malabarmusic
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- 1,702
My '72 Hiwatt DR-103 has got a hum issue that is proving hard to trace.
It's not too bad, except when all three volumes are cranked or close to it. At that point, moving the Bass knob past 11:00 brings up a low-level 60-cycle hum that gets progressively louder as the control is turned up. At max bass (not that I'd ever play it there), the hum is so annoyingly loud that it makes me wonder if something could be faulty.
The amp has been gone over by a very good tech. The tubes are new and test fine. The bias is set just a tad on the cold side of "normal." All ground wires have been thoroughly traced and no loops found. All filter caps were just replaced with the proper values.
Should I to learn to live with this hum or should I press on in quest of a "fix"?
- DB
It's not too bad, except when all three volumes are cranked or close to it. At that point, moving the Bass knob past 11:00 brings up a low-level 60-cycle hum that gets progressively louder as the control is turned up. At max bass (not that I'd ever play it there), the hum is so annoyingly loud that it makes me wonder if something could be faulty.
The amp has been gone over by a very good tech. The tubes are new and test fine. The bias is set just a tad on the cold side of "normal." All ground wires have been thoroughly traced and no loops found. All filter caps were just replaced with the proper values.
Should I to learn to live with this hum or should I press on in quest of a "fix"?
- DB