Test Conditions:
a) No external connections other than power and a cabinet.
b) muted input
c) all controls at noon
Expected Result:
The amp should not produce any noticeably objectionable hum or buzz..even at max output. Some slight white noise proportional to gain/volume/volume is to be expected, but this is slight and largely un-noticeable at most normal volumes.
Problem Result:
From my earlier post as to hum and its susceptibilities. "the level of hum reduces as you increase gain, dramatically increases as you increase volume and is proportionally variable with changes in the master volume."
Recommended Fix Procedure:
1. Completely disconnect the amp from everything.
2. Remove the 12 screws holding the top cover using a 2mm allen wrench.
3. Tighten those pcb mounting screws that have a washer..these are grounding points...do not overtighten as you may strip the supporting pillars.
4. Refit the top cover, taking care not to overtighten the screws as you can strip the side panels.
IMPORTANT NOTES
1. Its your amp, proceed at your own risk.
2. If you dont know what you are doing, or are prone to ham-fistedness, dont do this (see Note 1. above).
3. Needless to say, opening the amp will theoretically void your warranty (see Note 1. above).
4. This is not a guaranteed fix, there are obviously several failure mechanisms that can cause hum/buzz in the output including but not limited to noisy components, really bad mains, ground loops, mice and extra terrestials. (ie its worth trying, but see note 1 above).
5. If you forget to unplug the amp despite step 1 of the repair procedure and electrocute yourself, blame Darwin, not me. (didn't i say see Note 1?)
6. If anything else gets broken, lost stops working or damaged, re-read Note 1.
Yup, I think that covers it
a) No external connections other than power and a cabinet.
b) muted input
c) all controls at noon
Expected Result:
The amp should not produce any noticeably objectionable hum or buzz..even at max output. Some slight white noise proportional to gain/volume/volume is to be expected, but this is slight and largely un-noticeable at most normal volumes.
Problem Result:
From my earlier post as to hum and its susceptibilities. "the level of hum reduces as you increase gain, dramatically increases as you increase volume and is proportionally variable with changes in the master volume."
Recommended Fix Procedure:
1. Completely disconnect the amp from everything.
2. Remove the 12 screws holding the top cover using a 2mm allen wrench.
3. Tighten those pcb mounting screws that have a washer..these are grounding points...do not overtighten as you may strip the supporting pillars.
4. Refit the top cover, taking care not to overtighten the screws as you can strip the side panels.
IMPORTANT NOTES
1. Its your amp, proceed at your own risk.
2. If you dont know what you are doing, or are prone to ham-fistedness, dont do this (see Note 1. above).
3. Needless to say, opening the amp will theoretically void your warranty (see Note 1. above).
4. This is not a guaranteed fix, there are obviously several failure mechanisms that can cause hum/buzz in the output including but not limited to noisy components, really bad mains, ground loops, mice and extra terrestials. (ie its worth trying, but see note 1 above).
5. If you forget to unplug the amp despite step 1 of the repair procedure and electrocute yourself, blame Darwin, not me. (didn't i say see Note 1?)
6. If anything else gets broken, lost stops working or damaged, re-read Note 1.
Yup, I think that covers it
. I've been all over the Tone Primer thread and i think i'm ready... hahaha! 
