reading somewhere that the origin of the 33 1/3 speed
was film soundtracks.>
I have never seen one either - nor met anyone, among the 100 or so collectors that I know, who has..Seems odd that it was there on virtually any gramophone in the '50s and
'60s.
There was - still is - a tendency
to make equipment for the blind very chunky and clunky; for most blind
folk it doesn't need to be, and it is rather irritating to them. But I
guess if it has to for a few, it is for all, as the market is already
tiny. (Well, not tiny, but below the economies-of-scale threshold.)
Yes; the whole thing gave the impression, as someone once commented, of
having been built in a shipyard.
That sounds more like Ferrograph.
I still have my department's Ferrograph, I saved when it was in danger
of being thrown out. Not sure I would be able to lift it now ...
< http://www.poppyrecords.co.uk/other/recordgraph/recordgraph.htm>
Hmm, lateral recording with a groove spacing of only .01" - must have
needed to be quite quiet recordings!
The multiple-grooved plastic belt principle reminds me of another
system, mainly (if not entirely) in Germany, that used the same
principle (but unsprocketed film, and I think considerably coarser).
I
saw one once in a museum in Germany - can't remember if it was working
or not. Since it wasn't a recording system but only playback (the belt cartridges were [somewhat] mass-produced with recordings on them), I
couldn't really see the point - it used basically gramophone pickups -
over a record player, and presumably nor could enough other people, as
it disappeared.>
I haven't keyed a transmitter on the amateur bands for what
must now be some decades. (Has that branch of government caught up sufficiently that your change of name caused no problems? I hope so.)
J. P. Gilliver <G6JPG@255soft.uk> wrote:
On 2025/8/13 20:24:47, Liz Tuddenham wrote:
[]
Yes, a lot of broadcasts were recorded on 16" discs - as were film
soundtracks.
I seem to remember reading somewhere that the origin of the 33 1/3 speed
was film soundtracks.>
I'm not sure if it was the origin, but the 16" film soundtrack discs ran
at 33 +1/3 rpm, started at the centre and were vertically modulated. Obviously the overall format was designed to play for the time of one
reel of film; as they were synchronised to the projector with a bowden
cable, that exact speed may have been chosen to give a sensible gear
ratio
[...]
I have never seen one either - nor met anyone, among the 100 or soSeems odd that it was there on virtually any gramophone in the '50s and
collectors that I know, who has..
'60s.
One of life's great mysteries.
I have seen some terrible designs which were supposed to help disabled people: A player for the blind that was menu-driven, so one false
key-press could drop the user into a jungle of sub-menus from which
there was no recovery. A telephone with the minor controls labelled in
shiny black lettering on a dull black background and a ringer that was
ear-splitting to a hearing person but so high pitched that
hearing-impaired people couldn't hear it.
Hmm, lateral recording with a groove spacing of only .01" - must have
needed to be quite quiet recordings!
The original Recordgraph was a very well-made machine, not unlike a Bell
& Howell projector in appearance and engineering quality. A sapphire
quality was quite acceptable for news gathering, as recordings of the
D-Day landings showed (the machine that made those recordings was accidentally dropped in the sea but still functioned after drying out).
The multiple-grooved plastic belt principle reminds me of another
system, mainly (if not entirely) in Germany, that used the same
principle (but unsprocketed film, and I think considerably coarser).
Tefifon
They sometimes turn up at vintage radio fairs. I think the idea was for non-stop background music and the main income would have been from the
sale of belts of popular music.
[...]
I haven't keyed a transmitter on the amateur bands for what
must now be some decades. (Has that branch of government caught up
sufficiently that your change of name caused no problems? I hope so.)
When I applied for my licence earlier this year, I was surprised at the 'can-do' attitude of that branch of Ofcom; quite unlike the Gestapo
approach of the old Post Office Wireless Department. They accepted ny
deed poll and an entry in the RSGB Call Book from the late 1970s, which confirmed the details I had given them - so they promptly issued a full licence and reinstated my old call sign.
On 2025/8/14 8:9:24, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
On 2025/8/13 20:24:47, Liz Tuddenham wrote:
[]
Yes, a lot of broadcasts were recorded on 16" discs - as were film
soundtracks.
I seem to remember reading somewhere that the origin of the 33 1/3 speed >> was film soundtracks.>
I'm not sure if it was the origin, but the 16" film soundtrack discs ran
at 33 +1/3 rpm, started at the centre and were vertically modulated. Obviously the overall format was designed to play for the time of one
reel of film; as they were synchronised to the projector with a bowden cable, that exact speed may have been chosen to give a sensible gear
ratio
Presumably if a section of film was damaged, it had to be replaced with
a gash length of blank film to keep things in sync.!>
[...]
(I remember being most impressed when I first realised they'd
_combined_ the motor with the mains transformer, i. e. there was only
one laminated-core object in the whole player.)
Aargh, I strongly dislike menus even as a sighted person - I think their
main reason for existence, in simple appliances, is to save the cost of
one switch here and there.
