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

"but at this level of hi-fi I have certain expectations"

Then you you need to serious about the size of your room. I don't think you will get satisfaction inside a closet with any setup other than headphones.

So even from a distance, I can hear it in between songs.

If you hear it from your listening position, it’s got to get solved. P.S. I have never had a hum issue I could not solve. First step is isolating the problem. Isolate it, then I’ll give you some ideas.

Edit. If amp hums with just the speakers hooked to it, it's the amp. Tubes are always suspect. Is it in both channels? Did it always hum? You might need a call to Upscale.

 

You mentioned using an extension cord. Here is my question. Did you plug the cord into the same electrical circuit as the amp is already on? If there is trouble with that circuit, it may not matter what outlet you use IN THAT CIRCUIT. Make sure that the test circuit is on a different breaker. If that works, great. You get to hunt down a loose connection or who knows what.

@dill Agreed and thats the goal.  Looking to move next year but for now, the closet office is the only place I can set this up.  I have one of those....what do you call them again, oh yea, a wife, that doesn't want so much stuff in the living room.  Nor do I want it accessible to my 6 year old who loves to push buttons beyond their limits.  @4krowme  I used a plug pre remodel so I assume its on a different circuit.

Well crap, Now I Have a Hum.... but I can fix it. Building a new amp this week.