Hello!!!
I bought this amp used, it's manufactured on early 90's I think.
When I first powered it, I noticed that:
1- It's a loud amp. I mean LOUD! Also get a huge volume jump only touching the volume knob a bit, making it difficult to find any "in between" settings - and I live in a apartment, which makes this a real issue...
2- The controls were scratchy as hell.
3- When reverb is on, it "humms" a lot.
4- When switched OFF it makes such a loud POP, whatever the volume is at the time. I mean, the first time this happened I almos had a heart atack!! Scared th $hit out of me and my cat! Never saw him running so fast to hide under the bed.
I already took apart the amp to check values and components with the help of official schematic (
support.fender.com/schematics/guitar_amplifiers/Roc_Pro_1000_schematic.pdf).
This is what I found/did:
- All the traces and solder points seemed OK. Nonetheless I did some resoldering/reflowing on valve socket, input/output jacks, opamp pins and everything else I felt could be "better" soldered, just to make sure...
- No leaking/swollen electrolitics, no burnouts below power resitors also. I measured the cap values, namely C71-72-73-74 and they are reading ok.
- Sprayed the pots, jacks, switches (including ON/OFF switch and reverb connectors) and valve socket with contact cleaner.
- Changed the tube for a lower gain JJ 5751.
- Also noticed that the Volume Pots are log type (A), so my idea of changing them for this type so the volume could be more smooth and controlable is out the window...
Now, after all this done, I reassembled the amp and the shutoff POP is still present (my cat is also hiding everytime I get close to this amp
)!
The reverb "hummm" is still there also.
Good news is that control pots "scratchiness" is GONE.
Now, please I need more advices.
- what else could I check??
- can I sub the A50K volume pots to say A500K and expect to get a smoother volume raise?
Thank you so much for your time!
Cheers!!