XPA-100 Noise floor .. hiss i don't think it can removed

[vegasmassimo]

I have a pair of xpa-100 monoblocks they are i think about 60 days old

I have Klipsch Chorus 1 speakers very efficient horn loaded.

I have amp noise.. I cant seem to track it down... its like a very soft 60 cycle and white noise combined

I have expert level audio skills, I have tried the following

with or without pre-amp on,
different cables to the pre-amp,
disconnected from pre-amp (just cables),
with out cables connected to the amps

Even without anything but speakers connected to the amps, There is a lot more noise (hiss and hum) than I would expect from home hifi.

This low level noise is a baseline it does not increase with the volume, so its not so noticeable when playing music but its there, always there, hissing and humming in the background. -- both Amps, when used together or having one on the other off ..

would a power conditioner possibly help
If so what size would I need (2-xpa-100 + 1-xpa-2)
Brand and Model # please ...

I am adding an xpa-2 to bi-amp my new speakers next month (JBL 4350 a 4-way speaker designed specifically to be bi-amped)

These will be mine and run with 2 XPA-100 and an XPA-2

[goozoo]

Are you using XLR or RCA interconnects? I would use XLR interconnects in this situation. Have you checked your speaker cables/connections? Poorly connected speakers result in low level hiss sometimes. Is everything plugged in to the one outlet in the wall as in your picture? How many amps are you drawing and what is that wiring and plug rated at? A power conditioner may not help much if the above is true.  BTW, where are the horns in that picture?  

[mshump]

I can't help with the hiss situation,but that is one sharp set-up !! (drooling)

[garbulky]

+1

[Gary Cook]

Not many people have speakers bigger than their panel

BTW I have an XPA-100 running my sub and it has no hiss or hum. It is connected via a 6 metre XLR to a USP-1.


Cheers
Gary

[AudioHTIT]

An XLR connection might help with the hum, but with speakers that efficient I think you're running into the noise floor of the amp with the hiss. Normally, having shorting plugs on the input of the amp will make them as quiet as they're going to get. The XPA-2 has an 8 dB better noise spec at 1 watt which is what you're interested in, it could even be a bigger difference because the XPA-200 is 89 dB A weighted and the XPA-2 doesn't specify weighting, it could be 97 dB unweighted. The XPA-200 just might not be quiet enough for those speakers.

So you're bi-amping with the XPA-2 and 200? If so you might try the XPA-2 on the highs, it could sound quieter that way (where do they cross-over?). I might just run the XPA-2 full range for the whole thing and be done with it. The XPA-2 will likely be noticeably quieter, if you really want to bi-amp maybe get two of them (you could then also go vertical bi-amp and have short speaker cable too).

Unless you're power is really bad I don't think a power conditioner will help with hiss.