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

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
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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.

but i am bonding the ground to everything, from the chasis, to the transformer casing, to the outlet it self on both pri and sec sides, and did run a #1Odd welding cable to bond directly to grounding rod, and this still made no diff, i am moving next week to an apt. and will re-evaluate the system then, i will then do tests to see if this setup does endeed kill the dynamics of the systms sound, as that is what i heard you get with a lot of power filters, as right now this is basically what the service goes through before it hits my equipment:

240V main service into home into primary filter which consists of 1 large inductor filter per phase, then a high energy surge protector, then a small filter cap to ground per phase, after that it runs though the main panel to a dedicated 30 amp 240v circuit upstairs into the "APC" (battery backup) in that it filters the power again, with numerous Torrid filters and filter caps, then it drives the power through SCR's to process the frequency and voltage, (no normal bypass as some battery backups do) then it leavs the APC and goes into my home brew dist block, (the large grey thing next to the apc in the pictures i have up)there it runs though the isolation/step down transformer, then it pases through the EMI/RFI filter (both legs), then to the outlet. and meanwhile the same ground on everything, everywhere.