Hi guys,
I have a Roland jc-120 and am having a few problems with it. The chorus effect seems to be stuck on one setting and the knobs wont change the sound. The same knobs control the vibrato perfectly fine. Also when i turn up the reverb a buz starts to occur and increases with the amount of reverb added. Any help will b greatly appreciated. Cheers,Mike.

Sounds like a bad solder connection inside the amp. I'd take it to a repair shop.

Regarding the chorus, the JC-120 is supposed to be that way. With the switch in chorus mode, it is preset. In Vibrato mode, it really is just a manual chorus.

The reverb issue is something else though...

They are noisy amps.

Roger