Hey guys. So I just scored a jcm800 2210 with a jcm900 cab today for $900. Cab was all kinds of wired wrong, so I fixed that. And the head sounds good, but I have this annoying buzz on the lead channel only. If I put the lead channel volume and gain both at noon, the buzzing is at a minimum. The other weird thing is if I switch off the lead channel and then switch it back on and don’t play anything, the buzz is gone. The minute I play anything however, the buzz is back. I have tried other outlets thinking maybe it was that, turned all my lights off in my room. Nope. Swapped both preamp and power tubes and no change. The other weird thing is the reverb tank is gone and the tube for the reverb was pulled. So I connected a reverb tank I have from my tsl, and put the tube in, and the reverb doesn’t work either lol. Just an even louder buzz when turning the reverb knob. Again the amp sounds awesome, just want to get rid of the buzz on the lead channel. Any ideas? Thanks I’m advance everyone!
Marshall 2210 buzz on lead channel
- Thread starter vscrl1
- Start date
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I just saw this video that @Weapons Man posted in another thread. This tech was looking to solve a hum in the 50w version of your amp. Turned out to be a bad ground.
One thing to keep in mind is that the reverb in a TSL is driven by op amps, while the 2210’s reverb is tube and transformer driven. So the tank for the 2210 probably has a different impedance than the tank used in the TSL. That said, I imagine you’d still get some reverb sound if the circuit was working.
Pete Farrington
Well-Known Member
The design of the 2205 / 2210 changed significantly in the mid 80s. To identify which version it is, photos of the board would be helpful, or just check whether it has a CA3046 switching chip.
As noted, neither version will work well with a TSL reverb tank.
As noted, neither version will work well with a TSL reverb tank.
Pete Farrington
Well-Known Member
I’m not sure exactly when things changed, but your’s is most probably the earlier version
I suggest to try replacing the rectifier diodes and power supply ecaps for the switching circuit. Use beefier diodes than the ratty little 1N914 noted on the schematic, eg 1N4007.
The design of the switching supply and switching circuit makes it liable to damage when an output valve shorts.
I suggest to try replacing the rectifier diodes and power supply ecaps for the switching circuit. Use beefier diodes than the ratty little 1N914 noted on the schematic, eg 1N4007.
The design of the switching supply and switching circuit makes it liable to damage when an output valve shorts.
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The schematic says 4FB2A1C for the reverb tank. Google that number and the proper Accutronics tank should come up.
I found this:
https://www.amprepairparts.com/reverb.htm
https://www.amprepairparts.com/reverb.htm
