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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: bcrowell on June 05, 2022, 05:15:03 PM

Title: Damaged inline Shure preamps?
Post by: bcrowell on June 05, 2022, 05:15:03 PM
I'm an amateur audio engineer helping out a nearby school, and I have a puzzle I'm hoping an expert can help me solve.

They had three Shure MX202 wired hanging mics above their stage, but two of them were outputting a very noisy and pretty much useless signal. I've got my hands on the two bad ones and plugged them into digital recorders with phantom power. The mics themselves seem fine, but it seems the inline preamps are busted somehow. They both make a loud fuzzy noise like a needle on a dirty record, and one of them "pops" occasionally, with or without the mics plugged in. I expect I'll need to send them to Shure for repairs, but what I really want to know is what's wrong with them, whether they're damaged somehow, and how it happened to two out of three preamps zip-tied to the ceiling. I want to make sure whatever happened doesn't happen again.

Thoughts so far:


Any suggestions on what to do or how to test?
Title: Re: Damaged inline Shure preamps?
Post by: Scott Holtzman on June 05, 2022, 08:33:04 PM
I'm an amateur audio engineer helping out a nearby school, and I have a puzzle I'm hoping an expert can help me solve.

They had three Shure MX202 wired hanging mics above their stage, but two of them were outputting a very noisy and pretty much useless signal. I've got my hands on the two bad ones and plugged them into digital recorders with phantom power. The mics themselves seem fine, but it seems the inline preamps are busted somehow. They both make a loud fuzzy noise like a needle on a dirty record, and one of them "pops" occasionally, with or without the mics plugged in. I expect I'll need to send them to Shure for repairs, but what I really want to know is what's wrong with them, whether they're damaged somehow, and how it happened to two out of three preamps zip-tied to the ceiling. I want to make sure whatever happened doesn't happen again.

Thoughts so far:

  • Cabling doesn't seem to be an issue, as the preamps don't have cables and the preamps themselves seem pristine
  • Maybe some kind of power surge left everything else intact but busted these two preamps
  • Maybe shoddy capacitors inside the preamps died, might open the preamp to see if there's visible damage
  • Maybe I'm not doing a good job testing, going to get my hands on the working one from the school to test against
Any suggestions on what to do or how to test?


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