I would think so. I do not have any integrated units with USB so only have the OPPO to go by but it is dead quiet between tracks when fed via USB. Have you tried playing something from a thumb drive?

It only makes the noise when using the USB input?

Does it make the noise when the usb is selected as the source with nothing plugged into the USB input? You may have to crank the volume a little to hear it but it should be silent.

With the USB cable removed from the amp, the signal is dead quiet with the volume cranked all the way with USB source selected.

Yes, this noise is evident only when using the USB source with the USB cable plugged in.

Try it again with the usb plugged into the amp but not plugged in to a source. Just trying to eliminate the amp as an issue. Try several usb cables if you can.

Does the transformer noise you discussed on the other thread still exist? Why are you using the surge only side of the APC?

Looking at the manual for the RR2150 the amp should not be plugged into any switching outlet such as those found on your APC UPS (all of the outlets on my APC are of the switching type). If you could, try running an extension cord from another room for the Outlaw and see what if anything that might do for the transformer noise. Surge suppression should protect equipment from external sources but does not necessarily protect from other gear on the same surge suppressor. Plugging the RR2150 into its own outlet away from the APC unit would be a good start. With everything plugged into the same surge suppressor a ground loop or feedback noise from the computers power supply is quite possible. The outlet on the APC marked specifically for the system unit is filtered to prevent power supply noise from effecting the other equipment. In the days of CRT monitors it would show itself as static on the monitor.

Do you have one of these by any chance? Checking outlets for open grounds and polarity issues might give us some clues.

http://www.amazon.com/gp/product/B005GYB...BR13TGS6KDGYRHY

Keep the faith and we will figure this out.

The noise goes away entirely when I disconnect the cable from the USB hub but leave it connected to the Outlaw's USB in.

http://www.amazon.com/APC-Retail-Battery...asin=B002QR7DHS

I am using the "surge only" side of the UPS because I don't want the amp to suck capacity out of the batteries for the computer if I get a power failure. I have the amp plugged into the non-switched (not controlled by master), non-backup portion of the UPC (lower right in the photo). The computer is plugged into the backup side of the unit (left side). I don't have anything plugged into the "Master" outlet (top left in the photo.) Nothing is being switched from the UPS.

Yes, I do have one of these. The outlets tested "CORRECT":

I'll get back after trying a different outlet.

Knowing the outlet is good is a great start. The spec sheet for your UPS shows the max power output at 780 watts.

You might just be on the edge of the max output rating for the unit. My APC unit does have facility to shut off the power to the surge only side making every outlet a switched outlet. Yours may be different.

The transformer hum on the Outlaw is evident when the amp is idling, no signal, drawing little power. The USB noise, the same. So it is unlikely that the UPS is creating any of this because of its 780 watt capacity limitation. The idle draw of the amp is 5 watts; full load is 400 watts. The power supply on my computer draws <150 watts. Nothing else is plugged into the UPS.

Is the hum from the transformer or is it a ground loop hum from the speakers? Does the transformer hum with the speakers not connected?