New electrical wiring specifications

HI All, 

I'm going to throw this out there as I'm at baffled with this issue. I too just completed a new home build with a dedicated audio room. The power is fed via underground conduit to the panel. I ran 3 #10 circuits all on the same phase to the room, 1 for my tube mono block amps, 1 for my subs and 1 for the rest of the equipment. The big disappointment is a nasty 60 cycle hum. It's not just limited to that room it's in every outlet in the house! I had a master electrician here 3 times now to no avail. We installed a second earth ground rod on the panel which he claimed should fix it, it did nothing. I also have a Seimens whole house surge protector but have the breaker turned off for it as when it's on the the hum doubles in volume.

At the suggestion from another user I bought the little red Amazon plug in circuit tester. It's showing me I have 7 milliamps going  to ground, Google says this is quite bad. I turned off the all the breakers and that didn't change anything it's still 7ma. It's so bad that when I turn the whole house surge on you can hear the toaster buzz!

At this point I have all three systems (different rooms) plugged into Emotive DC noise units just to be able to use them. Solid state amps can't be used at all that's how bad the buzz is. With the Emotive the buzz is still there just quieter. I know this can't be good long term for the equipment and definitely not for my nerves!

Any suggestions on a next step?

Thanks,

K 

Get a different electrician. 
Start turning off one circuit breaker at a time. 
 

@skyy92677,

Maybe a cable TV line, a ground loop isolator might fix that! See here

Mike

Personally at the distance you almost should consider a new 60 Amp subpanel in your listening room and very short runs to the receptacles.  I haven’t done the math in a while but I did ages ago for a workshop.  The 4 gauge wiring required for the 60A subpanel will outperform 10 gauge at higher loads, plus this way your ground and neutrals join together much more closely and are unable to develop a higher potential like you could with long, separate runs. 

@skyy92677  

At the suggestion from another user I bought the little red Amazon plug in circuit tester. It’s showing me I have 7 milliamps going  to ground, Google says this is quite bad. I turned off the all the breakers and that didn’t change anything it’s still 7ma. It’s so bad that when I turn the whole house surge on you can hear the toaster buzz!

That might have been me, but you are misreading that 7mA!! That’s the GFCI test level.  That is, if you are testing a GFCI protected outlet, and you press the TEST button you can expect 7mA to flow.  That’s very little, but any more and you can stop a heart. 

The important part of that test is to look at the AC and the N-E voltage.

Having said this, if you have  this hum occuring no matter where the gear is you may have DC.  If it’s happening only in the listening room the advice to disconnect any other copper wires like coax and Ethernet is valid.