30Hz seems to be OK just about full power 80V ppk. 20Hz power is 3dB down. Therefore sounds OK with the 1650M, will add a input HPF to cut in a little. Plan would be to pair them up with some mid range small floor standing speakers so these with be down at 40Hz.
Toroidy makes an interesting transformer https://sklep.toroidy.pl/en_US/p/TT...rmer-1,2kOhm-2x6C33C-Push-pull-or-similar/565
Any details on what wattage resistor and zener you're using? Did you just make another divider off the 12 for the .4?
This is the KT88 design which is similar but with lower voltage transistors. You want high HFE PNP. The 100K is 2W. Q4 allows you to hold off the bias until the tubes are warm. I saw the toroidy did not look there. 1k2 may give you most drive at about 6R which is good for many floor standers which often contain 2 bass drivers in parallel. Looking for better sockets for the 6c33, the ceramic base ones I have the tubes drop out of.
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baudouino,
At what Post # did we shift from 6C33 to KT88?
Are you merely posting a topology that works for KT88 tubes, that only needs higher voltage transistors to make it work with the 6C33 tubes?
Thanks!
At what Post # did we shift from 6C33 to KT88?
Are you merely posting a topology that works for KT88 tubes, that only needs higher voltage transistors to make it work with the 6C33 tubes?
Thanks!