• Re: OT: Governing the speed of a cassette desk

    From tony sayer@tony@bancom.co.uk to uk.tech.broadcast on Tue Aug 5 12:39:21 2025
    From Newsgroup: uk.tech.broadcast

    In article <1rg97ie.14rbx2sssytvgN%liz@poppyrecords.invalid.invalid>,
    Liz Tuddenham <liz@poppyrecords.invalid.invalid> scribeth thus
    tony sayer <tony@bancom.co.uk> wrote:

    In article <1rg7b0d.1sqepa3lqdsliN%liz@poppyrecords.invalid.invalid>,
    Liz Tuddenham <liz@poppyrecords.invalid.invalid> scribeth thus
    NY <me@privacy.net> wrote:

    [...]
    I will check it very carefully for coating splitting/cracking and red
    powder.

    It's very rare that they decompse that far, but it is worth checking.

    At least I have a digital copy of it. It would have been nice to have
    played it with a proper 78 needle to avoid some of the surface noise
    that you get with an LP stylus. I played it at 33 1/3 rpm and then
    resampled it to 78 rpm because my record deck doesn't do 78.


    That's a terrible way of dealing with them (although not as bad as
    playing them with a steel needle, which will destroy the grooves
    completely). If you live anywhere near Bath, contact me by e-mail and I
    will copy them for you free of charge.


    I knew we should have kept my grandpa's radiogram - ugly bit of
    furniture in a cabinet about 6 feet long but its turntable had a
    flip-over stylus for 33/45 or for 78 rpm records.

    You would still have been unlikely to get the best out of it because the
    recording characteristics for microgroove records were usually different
    from those for coarse-grooved discs - although the BBC used different
    characteristics at different times and may have used RIAA towards the
    end of the disc era. They recorded contributors personal copies with a
    commercial characterisitc but had their own curves for transcription
    discs: the BBC 'D' curve, approximately 2dB per octave.


    Remember when i left school and started work at Pye TVT (TeleVision
    Transmitters) in Coldhams lane Cambridge, there was a sound products
    area and they made this transcription unit Thorens deck and a disc amp
    section with no end of EQ settings anyone else see one?..

    I've not seen that particular unit but there have been quite a few
    pieces of multi-equalisation equipment over the years.

    The basic parameters are the mid-frequency transition from constant
    velocity to constant amplitude, the bottom point at which the correction
    is discontinued and the point above which pre-emphasis applied to high >frequencies. These are usually expressed as time constants and so three >numbers can represent the entire characteristic for a given disc.

    In order to simplify this, for people who don't like numbers, the
    equipment manufacturers resorted to switching the time constants in >configurations corresponding to individual disc manufacturers. Thus, if
    it says "HMV" on the label, you put the switch to "HMV" and it selects
    an appropriate set of three time constants. Unfortunately the record >manufacturers used different time constants at different times, so a
    single setting can't always be right. Furthermore, some records
    recorded by one company may have been pressed with a different company's >label, so the label is an unreliable guide.

    The characteristics used by some companies in the early electrical
    recording days were either unknown to the companies themselves (if they >didn't have a way of testing them) or may have become lost in the mists
    of time. The whole system is a mess and sometimes a good practiced ear
    is the only way to approximate the settigs.



    Well the units I'm referring to were sold to broadcasters world-wide and
    did go to the BBC and the commercial outfits but they were quite
    comprehensive. It did use a Thorens deck and IIRC i think they were
    modified to either do instant start of could do 78 RPM but this was a
    long time ago now they were built on a floor stand trolley mounted
    arrangement with a panel that had a monitoring speaker for cueing etc..

    Theres a community radio station here in Cambridge they used to have an
    outfit called the "shellac collective" to be a member i think you had to possess an EMT turntable else you were a non entity!.

    One of they did have an Edison phonograph that was or could be miked up
    that did sound surprisingly good!...
    --
    Tony Sayer


    Man is least himself when he talks in his own person.

    Give him a keyboard, and he will reveal himself.


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  • From liz@liz@poppyrecords.invalid.invalid (Liz Tuddenham) to uk.tech.broadcast on Sat Aug 9 19:12:10 2025
    From Newsgroup: uk.tech.broadcast

    tony sayer <tony@bancom.co.uk> wrote:

    [...]
    Theres a community radio station here in Cambridge they used to have an outfit called the "shellac collective" to be a member i think you had to possess an EMT turntable else you were a non entity!.

    I have serviced an EMT for a transcription engineer but could never
    afford one myself. There are several turntables of quality which is
    comparable in most aspects except for rumble. A lot of broadcast EMTs
    were fitted with an SME arm - but the whole radial arm business is
    inherently flawed and the biggest improvement is to be had by replacing
    it with a parallel-tracking arm..


    One of they did have an Edison phonograph that was or could be miked up
    that did sound surprisingly good!...

