A few years ago I was doing a search and came across an interesting amp, but I can't remember it now. It is a lab/instrument grade power amp, possibly made in the 60s. I do remember that it has fairly high power and according to the specs, an absurdly high amount of NFB. The schematic showed an equally ridiculous amount of circuit complexity.
The manufacturer is/was not (to me) a well known name, either from the instrumentation or audio businesses. Does it ring a bell for anyone?
The manufacturer is/was not (to me) a well known name, either from the instrumentation or audio businesses. Does it ring a bell for anyone?
I assume you are thinking of Dick Burwen and the Krohn-Hite UF-101 power amplifier?
http://www.burwenaudio.com/Krohn-Hite_UF-101.pdf
http://www.burwenaudio.com/Krohn-Hite_UF-101.pdf
Thanks Kevin, no. It was not from a manufacturer as well known as Krohn-Hite. It had similarly high NFB but it was very complex with many tubes reminiscent of some of the most complex AR designs.
Tektronix definitely no, it wasn't from a well known manufacturer. Wollcott possibly, do you have a schematic and/or other info on it?
I do vaguely remember it was intended more as a lab instrument, not a high end audio piece. Similar to what you would find from Krohn-Hite or Bruel & Kjaer but from a lesser known manufacturer.
I do vaguely remember it was intended more as a lab instrument, not a high end audio piece. Similar to what you would find from Krohn-Hite or Bruel & Kjaer but from a lesser known manufacturer.
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I think you meant the JBL PL-100 designed by Henry Wolcott in 1960.
Dick Olsher: Wolcott Audio ?Presence? Monoblock Tube Amplifier
Tube Amplifiers - Vacuum Tube Amplifiers - Loudspeakers - Wolcott Audio Research
Yeah, Optimation PA-250. A Wollcott design.
Schematics in the linked thread.
Another unusual amp was a calibration Amp by Fluke. Don't recall the model # off hand, maybe the 5205A Precision Power Amplifier. Has a warm up for the tubes. 120 Lbs. 0.05% dist. DC to 100 KHz.
Schematics in the linked thread.
Another unusual amp was a calibration Amp by Fluke. Don't recall the model # off hand, maybe the 5205A Precision Power Amplifier. Has a warm up for the tubes. 120 Lbs. 0.05% dist. DC to 100 KHz.
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It may have been the Wolcott/Optimation, but I remember it being more complex, lots of tubes. Not just the power tubes. Could be my memory is not accurate.
More complex?
Here it is, by Osvaldo de Banfield, one of our members:
https://www.diyaudio.com/forums/tubes-valves/341298-tube-amp-coupling-capacitors-5.html#post5881388
Then some others (OTL)
Here it is, by Osvaldo de Banfield, one of our members:
https://www.diyaudio.com/forums/tubes-valves/341298-tube-amp-coupling-capacitors-5.html#post5881388
Then some others (OTL)
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