Hi,
Thanks for your answers !
Then what about increasing the power rating of the circuit ? I'll order a custum made trafo anyway (I have already some trafos I have to order there so I'll buy this one in a row).
I'm not that interested in burning in tubes one by one (but still interested in understanding things), but I often need to test high power tubes like 6550 or KT88.
So I'll think about modding the circuit :
- increase the voltage and current capabilities of the trafo
- find some transistors that can replace the MPSA92, BUZ80/IRF830, MPSA42
- deport them outside the PCB and stick them on huge radiators
- use higher voltage rating caps in the B+/screen circuit
- replace the ZD1-7 zeners to get 550-600V at the HV regulator
- check if the available BIAS voltage is low enough for those power tubes
- check if the heater current capacity is high enough
- etc.
That'll take quite a lot of time
I'll come back here with a mod proposal, to get some opinions and share it, because I think I'm not the only guitar amp tech interested in that circuit !
To be continued.
Best regards.
Eric