Checking the AC polarity of your amplifier

Nsgarch, initially I found that leakage voltage measurement failed to be a guide for better sound, but the ultimate problem I had was with hum with phono caused by the ground of the turntable not really seeing a ground when plugged into the Equi=Tech. When I plugged directly into the wall, I had no hum. This turnout to be caused by my not having everything plugged into the Equi=Tech. I did not have my big subwoofer amp plugged into it.

John Tucker has suggested that the ground fault circuit on the Equi=Tech is responsible for my problems and suggested that I remove it. I just gave up and sold the Equi=Tech.

Running balanced AC to some gear and not to others within the same system is the same thing as introducing a ground loop. That's because the difference in voltage potential from hot to neutral varies with the way that each component is receiving their power.

In one method, you've got 120 volts of potential on the hot and the neutral tied to ground. In the other, you've got 60 / 60 volts divided between the hot and neutral. This is why filtering inside the gear becomes ineffective when used in balanced mode i.e. neutral is no longer at ground potential but has become an active part of the AC feed. Since most filters shunt the noise to neutral or ground, you've removed the "dumping ground" for the noise from the equation. This means that the noise remains in the gear and further contaminates the other components tied into that same balanced AC feed.

Once again, all of these types of systems introduce further non-standardized variables into the system. Rather than opening up the door for more problems, why not just optimize the standardized system that you've already got and we've been using for years? Using this approach, you're guaranteed that your components will work optimally with little chance for negating built-in design features and circuitry.

Until gear is actually designed and built to be run strictly on balanced power, introducing balanced AC as the source of power will provide rather unpredictable results in any given system. Sean
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For everyone's info, and for what it's worth vis-a-vis our discussion about mixing balanced and unbalanced power:

I had about an hour and a half conversation with Brent Jackson (who is the CEO, chief engineer, etc) of ExactPower on this subject to see what he'd say (especially since I use both of his units, the EP regenerator and the SP balanced unit -- and do so only because I'm in an apartment now. When I had a house it was dedicated circuits with high-speed diodes on the breakers for surge protection and that was it!)

Anyway, his recommendation for using both units together was to put the EP regenerator at the speaker/amp end and plug in the amp, both (CLS) speakers, the subwoofer, and (using a longer 12 ga. PC) the SP balanced power unit, which I have near the source devices.

First I listened with all ground pins connected. It was pretty quiet except the sub which had some barely perceptable 60 ~ hum. So I started putting ground lifters on the devices plugged into the regenerator. That got any residual noise/hum, so I haven't messed with polarity yet on those devices (but you know I will ;-)