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MP573 Microphone preamplifier / Re: Bias Adjust

« on: July 01, 2024, 09:11:49 PM »

Thanks.  Should I wait for the voltage to settle before I adjust P2 to 3 volts or will it be ok the way I adjusted it right after I powered the unit on?

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MP573 Microphone preamplifier / Bias Adjust

« on: July 01, 2024, 12:57:10 AM »

I have a question about the bias adjust portion of the testing.

I place the positive (+) test probe from the DMM on TP4 and the negative (-) test probe from the DMM on TP2.  I power on the unit and adjust P2 until I read 3 volts.  My question is after I get P2 adjusted to 3 volts the voltage begins to drop very slowly and continues to drop over time.  Is this ok?  If not what do I need to do to fix it?

I appreciate any input.

Thanks,

Evan