JCM800 4210/2205 Bright Cap Mod

Amplifiers contain voltages high enough to Kill you even after the amp has been powered Off !!! If you don't have enough electronic experience to identify and discharge the Filter Capacitors which contain these Deadly voltages, take your amp to a Qualified tech. If you don't know a qualified tech in your area, post a request in the alt.guitar. amps newsgroup, the folks there will be happy to help you.

The Mod:

There's a lot of discussion in regard to the so called bright caps in JCM800's. If the JCM800 is too harsh for your particular tastes, the following details a few simple changes to remedy this for you.

1. If it's the rhythm channel, snip out C3.


2. If it's the lead channel, change C7 from a .002 uf to a .022 uf.


3. If it's BOTH channels, try putting a higher value cap across R47 to unbrighten "both" channels.