1984 JCM 800 2205 REVERB ISSUE

John.B

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I wonder if anyone has any advice for me.
My JCM 800's reverb has an intermittent fault, it's been like it since 1984 when I bought it. Typically, if the amp is with a tech, it works perfectly, but every now and then it makes a dreadful screachy feedbacky type of noise which can be turned down by turning off the reverb. This can sometimes be cured by gently lifting and dropping the amp almost as if the springs were caught up.
Would a new tank solve this issue and if so can anyone recommend a suitable replacement tank. I'm in the UK.
Any advice would be greatfully appreciated.
Thanks
 

Gunner64

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Try cleaning the reverb driver tube socket. You can gently tap the tube with a pencil or the like to see if it makes the noise your experiencing.

My reverb made some nasty noises as well, and cleaning that socket was the solutuon.
 

John.B

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Thank you for this sensible advice. I will give them both a go and let you know how it goes.
 

John.B

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Try cleaning the reverb driver tube socket. You can gently tap the tube with a pencil or the like to see if it makes the noise your experiencing.

My reverb made some nasty noises as well, and cleaning that socket was the solutuon.
Which tube is the reverb driver?
 

Clayton Custom Cabs

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I'm guessing it is flaky ground connections at the RCA connectors on the tank itself. Try spraying them with DeOxit.
By coincidence I had a CRATE VC3112 on my bench this week for recapping and when I got it running again I plugged in the reverb tank and it did exactly as you described - screaching loudly. It went away when I unplugged and then replugged the input. My guess is a faulty ground as was noted by someone else.
 


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