Marshall PA20 (1917) Circuit Analysis, Patching, Modification and Sound Tests. Part2 @nickadams5411
Marshall PA20 (1917) Circuit Analysis, Patching, Modification and Sound Tests. Part2 @nickadams5411
Uploaded January 2017 | Updated September 2026, 1 week ago
Marshall PA20 (1917) Tube (Valve) amplifier head. Built 1971
NOTE: There is a full circuit analysis, but there are sound tests (with a guitar) towards the end.
Measurements and circuit tests.
Explanation of "Input Patching"
A Simple "High Gain" modification.
Note: This is Part 2 (of 3) comparing the WEM ER15 PA head and this Marshall PA20 head.
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Marshall PA20 (1917) Circuit Analysis, Patching, Modification and Sound Tests. Part2

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