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Balanced power compatabilty census

I have run across some equipment that does and does not work well with balanced AC. I thought this forum might help others, if supported. In my case, I used 5KVA transformer and one piece of gear at a time.

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If you are unfamiliar with "balanced AC", it refers to 60 volts +/- as referenced to ground and hot/neutral are 180 degrees out of phase. Normal (North America) power from outlets is 120V on hot leg only. Equi=Tech, Balanced Power Tech. and DIY projects convert single phase to dual phase with the "promise" of reduced noise. In some cases, sonic improvemnt can be more than just reduced noise. In other cases, the grounding scheme of the equipment may not be compatible. Don't jump to conclusions that because one experience or model worked or didn't, that it reflects on the brand or type.
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Genesis Stealth amp did not work properly but I suspect problem is due to active x-over.

Plinius SA100 mk3 worked better but no better than simple isolation.

Sonic Frontiers SFL-2 loved it and had immediately noticeable improvement.

Manley Snappers sounded compressed with balanced AC. Odd for differential amp.

I have yet to try with sources which have separate isolation.

Does anyone else have have positive or negative reports?
ngjockey
ngjockey OP
1,042 posts
 
Zaikesman - That's what I thought too and was surprised when it didn't work that way for everything. That's why I started this thread.

Trust me, that 5KVA transformer is not starving anything for power. It is capable of sustained 20 amps in balanced configuration and weighs 120 lbs. The amps I used draw in the neighbourhood of 5 amps at max.

I think it has more to do with how a piece of equipment in grounded internally but I'm not an engineer. Granted, most commercially available products are undersized for amplifiers.
zaikesman
3,017 posts
 
I'd research the forum archives to see what you can find on this subject (and look for contributions written by Sean).
darkmoebius
900 posts
 
The power transformers on my Welborne DRD 300B monoblocks would audibly "buzz" when I plugged the amps into 2.4kVA Topaz Ultra-Isolator trannis wired in balanced config. It was actually so scary that I would have to unplug them after only 5 seconds.

After weeks of frustration, I shipped them back to Welborne. Embarrassingly, the problem was so simple I could have fixed it myself withing two minutes if I had just calmed down and thought it through - the star-grounding just needed to tightened slightly.

Since then, quiet as can be. No problems with the rest of my components, either.

Just remember to turn off the power at the transformer when not in use because the component's own power switch will only turn of off half of the 120V in 60V-0V-60V configuration.
zaikesman
3,017 posts
 
Darkmo: That last comment I think warrants some elaboration -- my components (except power amps, which don't get the balanced AC) that go on semi-powered standby as well as those that turn all the way off seem to behave the same (meaning the way you'd expect) regardless of whether balanced AC is selected at the Power Wedge's iso-trannies...
darkmoebius
900 posts
 
I had a feeling I'd get called on that this morning, Zaikesman, and I'm glad you did.

My comment does not apply to any consumer balanced power products(I assume), only people like myself who bought commercial/industrial isolation transformers and then rewired them for balanced power.

Ok, let me try and explain it as an electrician told me when I was wiring my 2.4kVA Topaz Ultra-Isolator transformers. (anyone more knowledgable please step in to prevent me from passing flawed info)

In normal 120V(0V-0V-120V) wiring, one wire is neutral(0V), another ground(0V), and the third carries the full 120V. Flipping the component's On/Off switch essential connects or breaks the 120V line. So, even turned off, the neutral and ground line are connected.

In balanced power (60V-0V-60v), the same component switch will only disconnect one of the 60V lines, leaving the ground & other 60V connected. So, even turned off, the component will have 60V flowing into it.

For that reason, the electrician advised me to place a switch in the cable feeding(0V-0V-120V) into the balanced transformer to cut the power to everything.
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