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

PRESS "SHOW MORE" for a link table! 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