In my experience, it is not difficult to source either. Both the Vanderveen unity coupled OPTs and the Chinese MC275 clones are excellent, in my experience, as shown in the links above at Audiokarma. Either will run $600 or so for the pair.
As far as cathode feedback transformers, Toroidy has several to choose from. Here is one. They can be had for much less money.
https://sklep.toroidy.pl/en_US/p/-T...nsformer-5kOhm-Cathode-Feedback-Push-pull/659
As far as cathode feedback transformers, Toroidy has several to choose from. Here is one. They can be had for much less money.
https://sklep.toroidy.pl/en_US/p/-T...nsformer-5kOhm-Cathode-Feedback-Push-pull/659
I also think of Yves, owner and founder of Dissident Audio.
he makes excellent custom-made output transformers and is a fan of distributed charging.
he makes excellent custom-made output transformers and is a fan of distributed charging.
However well wound the Unity Coupled substitutes are, you may have to adjust the global negative feedback compensation.
And be prepared to use bootstrapping for the drivers (Bootstrapping in the form of Positive feedback, by the way).
Did you ever build a 3 transistor amplifier with complementary output transistors (NPN and PNP as emitter followers), and that bootstrapped the driver collector load resistor from the output signal? . . . I did!
Ooops! Solid State subject in the Tubes / Valves threads.
And be prepared to use bootstrapping for the drivers (Bootstrapping in the form of Positive feedback, by the way).
Did you ever build a 3 transistor amplifier with complementary output transistors (NPN and PNP as emitter followers), and that bootstrapped the driver collector load resistor from the output signal? . . . I did!
Ooops! Solid State subject in the Tubes / Valves threads.
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