Revive Your Marshall JMP-50 (2204) With Repairs And Upgrades!

The JMP50 is my favourite Marshall amp, both the 4-hole (4 input sockets) and 2-hole versions. I hope you enjoy this journey of repair and improvements to this classic. You will learn about a “Cold Clipper Stage” and how Marshall (and others) create a flexible, but potentially flawed, cascading gain stage. Or skip straight to the 43:00 to hear how this historically important amp sounds.
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Video Index
00:00 Introduction
04:00 What is a “Cold Clipper” Stage
06:05 How Marshall incorporates a “Cascading Gain” stage in the 2204 circuit
17:30 Overview for improving Ground connections
21:42 Two “Star Ground” points
29:39 My tool for cleaning Cliff-style jacks
31:50 Attempts to save the original Marshall knobs
34:03 The importance of Matched Tubes for accurate bias of the power tubes
43:00 Sound sample of the completed Marshall JMP-50