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I have deoxit’d all the pots already but I was thinking the same thing regarding a possible tone circuit issue. You are right about the record output bypassing the tone pots and it also bypasses the pre-amp amplifier circuit (volume and balance pots). I looked at the schematics and I can jumper the tone section out completely, pull the JFETs on the muting circuit and then the amplifier circuit will be isolated. That should at least pin-point which circuit that is have trouble. Thank you all for the input; it has really helped me a lot.
DH-100 Update: I isolated the amplifier and still had the problem. I re-inspected the amplifier circuit and discovered I put .047 mf caps in the op-amp circuit that should have been 47 pf caps ( I think that's 100x less f). They were the only caps that didn't come in the re-cap kit I bought (my bad; oops). All it took was a quick trip to the electronics shop and a couple of minutes with the soldering iron, if you don't count the 1,000,000 hours I spent troubleshooting and test listening. I just finished testing it and it sounds awesome: is "stage" when you hear different instruments in different spots? if it is that it's got great staging. The bass is a bit understated and the highs can be too forward with pop/rock, but nothing that gentle twists of the tone control knobs won't hide. I'm so relieved to get this right; it was close to becoming an anchor. I could have never limped through this without the input I got here on Audiogon. Thanks!