Fender Red Knob Twin reverb operation

[jalexquijano]

i recently noticed that although the reverb on my 1990 Fender The Twin aka Red Knob Works, it starts working when i dial the 100k reverb pot to 3. Is this normal or could a resistor in the circuit be worn due to the age of this amp? Comparing it to a Supersonic Twin or a Twin reverb 65 reissue, the reverb operates immediately when you dial the pot to 1.

[Mick Bailey]

Different amps do different things. There are so many stacked variables involved that even when comparing amps of the same model from the same production batch you get differences. Comparing your amp to a different model is even more likely to show up differences.

Resistors don't really wear. You could maybe get some nominal drift in value, or just become aware of the expected tolerance, but a resistor is more likely to by either OK or open.

If you do want to check it out further, make sure the cables to the reverb tray haven't gone high-resistance, and your plugs and RCA sockets are making good contact.

[g1]

Have you checked the pot with an ohm meter to see that the pot is working through it's whole travel?
You mentioned in your other posts that the volume pots are not going to zero either.
Have you cleaned all the pots with something like de-oxit?

[jalexquijano]

Ill try spraying some deoxit today on each of the pots holes. Pitty i will need to dissasemble that PCB again to service them. I also noticed that if i tun the reverb pot over 7 it starts to produce some feedback. any clues?

[Enzo]

it is also quite possible you are experiencing crosstalk, rather than control problems.

[g1]

Remove the tank bag from the back of the cabinet and position it as far away as the cables allow. Does it still feed back above 7 ?

[jalexquijano]

ill try this also!

[Mick Bailey]

Be careful not to confuse a characteristic of a particular amp with a fault.