The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure >everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low >voltage transistors makes a better regulator than you could get with
tubes alone. The PSRR is not too shabby for the parts count, better than
you could do with the two other triodes in a traditional diff pair and
then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if
you stick the optocoupler and transistors underneath the compactron (it
gets toasty) your regulator is now also "thermally compensated"!
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure
everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low
voltage transistors makes a better regulator than you could get with
tubes alone. The PSRR is not too shabby for the parts count, better than
you could do with the two other triodes in a traditional diff pair and
then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if
you stick the optocoupler and transistors underneath the compactron (it
gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp
burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
On 12/28/2025 10:01 PM, john larkin wrote:
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
<https://imgur.com/a/EteSbOv>
<https://imgur.com/a/7FzPcWQ>
<https://imgur.com/a/Rba3cgi>
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure >everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low >voltage transistors makes a better regulator than you could get with
tubes alone. The PSRR is not too shabby for the parts count, better than >you could do with the two other triodes in a traditional diff pair and
then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if
you stick the optocoupler and transistors underneath the compactron (it >gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp
burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
On 12/28/2025 10:01 PM, john larkin wrote:
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure >>> everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low
voltage transistors makes a better regulator than you could get with
tubes alone. The PSRR is not too shabby for the parts count, better than >>> you could do with the two other triodes in a traditional diff pair and
then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if
you stick the optocoupler and transistors underneath the compactron (it
gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp
burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
The 6AC10 is an adorable lil tube, mine's Raytheon-branded but made in >Japan:
<https://imgur.com/a/7FzPcWQ>
I don't really have a use for the "funky regulator" but I like the idea
of using an optocoupler to provide drive for the pass element of a HV >regulator, avoiding high voltage transistors or having to float op amps
and such.
I have one "tube bin" with some random stuff like the 6AC10 and some 12
volt tubes in it, even a Strobotron...at some point I inherited a couple >packs of 0B2 gas diodes.
Amazon/eBay sell these little boost modules for tube experimenters with
a HV output and a 6.3 volt output maybe good for an amp or so, they
really hate driving a gas tube directly as a load and the 0B2 flickers
like a neon Christmas candle, some nice noise/chaos on the 'scope too:
<https://imgur.com/a/Rba3cgi>
john larkin <jl@glen--canyon.com> wrote:
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure
everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low
voltage transistors makes a better regulator than you could get with
tubes alone. The PSRR is not too shabby for the parts count, better than
you could do with the two other triodes in a traditional diff pair and
then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if
you stick the optocoupler and transistors underneath the compactron (it
gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp
burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
It was a very long time before the performance of transistors caught up
with Nuvistors. In high radiation and EMP situations, I don't think
they have yet.
Before transistors began to compete, valves for car radios used +12 on
the anodes but they also used either 0v on the first grids to assist the >electrons out of the cathode or +12v to drag them out.
In outer space, where the vacuum is 'perfect' and solar radiation could
be directed onto a sheet cathode, new types of valve might begin to make >sense.
On Mon, 29 Dec 2025 11:52:28 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure >>>> everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low
voltage transistors makes a better regulator than you could get with
tubes alone. The PSRR is not too shabby for the parts count, better than >>>> you could do with the two other triodes in a traditional diff pair and >>>> then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if
you stick the optocoupler and transistors underneath the compactron (it >>>> gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp
burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
It was a very long time before the performance of transistors caught up
with Nuvistors. In high radiation and EMP situations, I don't think
they have yet.
Before transistors began to compete, valves for car radios used +12 on
the anodes but they also used either 0v on the first grids to assist the
electrons out of the cathode or +12v to drag them out.
In outer space, where the vacuum is 'perfect' and solar radiation could
be directed onto a sheet cathode, new types of valve might begin to make
sense.
Philo Farnsworth was a cool guy. He invented the image dissector tube,
the Farnsworth Fusor, and did some interesting multipactor work.
The perfect vacuum in space has some hazards to power RF circuits that
you don't get here.
I think he invented the microchannel plate too.
On 30/12/2025 2:58 am, john larkin wrote:
On Mon, 29 Dec 2025 11:52:28 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote:
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure >>>>> everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low >>>>> voltage transistors makes a better regulator than you could get with >>>>> tubes alone. The PSRR is not too shabby for the parts count, better than >>>>> you could do with the two other triodes in a traditional diff pair and >>>>> then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if >>>>> you stick the optocoupler and transistors underneath the compactron (it >>>>> gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp
burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
It was a very long time before the performance of transistors caught up
with Nuvistors. In high radiation and EMP situations, I don't think
they have yet.