The female of my
friends had been a medical secretary, and could certainly out-type me - though liked a robust keyboard, as she'd learnt on manual typewriters
and hit the keys hard.)
The original Recordgraph was a very well-made machine, not unlike a Bell
& Howell projector in appearance and engineering quality.
(As one of the school projectionists, I had access to the two machines -
the old one which was definitely B&H, and the newer which I think was so badged, but made in - I think Hong Kong. It had clever self-threading -
you just poked the end of the film into it - which I must admit worked
very well; but, I far preferred using the old manual machine. Felt a lot
less "plasticky", and threading it up I found no problem. [On the whole
I preferred reel-to-reel tape machines to cassettes, too, and not just
for quality reasons.])
When I applied for my licence earlier this year, I was surprised at the 'can-do' attitude of that branch of Ofcom; quite unlike the Gestapo approach of the old Post Office Wireless Department.
Ah, I never had to deal with them. (Were they still in place around
1980? That's when I got my licence - I waited a bit extra to get my
initials, which were not far in the future [they would let you ask for a specific call, but you had to wait until it would come up anyway], and I remember them being quite helpful over the matter, but I can't remember whether it was GPO or OfCom I dealt with.)
J. P. Gilliver <G6JPG@255soft.uk> wrote:
Presumably if a section of film was damaged, it had to be replaced with
a gash length of blank film to keep things in sync.!>
Yes - and duplicate sets of discs were sometimes sent out in case one
got broken.
[...]
(I remember being most impressed when I first realised they'd
_combined_ the motor with the mains transformer, i. e. there was only
one laminated-core object in the whole player.)
That became possible when transistor amplifiers started to be used.
Some years before that there was a single-valve record player which
tapped the heater supply for a UL84 off the motor and rectified the HT straight off the mains with a selenium rectifier pack. This meant that
the leads to the cartridge could be at mains potential - and they
weren't double-insulated.
Aargh, I strongly dislike menus even as a sighted person - I think their
main reason for existence, in simple appliances, is to save the cost of
one switch here and there.
They can be a real impediment to quick and accurate operation. I thinkl
they should be illegal in any device accessible to a car driver.
and hit the keys hard.)
I learnt on an Imperial 66, which took a bit of thumping.
Out school never aspired to anything as modern as a Bell & Howell, I was projectionist with a BTH 301 which kept breaking down. I remember two
of us taking it in turns to stand on a chair and wind the takeup spool
with a pencil for several hours, after the takeup drive system broke
down at the start of a long show.
The GPO were very heavy-handed in the 1970s when I was first licenced:
once an officer waved a warrant at my mother and just walked into the
house. It appears that a neighbour had complained about TV interference
and I was the nearest 'ham'. After inspecting the transmitter, the
officer admitted that the neighbour's rental set was type that was
notorious for having spurious responses.
On 2025/8/14 22:20:37, Liz Tuddenham wrote:
Some years before that there was a single-valve record player which
tapped the heater supply for a UL84 off the motor and rectified the HT straight off the mains with a selenium rectifier pack. This meant that
the leads to the cartridge could be at mains potential - and they
weren't double-insulated.
Economy designs aren't new!> [...]
The GPO were very heavy-handed in the 1970s when I was first licenced:
once an officer waved a warrant at my mother and just walked into the house. It appears that a neighbour had complained about TV interference and I was the nearest 'ham'. After inspecting the transmitter, the
officer admitted that the neighbour's rental set was type that was notorious for having spurious responses.
These days you'd not have been so lucky, I fear: the neighbour's right
to use shoddy kit would have been seen as greater than your rights.
J. P. Gilliver <G6JPG@255soft.uk> wrote:
Economy designs aren't new!> [...]
That was taking it to extremes. The speed change was a length of
jewellers wire running between the selector lever and the idler carrier through a bit of bent brass tubing.
These days you'd not have been so lucky, I fear: the neighbour's right
to use shoddy kit would have been seen as greater than your rights.
The predominance of QRM suggsets that cheapness and expediency has long over-ruled the need for reliable communication. (I believe the laws on interference are more strictly enforced in Germany because they have a long-wave data system.)
The latest manifestation of this misguided approach is the conversion of
the telephone system to make it dependent on mains power at the
subscriber's premises. Any natural disaster that affects the mains
supply will take out communications when they are most needed. With a
few well-place acts of sabotage, Putin (or even a les well-heeled
agressor) could have the whole country at his mercy in a few days.
On 2025/8/15 19:19:13, Liz Tuddenham wrote:
J. P. Gilliver <G6JPG@255soft.uk> wrote:
[]
Economy designs aren't new!> [...]
That was taking it to extremes. The speed change was a length of
jewellers wire running between the selector lever and the idler carrier through a bit of bent brass tubing.
Rim drive, I presume?
These days you'd not have been so lucky, I fear: the neighbour's right
to use shoddy kit would have been seen as greater than your rights.
