Sound Skulptor forums
Build help and troubleshooting => MP573 Microphone preamplifier => Topic started by: musicarr on July 07, 2025, 03:10:31 AM
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Hi,
I've finished doing the build, and have started testing. Step #1 is to do a short circuit test. As I am very new to this, I'm uncertain as to how to specifically go about getting the correct readings. Here's what I've done so far and the readings I've gotten.
Multimeter set at 200k ohms
Black test lead is on common input
Red test lead is on ohms input
Check #1
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V- has black test lead
OV has red test lead
Result: 80.xx - continues to slowly increment
Check #2
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V+ has red test lead
OV has black lead
Result: 75.xx - continues to slowly increment
Any other combination of leads on V-, OV, and V+, gives me a reading of ‘OL’ which according to my multimeter, is ‘over limit’, but that’s also what it says when the leads aren’t touching anything.
What I don’t know is if these readings are what they should be. I’m very knew to this, so any input is helpful, as I continue to learn.
One thing I was also a little confused about the JMP3. Should it have the jumper in place or not when doing the Short Circuit test? The build guide directs say to put it on, so by the time you get to the setup guide, I'm assuming it's supposed to still be on, as I didn't see anywhere saying to take it off. But -- in step #2 of the setup guid, it says to the put the jumper on, which is odd, as it's already on. Did I miss something saying to take it off before doing test #1, or should is still be on?
Thanks
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Any other combination of leads on V-, OV, and V+, gives me a reading of ‘OL’
This show you are OK. The resistance is too high to be measured.
Should it have the jumper in place or not when doing the Short Circuit test?
It doesn't matter.
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Great, sounds like I'm ready to continue testing.
As to the readings I WAS getting - is that what I should see? What do they tell me? Just trying to understand everything.
Thanks
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0L on the DMM means resistor is too high to be measured. In this test check there is no short circuit or very low resistance.
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Got it. Thanks.