    If you hear one in good condition playing unworn cylinders, it is quite
    amazing how good they are.
    --
    ~ Liz Tuddenham ~
    (Remove the ".invalid"s and add ".co.uk" to reply)
    www.poppyrecords.co.uk
    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From tony sayer@tony@bancom.co.uk to uk.tech.broadcast on Mon Aug 11 16:24:24 2025
    From Newsgroup: uk.tech.broadcast

    In article <1rgtboc.tx90l91kk9py0N%liz@poppyrecords.invalid.invalid>,
    Liz Tuddenham <liz@poppyrecords.invalid.invalid> scribeth thus
    tony sayer <tony@bancom.co.uk> wrote:

    [...]
    Theres a community radio station here in Cambridge they used to have an
    outfit called the "shellac collective" to be a member i think you had to
    possess an EMT turntable else you were a non entity!.

    I have serviced an EMT for a transcription engineer but could never
    afford one myself. There are several turntables of quality which is >comparable in most aspects except for rumble. A lot of broadcast EMTs
    were fitted with an SME arm - but the whole radial arm business is
    inherently flawed and the biggest improvement is to be had by replacing
    it with a parallel-tracking arm..

    And i suggested one night that they ought to put their programme on a SD card...

    Almost got lynched!..



    One of they did have an Edison phonograph that was or could be miked up
    that did sound surprisingly good!...

    If you hear one in good condition playing unworn cylinders, it is quite >amazing how good they are.


    Indeed Analogue from beginning to end;)...

    Question.. How did they duplicate them from what "Master" recording were
    they from?.

    Or was it just a one time recording?..
    --
    Tony Sayer


    Man is least himself when he talks in his own person.

    Give him a keyboard, and he will reveal himself.


    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From liz@liz@poppyrecords.invalid.invalid (Liz Tuddenham) to uk.tech.broadcast on Mon Aug 11 21:17:28 2025
    From Newsgroup: uk.tech.broadcast

    tony sayer <tony@bancom.co.uk> wrote:

    [...]
    One of they did have an Edison phonograph that was or could be miked up
    that did sound surprisingly good!...

    If you hear one in good condition playing unworn cylinders, it is quite >amazing how good they are.


    Indeed Analogue from beginning to end;)...

    Question.. How did they duplicate them from what "Master" recording were
    they from?.

    Or was it just a one time recording?..

    In the early days each cylinder was recorded individually; the performer
    had to stand in front of an array of recording horns and perform the
    same piece over and over again.

    Edison then invented the "Gold Moulded" method of duplicating them. He suspended the master recording inside an evacuated bell jsr, hanging
    from a bearing and rotated by a magnet on the outside. A high voltage
    trembler coil was connected to a piece of gold leaf to sputter the gold
    onto the surface of the cylinder.

    When the surface of the cylinder was sufficiently conductive, it was
    placed in a plating bath and heavily copper plated. The wax was melted
    out and the copper mould was then used to produce copies. Cylinder wax
    has a large temperature coefficient of expansion, so the copies shrank
    as they cooled and could be removed from the moulds. (They were also
    slightly tapered to assist removal.)

    The recording machine had a non-standard leadscrew that produced a
    master which had the grooves spaced by slightly more than the normal
    pitch. When the wax copies cooled, they shrank to the correct pitch.

    Later cylinders were duplicated in a cellulose nitrate compound which
    was mechanically much stronger than wax, so they bounced if they were
    dropped and could be played many hundreds of times before they wore out. Lengths of thin-walled tubing were placed inside the mould and end caps
    held on while the mould was pressurised with steam. The nitrate tube
    softened and was pressed against the inside of the mould by steam
    pressure. It took up the impression of the original groove (now
    represented as ridges) and shrunk away from the mould when it cooled.

    Unfortunately most of the "Blue Ambrols" made from this superior
    material are actually acoustic dubbings, so the quality is not the best
    that they were capable of.
    --
    ~ Liz Tuddenham ~
    (Remove the ".invalid"s and add ".co.uk" to reply)
    www.poppyrecords.co.uk
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  • From Paul Ratcliffe@abuse@orac12.clara34.co56.uk78 to uk.tech.broadcast on Thu Oct 2 14:06:10 2025
    From Newsgroup: uk.tech.broadcast

    On Sun, 27 Jul 2025 15:38:22 +0100, J. P. Gilliver <G6JPG@255soft.uk>
    wrote:

    On 2025/7/27 13:18:29, Paul Ratcliffe wrote:
    On Tue, 22 Jul 2025 19:09:53 +0100, John Williamson
    <johnwilliamson@btinternet.com> wrote:

    A combination of analogue and digital problems that is going to lose us a >>> lot of important master tapes on Betamax cassettes in that there are not >>> enough tape heads left in the world to play them all back and recover
    the data. More can be made, but the cost would be ridiculous.

    Who stores master tapes on Betamax? Like nobody, ever.
    It was a domestic format. Maybe you were thinking of BetaCam?
    But that wasn't really a format used for 'proper programmes' for
    very long.

    In the early days of digital audio, a means was devised to convert the digital bit-stream into a video signal; it was sufficiently
    low-bandwidth that a domestic video recorder could easily handle it, and indeed domestic videocassettes were indeed used, for example to transfer
    data losslessly between studios of the same company (e. g. between
    mixes, and/or adding artists who were physically in different
    locations).

    Yeah, I know. We used to use the Sony F1 over analogue microwave links
    to get stereo radio programmes from OB site to studio centre (so typically
    for R3).
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