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Old 19th July 2012, 10:45 PM   #11
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Quote:
Originally Posted by Osvaldo de Banfield View Post
Ok, the other channels work fine, OK, but may be a fake cap in the circuit (For example, the power decoupling, the cap in zobel network, or some RC compensation network) that makes THIS amplifier to oscillate / become unstable, and don't affect the other(s).
Good point but all the caps are genuine. I bought all the parts myself off Mouser.

I might take a look at some of my soldering on the preamp section. Generally my soldering is good, but I remember having a sketchily soldered cap or two because they didn't quite fit right.
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Old 20th July 2012, 12:58 PM   #12
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swap channels.
connect the "good" side pre-amp to the "bad" side power amp.
if the pre-amp is the stinky part, you will notice it.
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Old 20th July 2012, 01:13 PM   #13
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Here in Argentina (Buenos Aires) there was a time some years ago where some electrolytic caps exploded in the caps drawer, without use.. They were a 105 deg low ESR for motherboards or SMPSīs. The brand Jackon or something like this. Actually we are using Nichicon although costs are higher.

This is to remark that donīt be sure caps are good, measure them although appear to be good.
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Old 20th July 2012, 04:04 PM   #14
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Originally Posted by Osvaldo de Banfield View Post
Here in Argentina (Buenos Aires) there was a time some years ago where some electrolytic caps exploded in the caps drawer, without use.. They were a 105 deg low ESR for motherboards or SMPSīs. The brand Jackon or something like this. Actually we are using Nichicon although costs are higher.

This is to remark that donīt be sure caps are good, measure them although appear to be good.
I'm quite aware of bad caps. But I used 100% Panasonics on this amp. I'll look around to see if anything looks suspicious though.
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Old 20th July 2012, 04:06 PM   #15
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Originally Posted by Arty View Post
swap channels.
connect the "good" side pre-amp to the "bad" side power amp.
if the pre-amp is the stinky part, you will notice it.
They're all on a single board, so I can't swap. However, I think I'm just going to use the brute force tactic. Just replace everything that I have a problem with and hope the sound goes away. Maybe I'll get new op-amps too. My op-amps were actually a little weird. I had to replace one actually because it seemed to be a dud. Maybe the other one went bad now.
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Old 23rd July 2012, 06:13 PM   #16
johnr66 is offline johnr66  United States
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This is where an oscilloscope would come in handy. It could be oscillation with a signal present, such as "bottom side fuzzies" and such. Did this kit come from China?
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Old 27th July 2012, 12:49 PM   #17
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Nice wooden box but it may be problematic.

Gajanan Phadte
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