View Single Post
  #15  
Old 05-07-2017, 05:24 AM
Postman Postman is offline
Member
 
Join Date: Dec 1999
Location: where land meets sky
Posts: 2,375
Default Re: Noisy talkback on the M40?

Quote:
Originally Posted by stefanboman View Post
About the talkback. Cut pin 1 and it reduces noise a bit.
But it's still a lot noisier than going straight to Xmon.
I do not have xmon but this is what works for me. I wired talkback to make it unbalanced through the master module using only pins 2 and 3. My talkback pre has no transformer and does not use phantom power, so at the master module I connected talkback pre's shield and cold signal together to MTM pin 3, and talkback hot signal to MTM pin 2. Similar change in the microphone's gooseneck. This makes the talkback signal unbalanced but totally isolated from the MTM's case and pin 1. In my case, the microphone internally connects its body to pin 1, the MTM's shield, but the pre's unbalanced input is connected only to microphone pins 2 and 3. Maybe I am very lucky, this totally isolated talkback shield from MTM shield and talkback is quiet.

edit: I did have some added noise through the MTM when I simply cut pin 1 between MTM and pre input, keeping a balanced signal. That would always be the first thing to try but I had better results doing what I described. I suspect my talkback pre has poor common mode noise rejection. It is a custom kludge from many years ago adapted to each new situation.
__________________
system specs in profile

Last edited by Postman; 05-07-2017 at 07:02 AM.
Reply With Quote