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

UGH!!  Fresh set to tubes from McShane...perhaps a slight decrease in buzz, but it's still there.

Looking for Bay Area recommendations for stereo repair.  I don't know what else I can do.

FYI, Upscale Audio was completely useless and the customer service was quite half ass.  I do appreciate that they got back to me, but their replies were very "figure it out or Google it."  Which I did.

Hums, buzzes and all that. Been there done that. Ditched tubes, went all SS and never looked back. Liked the tube “sonics” but “noise” bugs the Shitake out of me. The issue is most likely your household. It literally could be a bad plug or light switch somewhere on the circuit. Another thing to look at is any LED bulbs on the circuit or dimmers. Notorious. 
 

 

 

Ooooh.  I have LEDs and dimmers.  But I took the unit to my condo complex's main lobby and plugged in there.  Got the buzz.but there are LEDs galore.  Maybe I need to take it to my office that was built in the 60s

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.

Shorting the RCA shell and center conductor would be the best. If it is floated it “could” be more noisy, but it should also be something like 100k ohms.

Whatever a Zdac is, then leave it connected, or connect up a 1/8” to RCA cable and plug and iPhone into that aux input. The later is probably best, as then you have an A/B to know it is not the Zdac. 

 

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

reconnect that Zdac.

 

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. 

Dirty? It would not be dirty at 60Hz. Maybe 120, 180 Hz, etc, could be dirty, but the power should be 100% (or 99.9999% at 60 Hz.)

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.

That should not do anything different.

The size and distance does not affect the hum.

 

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

They should not do anything different. Amazon copper is the same as other copper. (It all comes from the dust of stars.)

 

* 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.

Wireless is way higher than 60Hz. But it doesn’t hurt to try and extension cord.

 

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

No. That is the last thing you need.

 

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

I have Zu Def 4s with built-in powered subs. One of them started to buzz. I bought a relatively inexpensive hospital grade isolation transformer made by Tripp Lite. No buzz. Obviously YMMV.