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Post by nicholasb on Nov 30, 2021 4:00:49 GMT
Mmm. Checking bias across the emitter resistors, bias was almost non-existent in one amp and quite low in the other. Tweaked bias up in both to the mid twenties mV. Temp diff between the two amps has gone down to just 1.5C now. Might leave the amps alone now, while they're still working .
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Post by nicholasb on Dec 2, 2021 4:14:23 GMT
My MESR-100 ESR meter arrived today.
The old Jamicon 6800uF e-caps came in at:
1. 0.018 Ohms 2. 0.018 Ohms 3. 0.015 Ohms, and 4. 0.015 Ohms
Still pretty good. The spare new CDE I have reads 0.011 Ohms (the other four CDEs were put into the amps before I could measure them). So swapping the e-caps was just for practice. Still, the amp may have benefitted from the change-over of some of the smaller e-caps.
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solderdude
Administrator
measureutternutter
Posts: 4,881
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Post by solderdude on Dec 2, 2021 22:03:57 GMT
I think it benefitted most of the bias adjustment. The lack of idle current in one side may well have been audible.
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Post by nicholasb on Dec 16, 2021 6:28:48 GMT
I think it benefitted most of the bias adjustment. The lack of idle current in one side may well have been audible. Indeed, that would almost certainly be the case, I would think. They do sound better to me - but that could be my expectations. As indicated earlier, changing the e-caps was more an exercise in preventative maintenance. Today, my replacement X2 capacitors finally arrived. About six years ago, one of them had self-destructed (smoke) open circuit - as it should. I soldered in the new one and replaced the old one on the other amp as well. No more fiddling around with the amps for a while! For anyone else reading this, the X2 capacitors are safety capacitors, that go between the live and neutral lines where they come into the amplifier (on the inside though), designed primarily to take garbage off the powerlines, etc., I believe.
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