Running supply voltage of 60/60 - Vs - 120/Neutral

Bob bundus;
quote
"in addition to improved line transient protection, your balanced AC supply line offers increased common mode noise rejection over the traditional unbalanced commercial power source."

Could you please explain in more detail.....

This being the unbalanced.
A single phase isolation transformer with one of the two secondary output leads bonded to ground. Thus one grounded conductor and one ungrounded conductor, 120V.

This being the balanced.
A single phase isolation transformer with a center tap secondary winding 60/120V,
60V-0-60V. The center tap being bonded to ground. Two 120V ungrounded conductors with a reference voltage potential to ground of 60V each.

Some of the Sunfire subs are notorious for being noisy. You should contact Sunfire about this problem and discuss it directly with them.

As to the isolation transformer pictured, it looks WAY too small to pass 2000 KVA with low distortion. Then again, it is hard to judge how big the core actually is going by that picture, as there are only the wires and heads of the bolts holding it together to gauge the physical features by. This wouldn't introduce hum into the sub at idle, but it could introduce other distortions at higher power demands. Sean
>

"The input has been config for 240v in as thats what my apc runs on, and output taps 5 and 8, this system was made to be tough,mainly becaus of the sunfire high current draw."

"apc", Apartment
"taps 5 and 8" >>> #5 = 0, #8 = 115V output.
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"The input has been config for 240v"

Then #2 & #3 tied together? With the 240V supply connected to terms #1 & #4?
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2000VA
Agreed more than likely xfmr is to small.
Max safe load of xfmr 2000 x 80% = 1600VA

Check the output voltage of the xfmr with the load connected. The load being the Sub

Jim

The Sunfire amps are quite efficient by design, so they don't pull much current at idle or even during normal use. The only time that they really pull BIG power is when you're throttling the volume with heavy bass passages. As such, the small core Iso transformer wouldn't be causing the hum at idle, which is what Luke has alluded to. Sean
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The APC is the battery backup, 7500 va model, it operates at 208/240 1 ph, i have it set to 240 in and out, and have to use a TX on the output to achieve 120, as you cannot split the 240 on the output of the APC of course, the transformer is rated at 2kva or 2,000 Va, at the current tap im running, the sunfire does humm at idle, but less than say 5db, so its just barly noticable, but lowd enough to keep it from going to stanby on the auto power off, when i plug it directly into the wall the humm seams less, and enough to let it go to standby when not in use, and of course the noise test is done without the low level input connected, and connected sounds the same.