Focusrite RED 3 acting very strange

[studiotech]

I got a strange one tonight. We have a RED 3 stereo compressor that is a little noisy with only a single channel engaged, but with both channels engaged, the noise floor goes way up and a rather loud buzzing sound is heard.

As measured at the outputs with no input signal:

either channel bypassed, we have a reference noise floor of -76dBu
either channel "IN" and the noise floor rises to -52dBu
Both channels "IN" and it jumps up to -31dBu accompanied by a buzzing sound...not a hum or a hiss, but a definite buzz that's totally not present with only a single channel engaged.

I have a recording of the sound if anyone wants me to upload that.

Thanks so much for any hints.

Greg

 

[pucho812]

I had a similar issue on another unit, not a red 3 or even focusrite but I know I should have measured a noise floor way lower then what I was getting and had buzz. Turned out to be the filter caps.

 

[mjrippe]

Yup, sounds like PSU recap time.

 

[fazer]

Yup, replace the audio caps also. If the filter caps are bad, the 100 uf coupling caps will need it also. WilL sound amazing afterwards

 

[studiotech]

Thanks, everyone.

 

[CJ]

what kind of switches does it use? mechanical or solid state?
if mechanical, try some deoxit, if solid state, you might have a fet problem if it uses fets.

hum would be power supply, buzz sounds like something else,

measure the freq of the noise, 60 hz is ground problem, 120 hz is pwr supply