Reverb/Noise issues on Silverface Princeton Reverb

[royforever]

Hi guys,

' hope you will be able to help me out with this !


I have just received a 74' Silverface Princeton Reverb and I have been experiencing the following issues:

1. No reverb can be heard (whether set at 1 or 10)
2. Annoying Fuzzy/light overdride sound starting even at low volume (2-3)
3. Weak output power/headroom

My guess is that all these issues are reverb related...
I have checked connections, the reverb tube might be dead (how can I easily check this ? No glowing ?) or a ground wire has been disconnected during the shipping...

Do you have any ideas ?

Thanks for your help,
Franck

[pontiacpete]

I'd try it without the reverb unit connected, see how it sounds.

[royforever]

Hi Pontiac,

I tried it already and I still have the issue with the fuzzy sound...


Roy

[pontiacpete]

there are several 7025/12ax7's that you can try exchanging there places, see if that helps. You need to get a few known working pre amp tubes 12at7's and 12ax7's to swap in there.
I would change out paper caps, and most likely the can if it hadn't been done already.
pete

[royforever]

Hello,

Thanks for your help !


I have already tried to switch the tubes but it had no impact on the fuzz...
I should have someone look into it and see if there's no wire disconnected.

If you have another idea...


Roy

[pontiacpete]

Are you 6V6 power tubes ok?
I would unplug, take the chassis out, discharge caps and do some resistance checks, with the amp off. If the electrolytic cap in the bias supply 50uf/70v is the original, I would be changed it, 47/100 is what I have in mine. I also just changed out all the 25/25's on the board.
pete

[royforever]

Hi Pete,

I don't feel quite comfortable opening up the beast !

How much do you think it would cost to have it checked by a tech ?

Cheers,
Franck

[pontiacpete]

It depends on how much work is involved. Initial bench charge around here starts at around $75.
might not be much more than that.
pete