The Amp Garage

The problem is pretty obvious just by looking at the measured voltages. Screen voltage is ≈ 320V and bias voltage on control grid ≈ -12V. Under these conditions each 6V6 is drawing maybe 80mA, no wonder the B+ is sagging so low with power transformer with secondary rated "650/550Vct @ 100 mA". Now y...

smps means switch mode power supply. I don't think you'd want one in a tube amp. they work in really high frequencies but might not be the best for tubes, I think they prefer linear power supplies no? Tubes don't care if you make DC from 50 Hz or 200 kHz. If I want DC supply for heaters I almost al...

Do you recall what your B+ was coming out of your rectifier diodes/at R39? As I recall in my amp B+ is about 390V. For anyone building this what your B+ voltage is going to be is going to depend on the power transformer you use, but B+ anywhere between 350V - 420V should be fine. If it's in that ra...

What is R39 for and what do you have in there? R39 is optional "sag" resistor. You can put put 50 - 100 ohm 10W resistor there or if you don't want to use it just put a jumper over it or put stand by switch there like you did. I used NTC thermistor there as R39 to limit inrush current so I don't bl...

Guy77 wrote: ↑Sat Jul 04, 2020 1:58 pm How do the preamp tubes plug into your board? Is there a special socket .

Noval PCB socket

I recently made a Princeton Reverb with couple minor tweaks. Here are the gerber files for the pcb if anyone wants to use them. http://ghr.fi/guitaramps/trinceton/princetonreverbo350x110.zip Schematic and layout attached Here is a sound sample we recorded: http://ghr.fi/guitaramps/trinceton/trinceto...

The big Miflex cap is the bias cap (C22). I happened to have one 10u Miflex polypropylene cap so I used it instead of the 22u electrolytic marked on the schematic.

I used the stock tube symbols for the schematic and the noval footprint for the pcb is this

I recently built Princeton Reverb with few minor tweaks. Tremolo can be quite weak in Princeton so I changed the 1M resistor that couples the oscillator to the bias pot to 220k (R33 in my schematic). I would not bother with DC heaters. With "low-gain" amp like Princeton decent lead dress and layout ...