The Amp Garage

Woohoo! Well I figured out the issue in the preamp, the 100k cathode resistor (R36) on the cathode follower stage before the tone controls was open circuit. I found this almost by sheer chance as I was probing the circuit from the area I found that 1) I had just a few mV on the cathode of the follow...

Cathode biased outputs ride with their grids at a different DC level than fixed bias tubes. Is it possible that the capacitors separating the sets of grids are leaking? Thank you for the response R.G. I am actually using your "quick and less-dirty" oscillator as my test signal! I will look into thi...

Hi all. My friend brought a 2000 VHT Pitbull Hundred/CL with EL34's to me with some kind of volume fluctuation that I have not been able to reproduce. I did, however, find that it was red-plating a bit. The amp has a "dual class" mode via a switch on the back where one tube on each side of the power...

Thanks for the reply @maxkracht. I reflowed all high-mass component solder joints on the power board on Amp A. I am hesitant to remove that big resistor since it’s in there pretty good. I reflowed its connections and it measures fine when hot. I narrowed the sizzle down to the molex connecter for th...

Hi all, started my tube amp journey this year fixing amps for my friends. It’s been a great learning experience and I’m on a winning streak, but my latest two patients have me stumped. Two Peavey VTM-120 of many my friend bought from someone hoarding them have the same issue. He said he was using ea...