I have a PS-2A that gives me almost no/low volume. Double checked connections/wires/etc. AOK. Switch to bypass, get full volume from amp. AOK
I opened it up and looks like the original tubes (Ruby). I’ve had this PS/2 for years. I swapped all the tubes, both 6L6s and the 12AX7, with two diff sets of used tubes. Same result, low/no volume from the unit. The fuse looks good and I obviously get lights on the front of the unit.
Hmm, my used tubes may be bad, but two sets? Before I spring for a whole new set of tubes, any other ideas that may explain the loss of volume here?
Hello, Please detail the setup and connections of your rig. Anything connected to the PS-2’s effects loop? When did the unit last function properly? Did it suddenly develop this issue or did it happen gradually? The answers to these questions will help me with a diagnosis. Thanks! Gil
Using a 1964 Bassman Head/Cab @ 4 ohms
Amp out → ps2 amp in
PS2 spk out → spk cab (4 ohm, impedance select set to 4)
I’m not using the FX loop
this setup worked fine 2-3 days ago then suddenly stopped.
if I flip to bypass, amps sounds fine, clear, loud, as expected. Tells me the cables are OK.
I then tried it with a Marshall Class 5 head/cab @ 8 ohms using diff cables, same results.
I also tried a patch cable from Fx Snd/Rtn and line in/out. No change.
I swapped out the tubes twice and got same results.
Ok, thanks for that info! There is an internal fuse that often blows when the power tubes fail, it is located on the circuit board just beneath the power tubes. It’s probably blown, the correct replacement fuse is;
630mA Fast acting / Fast blow 5mm x 20mm Part number: Littlefuse 0217.630MXP
Another possibility; When you swapped the tubes, did you just swap out the pair of power tubes? Have you tried swapping out the 12AX7 power amp driver/phase inverter tube?
Let me know what you discover. Gil