2. amps-preamps
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How to check my preamp for a DC leak

Hello,

After posting in a previous thread about my amp cutting out every now and then, it was suggested to me that mu preamp may have a DC leak.

I bought myself a multimeter, but I'm not sure how to check for a DC leak. Would anyone be able to tell me where the leads should be connected, and whether I need signal coming into the pre to test for this?
rrolack
rrolack OP
54 posts
 
Thanks for the explanation. If this cutting out is only happening intermittently (e.g. every few hours or so), should I be able to measure elevated DC levels at all times, or only when the unit is causing a problem in my system?
rrolack OP
54 posts
 
Any thoughts on my last question? If anyone knows the answer to this, it would be much appreciated!
mlsstl
694 posts
 
Intermittent problems are among the hardest to run down. It could be an issue of a bad capacitor that only misbehaves when it charges to a certain point. Or it could be temperature related or tied to the type of signal. Cold solder joints are also suspect in this type of situation.

I'd measure for DC under all conditions - when it sounds OK and when it is misbehaving. There's a more than fair chance this is going to take some bench testing by a a good electronics tech.
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