Is it a hum or more like a hiss? I experience, well, not only me but other zbox owners as well, a sort of hisssschhhhh sound. I believe it's from the power tube. It's intermittent during warm up, and after that it's gone.

M  ;)N

It's a high frequenzy sound so it seems it's coming from the tweeter. Possible scenario/problems for the continuos hissing sound could be:
1) There's a cobra inside your speakers and it doesn't like the music you're playing, hence the hiss. (possible solution: call pest control, you can't handle them, they're poisonous)
2) Tube instability (what tube do you use?)
3) Unshielded interconnect (obviously use a shielded one to address the problem)
4) No clue, like the rest of us? (call Steve, he might answer your call or your email. With your name who wouldn't be scared not to reply)

M N

No, I can't hear it over the music and have to be within 3 feet to hear it which I realize will never be a listening position in reality.  Just knowing it's there bugs me and I was just wondering if it was some what normal.  

Thanks

[quote author=lshawn666  link=1166324094/0#5 date=1166446311] Just knowing it's there bugs me and I was just wondering if it was some what normal.  

Thanks [/quote]

I guess it's normal, just like having a beautiful wife and of course a mother-in-law!

M N