[avalon65]

Greetings! I am the second owner of Stratos with cap upgrade and I've had it about 7 months. When I bought the unit I had it shipped directly to Klaus for a once over and update the transformer. I think this buzz/hum has always been there but I've been upgrading equipment with secondary hopes that the changes would solve the problem. Now that I've completed my changes, I'm chasing this issue. The buzz/hum is audible from about 5' away from the speakers in a dead quite room. I've read numerous other forums/posts about ground loop issue and have followed various recommendation. Here's what I've done do isolate the problem.

One by one I've disconnected ICs and power cords from the various sources to concluded that the only time the hum disappears is when no ICs are connected to the Stratos. As soon as I add the ICs (lower grade Gronebergs)  to the amp end (other end of ICs are not connected to anything) the hum returns. It's like they are acting as an antenna. So then I tried a pair of MIT 330 plus ICs with the same result. As a last resort I tackled the power cord, which is plugged directly into the wall and added a cheater plug to the stock power cord. Notta. Then grabbed a 40' garden variety 14 AWG extension cord plugging into an outlet on a sparely used circuit. Again no luck. BTW I do not have cable TV. Any other suggestions? Better IC's? Better PC? Power Conditioner?

Thanks!

[rosconey]

call klaus

[DARTH AUDIO]

If it's not the amp you might have a ground loop problem. Is the sound more of a buzzing than a hum? Check out this web site: http://www.graniteaudio.com/zero/index.html
Also try this web site to help find the problem:
http://www.psaudio.com/toolbox.asp  click on Humbusters..

good luck..

[W.C.]

Another thing you could try is take your amp over to a friends house and put it in his system to see if you get a different result. That would tell you if it's the amp or something else.

[Barry]

Avalon65

I suspect it is ground loop problem as the noise disappear when IC is not plugged.  So the source of noise is not from Stratos itself.  I have some hum noise but not as serious as yours.  I'm working on eliminating ground loop with balance power supply.  But before you try anything expensive, please do a simple test.  Unplug all connection to cable TV plug or other TV socket and give it a try.  Most of the ground loop problem is caused by a different reference ground in TV system.  

If the Hum sound disappear, then you can buy a small device which basically a small isolation transformer to isolate the TV socket ground from the system at very low cost.