2. amps-preamps
  3. 157716-124365

Help with Hum issues.

I need to pick your brains please:

As I am going crazy with this issue:

Everything listed is Solid State.....NO tubes.


Ok, so when I had my Onkyo Amp and pre amp connected, I had a hum in the Right Chanel. This is the same Onkyo Amp where I ended up burning the transistor and fuse because I was trying to eliminate this Hum issue.

It sounds like Vooohhhh. and it is constant.


I thought it was the Amplifier.


Now I have a Mitsubishi amp connected to a phase linear pre-amp and a separate tuner. The Left Chanel is clean and has no hum noise, when I switch the speaker wire (same speaker & wire) to the Right side I get that same hum again I was getting in the other setup.


This same hum was happening when I lived in a different city.


I don't understand what or why this is happening. I replaced components, wires, speakers, outlets where the components are plugged.  I plugged everything into one power strip, different strips, into the back of the pre-amp and made no difference.


Why do I keep getting this hum in the R side Only ?


It is driving me nuts and don't know how to get rid of it. I grounded the system every which way, it made no difference.


Would appreciate any help.


Thank you,
customersfirst
customersfirst OP
12 posts
 
It is NOT the tuner.  If you read my post, different sources have been tried.  The hum is always there.
newbee
4,767 posts
 
OK. Did you try what I suggested?  What happened?  That always works for me when I'm trying to source a problem.
customersfirst OP
12 posts
 
Ok, I did that again and here is what happened:

Disconnected everything.

Plugged the Amp in with speaker attached.  No hum.

Plugged pre amp and attached it to Amp.  When I turned on the pre-amp the hum is back.

All is plugged into the same power strip.

My understanding is that I would not get a hum anyway by just plugging in the Amp since it needs a pre-amp to do anything.

So I doubt it is the pr-amp that is causing the hum.

Again...I was using a different pre-amp and amp before and I was still getting the SAME hum in the Right side....no matter what speaker or wire I used.
Post removed 
newbee
4,767 posts
 
Have you tried using a ’cheater’ plug on the end of the preamp power cord? Some times it is good to have only one plug with the ground (on the amp cord) - the rest of the stuff benefits from that ground. It is safe, if not preferable, to use the cheater plug on the pre-amp (if that works) until you can source the ground issue causing (if it is) your hum.

Although I don’t think your problem is the power strip, to rule out one more possibility, you might plug them into separate outlets and see what happens. Another thing to consider is the placement of power cords and IC’s. If you can, be sure that they are not close to each other and if they must cross do so as close to crossing at a right angle.

And if you have used the same IC’s with all of your stuff make sure you have IC’s which are properly constructed to reject EMI. I had a right channel hum once that was the result of one IC passing too close to a transformer. (I recently saw a diagram of a Canary IC, LV-77s on Blue Jeans site which shows a high quality insulation/reject of EMI which is used in their own audio cables)

FWIW, there is no easy fix for your problem, I think. Since you have used different amps and preamps with identical results its got to be some where in the electronics preceding the preamp.  

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