Do anybody experimented or work around Operational Amplifiers made only with vacuum tubes/valves (No ss at all)?
I have some ideas, but mu brain is open to newer/different ones. What I need is a differential triode/pentode pair wit inverting and noninverting inputs, one or two inverted outputs.
Any suggestion or example is welcomed.
I have some ideas, but mu brain is open to newer/different ones. What I need is a differential triode/pentode pair wit inverting and noninverting inputs, one or two inverted outputs.
Any suggestion or example is welcomed.
Thanks, Paul. I read something about it, but my doubt are the neon lamps in the signal path. Aren't they noisier?
I want to make 3 units to extrapolate an invention of a guy I know into the tube technology, he did it using SS and works pretty fine. By the moment, I reserve the basic idea of the thing.
My current idea is as follows: a (not exactly) differential pair made with a triode and a pentode inside the 8BU11 compactron tube. The last triode as a follower for the output. This tube with filaments grounded at 0VDC. A 6U8 tube, with the pentode as CCS for the pair, an the triode as CCS for the output triode. A neon lamp to give biasing for both CCS, with heaters near the negative rail (I called it Ekk).
I want to make 3 units to extrapolate an invention of a guy I know into the tube technology, he did it using SS and works pretty fine. By the moment, I reserve the basic idea of the thing.
My current idea is as follows: a (not exactly) differential pair made with a triode and a pentode inside the 8BU11 compactron tube. The last triode as a follower for the output. This tube with filaments grounded at 0VDC. A 6U8 tube, with the pentode as CCS for the pair, an the triode as CCS for the output triode. A neon lamp to give biasing for both CCS, with heaters near the negative rail (I called it Ekk).
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I think that the first question is why do you desire an op-amp, whether tube or transistor? What is the application?
Interesting readings.
The purpose: a novel sine wave RC oscillator that uses no classical frequency selective networks. As it isn't my idea, I still can't give further details.
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The project resembles this, but it is not equal to the showed below. It uses different array of passive elements. Nor it is of the Bubba topology.
Sorry, I still have no permission to give more details, because it is under development and perhaps it will be patented. It has been designed in the Campus of an University in Argentina and I am not the creator. Only a second test of the principle.
Sorry, I still have no permission to give more details, because it is under development and perhaps it will be patented. It has been designed in the Campus of an University in Argentina and I am not the creator. Only a second test of the principle.
if it is a true op-amp then the negative feedback required to reduce the gain to 10 will increase linearity to the point where it sounds solid state, so why bother.
properly used solid state parts increase the sonic performance of a tube amplifier
properly used solid state parts increase the sonic performance of a tube amplifier
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my doubt are the neon lamps in the signal path. Aren't they noisier?
They're not in the signal path, they're over-voltage protection clamps.
I spent many hours on this one solving differential equations. Probably it helped me a lot later to design things with nested feedbacks. ;-)
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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I think there is one on Nelson Pass "passdiy" site. Go to "projects" and hit "amplifiers" then on the Project categories list on the left hand side a number of articles will emerge. About a third of the way down. It is called "DIY op amps"
It is a 2 tube simple opamp. 12 AX7 I think.
Cheers
Jonathan
It is a 2 tube simple opamp. 12 AX7 I think.
Cheers
Jonathan
There was the Heathkit EC-1 home analog computer.
Then some VT Op Amp circuits from the book "Analogue and Hybrid Computers" by Z. Nenadal and B. Mirtes 1962
Heathkit EC-1 manual:
http://www.analogmuseum.org/library/heathkit_ec1_operation_manual.pdf
There is a more complex Heathkit Analog Computer, the H-1 too:
Heath H-1 Analog Computer - neurotica.com
and the VT Op Amp for the H-1:
D. C. Amplifier ES-201 Misc Heathkit Brand, Heath Co.; Bento
..
Then some VT Op Amp circuits from the book "Analogue and Hybrid Computers" by Z. Nenadal and B. Mirtes 1962
Heathkit EC-1 manual:
http://www.analogmuseum.org/library/heathkit_ec1_operation_manual.pdf
There is a more complex Heathkit Analog Computer, the H-1 too:
Heath H-1 Analog Computer - neurotica.com
and the VT Op Amp for the H-1:
D. C. Amplifier ES-201 Misc Heathkit Brand, Heath Co.; Bento
..
Attachments
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The Heathkit ES-201 OP Amplifier schematic (for the H-1 Analog Computer):
Attachments
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Then there was the Tektronix Type "O" plug-in. A VT dual OP Amp. scope plug-in. I still have one of these around, nice for an integrator for xfmr. hysteresis curves.
O - TekWiki
O - TekWiki
Interesting apparatus. Call my attention the lighter, did you want to put it on fire? 🙂
Smoking amp: There was an analog computer like the one in the last pic, in the University I coursed my studies. They destroyed completely, because the chief of the cathedra didn't know what the thing was.