1989 Marshall JCM 800 2203

The JCM 800 defined hard rock and metal during the 80’s and is one of the most popular and copied designs of all time. It is my personal favorite amp for dirty/distorted sounds. This one came in having power dropping issues and no sound output intermittently. The amp was completely original except for some 1ohm bias resistors improperly installed on the power tube sockets.

The amp was given a full restoration. All the axial lead electrolytic capacitors were replaced with upgraded temperature rated Vishay brand electrolytic’s. The multi-section cap can’s were replaced with new German made F&T 50/50uf 500v type units. The power dropping resistors were upgraded to 3 watt Metal Film type, and 5 watt Cement type for the Screen Grid's - This was done for better noise floor and reliability. Also the Screen Grid Resistors showed signs of heat damage.

The amp was completely re-tubed with the following compliment. V1 = EHX 12AX7 GOLD, V2/V3 = EHX 12AX7, V4-V7 = Tungsol EL34B Matched Quad. I picked out this lineup specifically for this amp to give the best balance of tone, reliability, and low noise. The adjustable Fixed Bias was set to %64 Class AB Plate Dissipation with a B+ of 444 VDC. All pots were cleaned and hardware tightened.