The predominance of QRM suggsets that cheapness and expediency has long over-ruled the need for reliable communication. (I believe the laws on interference are more strictly enforced in Germany because they have a long-wave data system.)
Oh; what do they use it for - something like our power system switching?>
The latest manifestation of this misguided approach is the conversion of the telephone system to make it dependent on mains power at the subscriber's premises. Any natural disaster that affects the mains
supply will take out communications when they are most needed. With a
few well-place acts of sabotage, Putin (or even a les well-heeled
agressor) could have the whole country at his mercy in a few days.
Oh, you mean the end of POTS. Yes, I can't really see the justification
- at least, I don't accept the reasons given ("can't get the parts" and
the like - rubbish; the system had been outdated/obsolete for
sufficiently long that they must have put in place parts sourcing many
years ago).
I'm not sure what they're doing about people who _need_ a 'phone for
medical or other reasons.
Until recently the secret underground bunkers still kept manaual
switchboards as a last-ditch insurance against more sophisticad methods failing in emergency. I hear through the grape vine that they have now
been scrapped.They are feeding them a load of pacifying bulshit and will let them die
if there is ever a real emergency. They don't care - the cheapest must prevail. We need a moderate peacetime disaster with a few dozen
avoidable deaths, before the Government wakes up from sleepwalking into
a much bigger disaster.
almost run in grid current. It was badged "Marconiphone" which was originally the prestige label of EMI.
over-ruled the need for reliable communication. (I believe the laws on
interference are more strictly enforced in Germany because they have a
long-wave data system.)
Oh; what do they use it for - something like our power system switching?>
I understand it was used for time-clock switching, like the R4 signals,
but instead of trying to shut it down, they extended it to cover other national services. I don;t have the details but I expect they are
online somewhere.
Oh, you mean the end of POTS. Yes, I can't really see the justification
Until recently the secret underground bunkers still kept manaual
switchboards as a last-ditch insurance against more sophisticad methods failing in emergency. I hear through the grape vine that they have now
been scrapped.
[...]
I'm not sure what they're doing about people who _need_ a 'phone for
medical or other reasons.
They are feeding them a load of pacifying bulshit and will let them die
if there is ever a real emergency. They don't care - the cheapest must
prevail. We need a moderate peacetime disaster with a few dozen
avoidable deaths, before the Government wakes up from sleepwalking into
a much bigger disaster.
Oh, you mean the end of POTS. Yes, I can't really see the justification
I have always thought the emergency "bunkers" - and allied
infrastructure - were pretty hopeless at best; not to denigrate the
attempts, but "Threads" and other such have shown how ineffective they'd
be in practice. OK, there will be_some_ aspects we don't know about,
but I can't really imagine there is much that will maintain civilisation
- I think if the balloon goes up, a quick death is perhaps the best
solution. Let's just hope we can keep the various balloons anchored!
(This morning's Alaska doesn't sound hopeful, but then I didn't expect
much from it.)>
On 16/08/2025 15:19, J. P. Gilliver wrote:
As the old mechanical exchanges came to the end of life, and electronics became cheaper, they switched to using ADC and DAC converters on eachOh, you mean the end of POTS. Yes, I can't really see the justification
wire pair at the exchange and digital transfer and switching internally
and between exchanges. The only analogue part of a phone call was
between the subscriber and the exchange. Then, they worked out that the analogue bit in the street was slowing down the broadband signals. They
then started moving the digital interfaces further out, using optical
fibre to the box in your street. Now they are rapidly rolling out fibre
to the premises. with optical switches in the boxes. This means they can
no longer send power to your phone. We got faster internet, and they got less maintenance to do. Win, win.
A lot of routers have the ADC and a power supply in the box, and some
can even fully emulate a POTS line so, if you wish, you can even keep
your old pulse dial phone with the bell.
They could still, technically, use a central power source for their--
bits, but powering the consumer stuff becomes our problem. I am unusual
in that if the power round here goes off, I have about 12 hours of
battery power available before I need to start the standby generator.
Last time we had a power cut, it took a couple of hours before the
laptop complained about its internal battery going flat. I use a 4G
router with a six hour internal battery life, and the lights are all 12
volt anyway.
On 16/08/2025 15:19, J. P. Gilliver wrote:
I have always thought the emergency "bunkers" - and allied
infrastructure - were pretty hopeless at best; not to denigrate the
attempts, but "Threads" and other such have shown how ineffective they'd
be in practice. OK, there will be_some_ aspects we don't know about,
but I can't really imagine there is much that will maintain civilisation
- I think if the balloon goes up, a quick death is perhaps the best
solution. Let's just hope we can keep the various balloons anchored!
(This morning's Alaska doesn't sound hopeful, but then I didn't expect
much from it.)>
Depends on what the intention is.
Even a ROC 'bunker' will give protection from the effects of fall-out.
The military have prefabricated ones that can be erected in the field
(you have to dig the hole) and will probably give a similar level of protection.
It could be said that a 'bulletproof' vest is useless because it will
not protect you from an artillery shell.