Currently there are no multi-outlet adapters plugged in, as the PurePower APS has 8 outlets.
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This is the interesting thing: both AC regenerators affect products that are not plugged into it. I even dug out a dusty Jolida mosfet-hybrid amp to determine if it was an amp incompatability.
The Jolida was plugged directly into the wall and turned on. No buzz occured. Then, the PurePower APS was turned on. Buzz occured.
The good thing about the PurePower APS is that it has a battery backup operation. Therefore I can unplug it from the wall in order to test:
1. Left amplifier is ran straight to the wall outlet.
2. Preamp is ran straight to the wall outlet.
3. Left amp and preamp are powered on.
4. There is a soft pink noise, like tape hiss. Normal.
5. The PurePower APS is unplugged and powered on in battery-backup mode, turning on the source component.
6. Now there is a slight buzz signature coming through the speaker.
7. Now the PurePower APS is plugged into the wall, switching it out of battery-backup mode.
8. Now there is a strong buzz signature coming through the speaker.
Therefore, I suspect the sources of buzz contamination are twofold:
1. affecting the components in which are plugged into it, by making the components themselves buzzy.
2. dumping noise into the ac outlet, making all components on that ac circuit buzzy.
The quietest buzz occurs with all inputs disconnected except for the DAC. Still present, just quieter.
My last ditch effort will focus on the preamplifier. I will install those RCA input caps on unused inputs.
