[lmf22]

I have a ground loop hum/buzz problem with my PS Audio GCPH phono preamp, and wondering what I can do to solve it.  I've isolated the problem to the GCPH by doing the following experiment:
 
1. Unplugged everything from my integrated amp, except the headphone amp which is connected to its Tape Out.  (No buzzing)
2. Plugged in the Rega DAC into integrated amp. (No buzzing)
3. Plugged in radio tuner into integrated amp. (No buzzing)
4. Plugged in phono preamp into integrated amp. (Buzzing starts)
5. Plugged in turntable into phono preamp.  (No changes from step 4; buzzing)
6. Used a cheater-plug (3-prong to 2-prong adapter) on the phono preamp. (No buzzing).  This solves the problem but I am afraid that using a cheater plug might be unsafe.  Also, having a $1 cheater plug on a $50 power cable doesn't make much sense. 
 
There's buzzing even when the GCPH is not on; simply connecting the signal cables and power cable will produce the buzzing.  The buzzing gets louder as the volume control of my amps. 
 
All my audio components are connected to the Elite 15 PFi power conditioner (also tried the APC S15) and there are no other things connected to the outlet where power conditioner is connected to.  All of my components have 3-prong electrical plugs except the turntable, headphone amp, and radio tuner.
 
I've also tried connecting the ground nut in the back of the GCPH to the ground nut on the back of the APC S15.  Funny thing is when I do that there's a buzzing even when the power cable is NOT connected. 
 
Any help would be much appreciated. 

 

[Stevtt]

Not much to tell you except mine is dead quiet. How far from the amp is it?

 

[lmf22]

Quote:

Not much to tell you except mine is dead quiet. How far from the amp is it?

Initially, it was on the rack right below the integrated amp.  But today I've moved it about 0.5 ft lower and about 1 ft to the left of the amp.  Still buzzing. 
How far should a phono preamp be from the amp?
 

 

[dallan]

I have a ground loop that i discovered on my PSaudio digital link dac.  It mentions the problem in the owners manual too.  Didn't have it until i plugged in my iems then checked on one of my more sensitive pairs and there it is.  I can kind of lessen it by moving the amp around a bit but can't get rid of it.  Doesn't effect my higher impedance phones.

 

[lmf22]

Quote:

I have a ground loop that i discovered on my PSaudio digital link dac.  It mentions the problem in the owners manual too.  Didn't have it until i plugged in my iems then checked on one of my more sensitive pairs and there it is.  I can kind of lessen it by moving the amp around a bit but can't get rid of it.  Doesn't effect my higher impedance phones.

You're right, it doesn't affect high-impedance headphones.  With my T1 I would have to turn the headphone amp up to full volume before I notice it.  With the B&W P5, I can hear buzzing at half-way (12 o-clock) position on the volume control.  (I never listen that at volume!)  On the integrated amp, I can hear buzzing from the speakers when the volume is at 60-70 (80 is the max volume). 
 
Different when listening to vinyls though.  When I switch to the input that the GCPH is connected to, the buzzing can be heard at lower volume settings.  It's hard to get that perfect gain on the GCPH and volume control on the headphone amp to minimize the buzzing. 
 
It also bugs me knowing that the buzzing is there.  A $1000 phono preamp shouldn't have this problem, right?

 

[Stevtt]

I've got mine sepirated by a shelf. I will plug In my es5's tonight and let you know if I get anything

 

[Stevtt]

Just tried it. Ran it balanced through an SR-71b to my ES5's and nothing. No buzzing or hum at all. Also quiet running RCA's out to tthe amp pwering my speakers and nothing.

 

[dallan]

Mine is on a separate shelf.  It happens when my amp volume is against the bottom stop or when turned all the way up, which you would never listen to it at.  I also hear it late at night if i plug in the headphones when the house is quiet and i am using closed in the silence at any volume, but when the music starts it is below anything.

 

[lmf22]

Thanks everyone for testing.  Maybe I'll just learn to live with it.  It's not bothering me unless the amp is turned to high volumes, which like dallan said, I never listen at such high volumes.