hum problem on ADR COMPEX FX760X-RS SOLVED

[pw8888]

Hi Guys
i hope i am posting in the right part of the forum.
Just bough one of those amazing unit . vintage. with output transformer

"but" ... i am getting 50hz hum on both output // louder on channel one .
could that be an easy fix ? condenser in the power supply going bad ?
just want to say that has NOTHING to do with the compressor noise floor. It is really something that ADD to the signal.just wondering that could be the transformer ? or wiring. another info is that the machine is NOT grounded at the moment.
i really appreciate your help !!
thanks
P

 

[radardoug]

If its not grounded through the mains cable, and it has transformers, it will probably hum. Why is it not grounded? Do you have a death wish?

 

[pw8888]

sorry i mean no EARTH in the outlet .

only 2 places in my home have earth.
now some of those ADR where NOT balanced in /out (no transformer)
i can check to go out of the unit unbalanced  bypassing  the transfomrer and check ?

 

[radardoug]

If you want serious results with studio equipment, it all needs a mains earth, and all the earths connected together. That is the first thing I would look at. The power supply may need recapping, but make sure you have grounded everything properly first.

 

[pw8888]

SOLVED !!
after many try... i just bypassed the INPUT AND OUTPUT transformer ... and i dont have ANY problem left...
strange...thanks !!

P

 

[radardoug]

Did you ground the unit?

 

[pw8888]

Did you ground the unit?

I did ground it but that didn’t change nothing at all. Still had this 50hz hUm (around -50db). Without transformer the unit is COMPLETELY quiet . Strange

 

[noulou]

http://rane.com/note110.html

 

[pw8888]

http://rane.com/note110.html

Thanks !
Great info !