The Amp Garage

I have a somewhat good news. The V1 tube has a metal shielding cap that is supposed to be grounded. However it had a bad ground connection (grey wire) to the metal peg ( see photo). I restored the good ground and the hi pitch ocellation went away! Now, i am starting to believe that 12AX7 is too powe...

One more question. Does anyone know what is the purpose of this part on the photo :

Good evening, messieur, to ceramic resistors, if too close to audio signals, can raiming this problem/ HT = oscillation keep it away from the top of the pcb I will look for those ceramic resistors and see how I can isolate them. BTW, what is the location of the resistors that you are talking about?...

I just found that both of my phase shift capacitors (.01) were shorted. I wonder what voltage rating should they have? Update. After the replacement of the failed capacitor is everything started working. Like they say, if the vibrato is not working it’s best to replace bypass capacitor and phase shi...

Sinse I already replaced both bypass caps with the new ones, i decided to inspect the solder joints above and below, but did not see any problems there. Now, though the vibrato intensity pot completely turns off the signal when I turn it all the way to the right ( works like reverce volume pot). I a...

At some point the vibrato effect worked, But now it’s back to slowly dying off after I ground the foot switch. As soon as I grounded the octocoupler oscillates But slowly dies down and the voltage on the pin the one of the V5 tube Starts at 365 then isolates and stops at 212 or so. I replaced .01 ca...

I just wanted to tell you all that putting bothof these primery coils in parallel worked. The node voltages are about 8 Volts or so lower but the amps sounds great and the owner was very happy. I wish the instructions would have been more clear but, oh well, that is why we have one another- to help ...

I have an update. After trying to add 20uf 500V across every filter cap I did not get any improvement. I also replaced very cantankerous 6AN8A tube and removed one ground lead off the dual ones on the guitar plug in jacks ( that go to the grids). I also resoldered the PI tube’s soket and V1 socket. ...

Thanks again for your help. When I measure the voltage on the pin 1 of a V5 tube It shows 365 V. When I ground the vibrato foot switch it drops to 220 V. The voltage on the pin six is 313 V and when I ground the foot switch it goes down to 308.

I have one good news. I found that the reverb output RCA plug was not making a good connection. I replaced it and now I have a strong reverb when you use the Vibrato inputs. Is it normal for this amp not to have the reverb in the Normal input? Everything else seems to be working now but I have a str...

Thank you for your help. I had a chance work on it again today for a little bit. I did a lot of pocking with a bamboo stick and could not find a bad ground or a bad connection. I did find the grid wire coming from an input being grounded on both ends, but fixing this problem did not fix 10k oscillat...

Hello again. I met a guy who asked me to take a look at his Ampeg V4 amp head . He just wanted me to make sure it’s in a good working order. I tested tubes and found one output and one preamp tube that needed replacement – I replace them. I also cleaned potentiometers And checked ESR on the filterin...

When I tried to connect just the coil on top between the violet and black and green wire the voltages Were close to where I needed but it with SAG every time I put a load on it. Just now reconnected black and green Wire with the black and put a neutral wire in it and black and yellow with black and ...

I met a guy today who brought with him from UK a Blues Junior 3 and he asked me if I can help him rewire it to 120V from 230V. I have the manual, that I attached, but it does not really show how to wire it to 120V. I tried wiring for 100V but instead of White wire I connected white/black to the neut...

I found another reverb tank that has the proper model number ( off another twin amp), but the effect is so quet... is it normal for Fender Twin reverb to be so quiet?