mic randomly goes quiet

Patrick Horgan

New member
Jul 22, 2019
2
0
1
64
US
This may seem obvious to more experienced folk, but I'm tearing my hair out. I run sound for a Buddhist sangha, and we have been having problems with the mic cutting out, and just by unplugging and replugging the mic, the sound comes back.
We rent space in a Unitarian church, and they have a panel on the wall with a couple of xlr connections to go to their amp.

Their amp does not provide phantom power and the usual presenter's favorite Countryman earhook requires it, so we have a small Rolls three mic mixer just to provide the phantom power (it provides 12 VDC) and then to plug into the house system. It worked fine for more than a year, but then started randomly shutting off.

While trying to diagnose this problem we:
o replaced the cable on the countryman
o substituted a Rode lav for the countryman
o substituted another Rolls mic mixer
o substituted a ProFX 8 v2 which supplies 45 VDC phantom power

Eventually we had substituted everything except for the house system, but I can't think of a way that the house amp could fail in a way that unplugging and replugging the mic would instantly and reliably fix it.
 

Art Welter

Senior
Jan 11, 2011
815
13
18
Florida
Patrick,

Sounds like you have ruled out your end of the system as being at fault.
Unplugging and plugging in a phantom powered mic often creates a high level transient with enough amplitude to "break through" a dirty/tarnished connection.
It is possible that the connections between the wall panel and the xlr connections to their amp/mixer have become oxidized enough to not pass lower level signal, unplugging and plugging those back in several times might reduce the tarnish enough to work consistently- cleaning those connections with a cleaner like DeOxit may fix the problem.
If that is not the problem, their mixer itself may have internal connection problems requiring either cleaning or re-soldering connections.

Art
 

Patrick Horgan

New member
Jul 22, 2019
2
0
1
64
US
Patrick,

Sounds like you have ruled out your end of the system as being at fault.
Unplugging and plugging in a phantom powered mic often creates a high level transient with enough amplitude to "break through" a dirty/tarnished connection.
It is possible that the connections between the wall panel and the xlr connections to their amp/mixer have become oxidized enough to not pass lower level signal, unplugging and plugging those back in several times might reduce the tarnish enough to work consistently- cleaning those connections with a cleaner like DeOxit may fix the problem.
If that is not the problem, their mixer itself may have internal connection problems requiring either cleaning or re-soldering connections.

Art
I hadn't thought of a transient punching through a resistive connection. Hmmmmmm. Nonetheless the house isn't interested in doing anything so we're using a powered speaker/amp and everything seems fine -- except we don't have the house's assistive listening devices. Looking into getting our own. Thanks for your help. Wish I had more control/access:(