E06 - Marshall JTM45 Clone - Analyze, Repair, Bias, and Test

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This 1989 Marshall JTM45 Reissue/ Metro point-to-point upgrade came in with a broken input jack, and a broken tube socket. As usual, we had some unpleasant surprises after we fixed the obvious problems. We diagnosed a red-plating tube and show a few measurements that are helpful for setting output tube bias. After the repairs, this amp sounds fantastic for country/blues crunch or early creamy power chords.
00:00 - Opening and description
01:37 - Teardown and Inspection
03:04 - Tube socket repair
07:12 - Input jack repair
07:43 - What's a cathode-follower driven tone stack?
10:10 - What does a red-plating tube look and sound like?
11:08 - Tim calls!
12:44 - Verifying the output tube connections
16:06 - Checking output section "hot"
20:17 - Biasing (with some of my personal biases revealed!) - testing and verifying.
26:14 - Testing

Видео E06 - Marshall JTM45 Clone - Analyze, Repair, Bias, and Test канала Wally's Wattage Cottage