High Efficiency System- Noise Floor Reality Check?


Trying to gauge whether I'm expecting too much quiet with the system at steady state, ie idling, no music playing. System consists of Avantgarde Duos, with the latest version of the Audiopax 88 monos; Steelhead preamp running a single phonoplayer (The TT, arm, cartridge and wire to the preamp will change in about a week).
Everything is plugged into a pair of Shunyata Hydras- two separate units, one for the speaker/amp woofers (Hydra two, with two outlets; the other a Hydra 6, into which the Steelhead and Audiopax amps are plugged). Using fairly high grade Shunyata power cables on everything; the Hydras, in turn, are plugged into a Richard Gray Substation, a 240v step down transformer that has its own line.

What am I hearing?- well, if you put your ear up the tweeter or midrange horn, a soft 'zzzz' type electrical noise, and from the woofers, a muted 60 hz hum. From the listening distance you can't hear it at all. And, when you crank the gain up on the preamp, no music playing, these noises don't get any louder.
Am I hearing the invariable low level noise of electrical equipment through very efficient speakers? I'm not so anal as to believe I can eradicate all system noise on a set up of this type, but I'm concerned that even this low level of residual noise may interfere with the system's musical capabilities. Would love to hear from high efficiency types since this is my first horn based system.
I also have a good electrician who has helped me in the past, but I'm not sure there is anything he could do beyond this to improve the noise factor, is there? Reality check? TIA.
128x128whart

Showing 3 responses by whart

Well, you guys represent the extremes of the internal debate I have been wrestling with- it shouldn't bother me, but I don't like knowing it's there.
FWIW, I have already tried virtually every permutation I can within this room; I have yet another set of dedicated outlets that take from a leg of the 240 line that feeds the stepdown transformer, but this may still be affected by what's on that line, i guess.
As to the differences in electronics, no doubt you are right, Herman- the Audiopax amps are, as far as tube rush goes, quite quiet. But, there is that hum. Damn!
The only way to know for sure is to have another completely separate subpanel, with 20 amp lines set up and run into the room. So, I'm going to probably talk to my 'guy.'
Oh, and the sound at the listening position does keep improving. At first, I refused to invite the devil into the system by way of a CD player to break things in- so I was doing speaker break-in the long way, through playing and listening.
Then, I got impatient, so I hooked up a little portable and found my copy of Art Zoyd's 'Nosferatu,' a virtually unlistenable little sonice nightmare that is perfect for breaking stuff in. Let that run for a day or so;
still fiddling with speaker position and woofer settings, but the bass on a good recording is impressive and musical, if not real. (Again, went to a club last night down in the lower east side and listened to a couple bands- the kickdrum is impossible to duplicate, at least in my smallish listening area with this somewhat 'modest'system).
Thanks, all. :)
Well, no joy yet. Got one of those Granite Ground Zero thingies, it does work, but it is not solving my problem (yet). In fairness to the manufacturer, I don't want to suggest that I have reached the end of all possibilities in using it- for example, where does one find a ground on the Shunyata Hydras? Those are the only 'components' in the system that have not yet been routed through the Ground Zero.

I also tried: removing everything plugged into the step down transformer other than the hi-fi system Shunyatas- no difference; running the Shunyatas into conventional outlets in the room that have nothing to do with the step-down transformer (and pulling the plug on the step down transformer as well). No dice.

My electrician came by yesterday- at first, he looked at me like I was insane for complaining about noise that you hear by putting your ear close to these big speakers- but, after a few minutes he acknowledged that he could hear it in the room, sitting nearby the speaker, not right on top of it.

He is of course willing to install a separate subpanel for 240, giving me the option of either leg to experiment with and setting up yet another group of dedicated lines with an isolated ground. This will involve some cost and some breaking of walls~ so i've been trying to find solutions short of that. The killer, though, would be for him to do all this work, and for me to still have the hum.

I suppose he could rig up something temporary to see if it does the job, but the distances are more than 50 ft. from the main panel to the room- and three floors up- I wonder if he has a really long extension cord?

Any further thoughts on this, gang?

BTW, got a Monaco amp stand with the carbon shelf and footers from a fellow 'Goner yesterday- wow! Sort of like
taking your car out of the mud and driving it on smooth, fresh pavement. The fact that it is gorgeous doesn't hurt,either.

This noise problem is driving me a tad crazy, though.

(OH, yeah, I'm supposed to get my new TT today too, so
at some point, this system is going to reach its potential).
Thnx Doug. Interesting angle. I'll call my buddy Jim Smith about that- he was the importer 'til recently.