While listening the other nite the right channel gets ragged around the edges and distorts on transient peaks. Quick check reveals dc offset and bias are both way overboard and far beyond anything I've experienced due to 6AS7 failures in the past. After shut down, visual inspection of 6AS7s reveals no triode failures. Visual inspection of 6SN7s not possible and no tube tester is handy so a swap of all driver tubes to other M-60 is performed, the amp powered up and dc offset/bias checked and, voila, both are wildly off. In go new drivers and, after appropriate warm-up, dc offset and bias are fine tuned uneventfully. So far so good. Next day I borrow a Hickok 532 to test suspect 6SN7s. All test out beautifully, not gassy, nothing. Now I'm stumped. Anybody got an idea? Incidentally, I did take the time to test all the 6AS7s with no failures to report.
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Topic - M-60 dc offset/ bias run amok - acres verde 13:57:43 11/16/04 (12)
- Re: M-60 dc offset/ bias run amok - Legendre 09:35:34 11/17/04 (0)
- Re: M-60 dc offset/ bias run amok - cousinbillyl 21:26:33 11/16/04 (10)
- Re: M-60 dc offset/ bias run amok - bryan 07:15:03 11/17/04 (9)
- Re: Bryan, thank you - cousinbillyl 12:03:28 11/17/04 (8)
- Re: Bryan, thank you - bryan 09:20:02 11/18/04 (7)
- 12SX7s - Lew 11:08:26 11/18/04 (2)
- Re: 12SX7s - bryan 14:42:30 11/18/04 (1)
- Re: 12SX7s - Lew 07:11:11 11/19/04 (0)
- Re: Bryan, thank you. Source for 12SX7's - cousinbillyl 09:29:29 11/18/04 (3)
- Re: Bryan, thank you. Source for 12SX7's - bryan 09:39:39 11/18/04 (2)
- Re:Source for 12SX7's, - cousinbillyl 14:08:05 11/18/04 (1)
- On Sale at AES for $23 (nt) - LineArrayNut 22:17:36 12/13/04 (0)