2. misc-audio
  3. 174831-87123

This 60 Hz hum is driving me crazy

I just got a new to me, Prima Luna Prologue Premium Integrated tube amp. Sounds great, but there is a "ear to the speaker" 60 Hz hum. Hum sounds the same if I adjust volume +-/  The only thing I have connected is a Parasound Zdac.  Speakers are Rega RS1 Here is what I have tried:

1. I disconnected the Zdac so it was just the PL connected to the speakers with no other inputs. Hum still there.

2. While Zdac still disconnected, I use a 3-to-2 prong adpater to determine if its a ground loop.  Still there.

3. The outlet is a new one added from our remodel.  So I used an extension cord and plugged into an original outlet to see if the electricity was "dirty."  Hum was still there. 

Now here some possible culprits.  

* The stereo is perhaps set up in the smallest man cave in California.  The speakers are about 2 feet away from preamp.  I will try moving speakers further. 

* I am using crappy Amazon 12 AWG cables.  I have some better ones coming from Morrow Cables. 

* The stereo is in front of the panel that our internet wiring comes in through (I am in a condo complex).  There is no wireless there, but perhaps I should set up system somewhere else to try.

* I am using the tubes from the previous owner...do I just buy a set of new tubes?  

Is there anything else I should try?  Thanks in advance.

 

comedyzen
dill
2,517 posts
 

For tubes I suggest Jim McShane or Brent Jessee. Both have websites and are good sources for tubes. Jim for good prices, Brent for the best.

You might have a ground issue inside the amp. I had one in my phono stage that was fixed by removing some paint from under the chassis ground wire. There was not enough bare metal exposed to make a good ground. The paint was acting like an insulator.

comedyzen OP
15 posts
 

Thanks @dill! I will google their names.  There is no phono stage on mine but there is a ground mount on the back for a phone preamp.  To your point:

Talking to someone from Upscale service.  I mentioned that I lifted the ground but he still thinks its a ground loop.  He basically told me to Google it and try other things.  Haha

 

dill
2,517 posts
 

My phono stage is a separate, stand alone unit plugged into an integrated amp via interconnects and is about 1 1/2'away from the amp. The ground wire inside was insulated by the paint. I took off the ground wire, scraped the paint off and bingo, no more hum.

Post removed 
dill
2,517 posts
 

That is a good idea steakster!

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