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 1 response by tubes108

Just a point of reference regarding the Audiopax monoblocks and the Art Audio PX 25 amplifier. I've had both in my system driving Duos. Both are fantastic products. Although the 'Pax are quiet, the Art Audio PX 25 amp has a significantly lower noise floor. The Art Audio could be the quietest tube amp around.

Some people talk about a desire to achieve a noise-free "mystical" blackness where music appears against a noise-free background. Using the PX-25 with my Basis Debut 'table (w/its hydraulic suspension that keeps the 'table immune to outside vibration/noise) this blackness was achieved which adds significant enjoyment. Hearing low level details that would otherwise be missed, and to hear every note played during fade outs is a thing of beauty.

For high efficiency speakers such as Avantgardes, be sure to get the low voltage input option on the Art Audio PX 25.