Before transistors began to compete, valves for car radios used +12 on
the anodes but they also used either 0v on the first grids to assist the >>> electrons out of the cathode or +12v to drag them out.
In outer space, where the vacuum is 'perfect' and solar radiation could
be directed onto a sheet cathode, new types of valve might begin to make >>> sense.
Philo Farnsworth was a cool guy. He invented the image dissector tube,
the Farnsworth Fusor, and did some interesting multipactor work.
The perfect vacuum in space has some hazards to power RF circuits that
you don't get here.
I think he invented the microchannel plate too.
Seems unlikely.
https://apps.dtic.mil/sti/tr/pdf/ADA195556.pdf
"The concept of a continous channel electron multiplier was developed
near the end of 1950. The invention was that of G.W. Goodrich of the >Research Laboratories Division, Bendix Corporation."
The original application was for night vision googles. Cambridge
Instruments used them as electron multipliers in their electron beam >microfabricators. They had to be replaced every six months, but that was >tolerable with a million dollar machine.
On Wed, 31 Dec 2025 00:36:38 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 30/12/2025 2:58 am, john larkin wrote:
On Mon, 29 Dec 2025 11:52:28 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sun, 28 Dec 2025 14:23:50 -0500, bitrex <user@example.net> wrote: >>>>>
The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure >>>>>> everyone has one of those in their junk box..
But the transconductance of a triode is wussy, so adding a couple low >>>>>> voltage transistors makes a better regulator than you could get with >>>>>> tubes alone. The PSRR is not too shabby for the parts count, better than >>>>>> you could do with the two other triodes in a traditional diff pair and >>>>>> then you'd want a current source for the pair and bla bla bla.
<https://imgur.com/a/EteSbOv>
You could use an 0B2 for the Zener for that real vintage feel. And if >>>>>> you stick the optocoupler and transistors underneath the compactron (it >>>>>> gets toasty) your regulator is now also "thermally compensated"!
When transistors were just becoming affordable, there was a last-gasp >>>>> burst of effort to save the tube industry. There were compactrons,
nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.
It was a very long time before the performance of transistors caught up >>>> with Nuvistors. In high radiation and EMP situations, I don't think
they have yet.
Before transistors began to compete, valves for car radios used +12 on >>>> the anodes but they also used either 0v on the first grids to assist the >>>> electrons out of the cathode or +12v to drag them out.
In outer space, where the vacuum is 'perfect' and solar radiation could >>>> be directed onto a sheet cathode, new types of valve might begin to make >>>> sense.
Philo Farnsworth was a cool guy. He invented the image dissector tube,
the Farnsworth Fusor, and did some interesting multipactor work.
The perfect vacuum in space has some hazards to power RF circuits that
you don't get here.
I think he invented the microchannel plate too.
Seems unlikely.
https://apps.dtic.mil/sti/tr/pdf/ADA195556.pdf
"The concept of a continous channel electron multiplier was developed
near the end of 1950. The invention was that of G.W. Goodrich of the
Research Laboratories Division, Bendix Corporation."
The original application was for night vision googles. Cambridge
Instruments used them as electron multipliers in their electron beam
microfabricators. They had to be replaced every six months, but that was
tolerable with a million dollar machine.
This is what google says:
AI Overview
The concept of the continuous channel electron multiplier, or
continuous dynode, was first proposed by American physicist
Philo T. Farnsworth in 1930,
with early prototypes and active
development occurring in the 1960s, particularly with work by Russian scientists like I. Pesyatsky and later commercialized into
microchannel plates (MCPs).
Key Contributions:
Philo T. Farnsworth (1930s): Proposed the fundamental idea of
using a continuous, hollow resistor coated with secondary-emissive
material to amplify electrons.
I. Pesyatsky (1940s): Created one of the first working prototypes
of the microchannel plate (MCP) structure.
1960s Development: Significant technological advancements by
various groups led to the modern microchannel plate, a matrix of these continuous dynode channels, as described in this University of Chicago
PDF and this ScienceDirect article
Philo also achieved nuclear fusion around 1965.
https://en.wikipedia.org/wiki/Fusor#History
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