snapper,
Push Pull with cathode feedback may be popular today.
But it is not "the new concept".
I do not know all of vacuum tube history, but in the early or mid 1950s, McIntosh was one of the companies that used that back then.
Look even earlier than that, and I bet you will find that concept already used.
Push Pull with cathode feedback may be popular today.
But it is not "the new concept".
I do not know all of vacuum tube history, but in the early or mid 1950s, McIntosh was one of the companies that used that back then.
Look even earlier than that, and I bet you will find that concept already used.
Frank McIntosh's and Gordon Gow's Unity Coupling concept is sort of extreme cathode feedback, as the cathode winding of one side and the plate winding of the other one are wound bifilarly. Hence, turns ratio is 1:1. Patented in 1949, it supposedly proceeded the cathode feedback designs with lower turns ratios. According to Morgan Jones, these were intended as an alternative to the usual ultralinear designs, which Unity Coupling certainly isn't.
Best regards!
Best regards!
So who knows when the first push pull non-unity cathode feedback amplifier was produced?
Come on, all you vacuum tube historians, find the answer.
At least I have been reading about non-unity coupled cathode feedback for many decades, both single ended and push pull.
I used it single ended from the 16 Ohm tap, myself in 1996, and I was aware of it being "old" then.
I said it was not a "new concept".
Come on, all you vacuum tube historians, find the answer.
At least I have been reading about non-unity coupled cathode feedback for many decades, both single ended and push pull.
I used it single ended from the 16 Ohm tap, myself in 1996, and I was aware of it being "old" then.
I said it was not a "new concept".
Quad II?
A few years later, in 1953, the product which set the standard for amplifiers was the Quad II Power Amplifier, the time of Queen Elizabeth’s Coronation and the year in which Mount Everest was finally conquered. This amplifier pioneered the principle of cathode coupling through the output transformer to reduce harmonic distortion to almost negligible levels. Such was its clear superiority that this model remained in production for 18 years.
Quad history
A few years later, in 1953, the product which set the standard for amplifiers was the Quad II Power Amplifier, the time of Queen Elizabeth’s Coronation and the year in which Mount Everest was finally conquered. This amplifier pioneered the principle of cathode coupling through the output transformer to reduce harmonic distortion to almost negligible levels. Such was its clear superiority that this model remained in production for 18 years.
Quad history
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If you can get the Toroidy cathode winding transformers that would be your best bet - as its the best match to your original schematic. It may still require adjustment of the NFB.