Current feedback Mosfet Circlotron

10X fqp3n30 have lower input capacitance than only one IRFP150N but better transconductance, so the result is not the same.

simulation shows in the performance of the amp, lower distortion, lower current on driver at high frequency

Yes, I've measured a few samples, actual values in this thread. Matching is pretty good out of the tube also.

Assorted Pulsed transistor measurements
 
Amplifier spectra with unbalanced input connection.
 

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I bump into Joe Berry's latest schematics by chance, and find it quite interesting :
https://www.diyaudio.com/community/threads/joe-berrys-circlotron.384070/post-6974724

After taking some time to understand how it works, I was not entirely happy with the high H3 in the simulation.
So I tried a few things, including using all Toshiba active devices, and rich Class A bias.
The improvement is not insignificant.

Only simulations of course.


Best Regards,
Patrick

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