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RE: PAS-3 right channel hum

Posted by petercapo on January 18, 2017 at 19:45:47:
If your tech is going to be diving into it, he might want to think about eliminating what appear to be a number of ground wires that might not be necessary. It might not be possible to implement Bill Thomas' fix the way he did if you have more ground wires than he did. This is another reason why I wanted to offer you a simpler approach with moving just the one wire (and also removing the wire from eyelet 8). Of course, my idea might not help depending on all the other stuff going on in your preamp.
I suggest you get your tech a copy of an original Dynaco PAS manual along with its corresponding pictorial diagrams. With regard to ground wiring, I suggest a later PAS manual, such as for the PAS-3X, though it may not be appropriate for certain other aspects of troubleshooting, especially since your PAS is not in any standard Dynaco configuration.
With regard to changing to a different PC board... keep in mind that with the nonstandard and possibly redundant grounding scheme you have now (that could be causing ground loops), your existing line board isn't really getting a fair chance. That's not the original line board, anyway. It is a newer, fiberglass board, so it has already been changed-out. It's the ground wiring that is causing your hum problems. Switching to a different circuit board design may or may not help the hum, depending on how it integrates into your existing grounding system of wires.
I offered the suggestions that I have in the hope that it might alleviate the hum imbalance. But, what your PAS really needs is a complete reworking of the grounding by someone who is very familiar with both the original PAS and the grounding needs you now have with the tubenirvana cap board. If it were my PAS, I'd just remove every ground wire there is and start from scratch.