Hi Mark -- As of this evening, I have found transistor covers for the 8-fin heat sink that I am transplanting onto my PL400. I will therefore should have the two transistor covers from the now-defunct 4-fin heat sink available for you. Once I get everything in hand and triple-check it, I can send you the two covers. Please send me a PM and let me know your mailing address.
-Jon
-Jon
"Spraying the Innards" won't do anything. When resto'ing one, you do what you think needs doing. Wires? Maybe, new transformer? Sometimes, new meters??? Sure...... New Switches and fuse holders?? Yesssss.......... It's like restoring an old car, you rebuild, repair, clean, replace whatever needs the attention. If all else fails, spray bomb it and and tell everybody you restored it but lost the receipts. 
I like meters on a Variac (not really on an amp). When using one with meters, you can tell when issues are occurring without having to hook up a bunch of test stuff. But, you got to know your equipment and recognize how they act when working correctly (Current/Wattage draws) and by paying close attention you know if you need to pull out the test equipment. I only use the DBT on fresh amps. I think Staco made a couple metered models and I wait to find what I WANT, not what I pay for it. It's better to be satisfied than wishing you would have scored my dream machine.
- Joined
- Jul 12, 2022
- Messages
- 2
I know I’m late on this. I have fully rebuilt 2 PL400s using the White Oak kits. In general these are fantastic in terms of stability and sound quality. I went full comp on both. The backplanes take a hot iron and patience to build, but are not really that difficult. The phoenix connectors are convenient and non-ferrous, so they won’t seriously affect the sound. I would pay extra attention to the wiring in the signal path, and maybe bypass the phoenix connectors for those. I built both my amps with the Watts Abundant relay boards. This gave me lots of confidence that I wasn’t going to launch my speaker cones. However, any kind of fusing or surge protection is going to affect your sound. On one amp I removed the relay board and added output tube connectors (ala GR Research). The result was a remarkable improvement in sound stage, clarity, and imaging. The WO boards are quite stable, so In my opinion the risks are minimal. So — if you are risk-averse go with the protection circuit. If you want to get the most out of your amp skip the relay and replace the binding posts with tube connectors.
