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persistent 60 cycle hum only on tube gear

I know this topic has been addressed in the past but I'm hoping for the "latest tech" answer.

I have a persistent 60 cycle hum in my ARC tube gear. Not in my Bryston power amps or preamps- just the ARC tube pre and power amps. All XLR. 

I have installed an isolated, dedicated ground system (8' copper rod driven into moist earth) , a Ground Master unit between the chassis and the ground line, I  clipped the ground wire from my 20a 120v dedicated circuit, pretended to ignore the hum (that didn't work well).  I even replaced the tube sets with ARC OEM tubes in the pre and power amps (sonic improvement but no hum cure) .  Still the confounded hum.

Before I spend more money and failing I'd like your personal experience opinion on what worked for you. 

Thanks!

 

yesiam_a_pirate
ghdprentice's avatar
ghdprentice
9,466 posts
 

The only hum I have ever had was created by having some of my system components plugged into one outlet and some plugged into another. I assume you managed to plug them all into the same outlet and the hum still exists... correct? I solved it by getting another direct line from the same breaker box (we have two).

motoraway's avatar
motoraway
68 posts
 

This may be worth a try.......I used a Rolls MB 15b ProMatch converter when I was experiencing a similar problem between amp and preamp. It eliminated the hum completely and to my ears didn't taint the signal path. It's relatively inexpensive piece of equipment. I still have the unit, but it's no longer in use since I've parted ways with that amp/preamp combination. 

 https://rolls.com/product/MB15b

zlone
1,353 posts
 

I am confused, did the problem exist before you established a second ground and/or clipped the ground wire to your breaker box? BTW, pretty sure separate grounds are frowned upon, and can pose some risks.

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