Help with buzz / hum that's making me insane r

Stubby:

When I connected the Shunyata wall outlet I noticed the ground had been floated, so I reconnected it to the shunyata outlet. I'm fairly new at the idea of playing around with power, so am I correct in thinking you mean I should remove the ground (green wire) from the shunyata duplex? I was told this was dangerous, so if you or anyone can chime in, that would be great.I may be misunderstanding what you mean by "lifting the ground", in which case I'd be grateful if you could let me know how to do this. I do have video equipment connected, but powered it down and disconnected from mains and that didn't do it either.

Thanks everyone for your responses.

Sonofnorway: the only interaction between my video and audio setup is I have the audio of cable going through the integrated with a humbuster rca pair. I disconnected the that rca pair and unplugged all the power of the video setup (plasma screen, brain, cable and dvd) from the wall and the hiss was still there. I didn't unplug the cable from the cable box, but there was no power going to any of the video gear and they weren't linked to audio setup with any ICs.

Nick778: thanks for the clarifying question. It's definitely a hiss that also has a very slight fizz to it, like a digital hiss. It's only on the dome tweeters of the Dali's; the ribbon tweeter and other drivers are dead silent.

Apachef1: On the same circuit I have my NAS for my media server, a Cable modem, a printer, a phone and two lamps, both non-halogen. All kitchen appliances (fridge etc) are on a different line. (I can't install dedicated lines, FWIW).

Hififile: No dimmers, but kitchen apps are on a neighboring circuit. It's a condo in 50-unit building. I don't think my breaker box has any screws to tighten--it's all just breakers w/switches, but I'll check.

Herman: The only problem is that this is a new thing I'm experiencing. The hiss may have been there all along and I'm just now noticing it, but the way it manifests itself in listening is that vocalists with higher-pitched voices, or violins, etc have a very, very subtle distortion. So, vocals that seem to me like they should be crystal clear in production (annie lenox, etc) have a very slight throatiness to them. In most cases this just sounds like texture to me, but sometimes sounds like distortion. Again, it's very subtle and it could be that all the upgrades have made my system more revealing and I'm hearing things I wasn't before that sound like slight distortion but are just texture; however, I'm perplexed and do want to get to the bottom of this. I notice this more on voices in the middle of the soundstage. All other frequencies sound frigging amazing, and not all treble sounds this way, so it could be psychosomatic, but I would like to figure out if there's an issue or I need to adjust to my system. Sure I'm not the first!

The amp is dead silent. I just disconnected everything, save the amp and threw the breakers on the rest of the house and the hiss was still there. Then plugged in sources one by one, then added video section--still hiss. Then powered up rest of house--still hiss.

The hiss is only audible with ear next to speaker (the same was the case when I connected different speakers, so it's not the speaker, and the hiss was there with different amp, so it's not the amp).

I'm realizing I may be a big huge idiot. My wife feels, and she has very good ears, that this is just a more revealing system then any I've had, so voices actually have texture, as opposed to always sounding pristine. I can't imagine it's a ground loop, since I've disconnected everything and the sound is still there. The sound of my system is amazing, so maybe I'm trying to hear something that isn't there, which may be true because I don't notice it on all recordings. Can this hobby drive you crazy or what! If others can chime in as having experience this, or it being normal (as has happened in this thread) then maybe I need to trust that advice.

Thanks Rockvirgo, I am moving the carpet tomorrow. Can't believe I never picked up on it. I have been, and am still VERY happy with my system; however, in thinking about my hiss issue, I've decided there are two separate things going on:

1) The tweeter hiss is perfectly normal and only audible if ear is at tweeter
2) I could have a sibilance issue do to recabling and adding new ICs

Assuming the sibilance is cable related, I guess I'm wondering what to do. I didn't notice it before installing the Nordost cables, so I will swap them out and see if that is the issue, although I'd be surprised (wouldn't be the first time). If that's not it, I'm wondering what my next step should be. My speaker cables are 3 meters, which is more than I need, so I've got the excess length coiled under my stand. I had them this way before the sibilance became an issue, although I did recently remove them and put them back in, and I know purist cables are thought to take a while to settle back in, so maybe it's just a waiting game.

If it's not the SCs and not the ICs, then what next? From reading other descriptions of this sibilance issue from other people on the net who've experienced it, I'm pretty sure that's what's going on.

Should I clean my connectors? cap off any unused inputs on my integrated?

That's what I'm going to do this weekend hopefully. I talked with Grant from Shunyata who was extremely helpful and am going to test out some other things as well. I gotta say, I am blown away by how much time Grant spent with me, and how insightful he was. Excellent customer service.

Thanks mapman. It's on digital and vinyl. My theory, which I'll be testing this weekend, is that it's a cabling issue. I didn't have this issue prior to taking my system apart and reinstalling it in a different configuration. A number of people (grant from Shunyata included) said that this may dissipate over time as things settle back in, and could also be because I have my 3 meter purist Speaker cables coiled around eachother under my rack, which is stupid. I'm going to change that this weekend, clean all contacts and plug any unused inputs/outputs and then see what happens. If that doesn't do it, then I will start at the very beginning and do a methodical sweep of the system to isolate it, bringing in a different amp if necessary.

I'm going to post my results from my experiments to solve this issue, that way it could maybe be useful for someone else who finds themselves in the same predicament.

I've thoroughly tested all equipment, bringing in alternate pieces when necessary (speakers, integrated amp and cd player in place of media server) and the issue doesn't change, so it's not the usual suspects (amp, source or speaker). I shut off the breakers to the rest of the house and verified it's not an appliance on another line. I've tried a variety of recordings to make sure it's not just an issue with one recording.

Following the advice of Grant from Shunyata I uncoiled my speaker cables and ran them straighter, without any coils to the speakers and let them settle back down. This was the first thing to have positive sonic results in my experiment. Sibilance isn't gone altogether, but treble sounds more open with zero distortion. Playing Marie Laveau from Kenny Barron's "Things Unseen" Album, the trumpet sounds still a little piercing, with sibilance on highly extended passages, but better than it before. Then, I took out my Nordost IC and took it over to my dad's to test it out in his system (this is the newest cable I added) thinking maybe something was up with it, but it sounds frigging amazing. I bring it back home and do an A/B with the purist IC and sure enough, the sibilance is only noticeable on recordings like the kenny barron that less than stellar trumpet production work (IMO). So I think it comes down to the Nordost being a bad match for the Dali's. When I first put it in, I was really in love with it, and I'm feeling a bit foolish for being so quick to jump up and down for joy. I think the Dali's are just too forward for the Nordost, which is a bummer because I love this cable. In any case, I still plan on doing a connector cleaning and further isolation tests to make sure, but I'm heaving a pretty big sigh of relief.

Thanks everyone for your help.