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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

Showing 2 responses by 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.
ngjockey OP
1,042 posts
 
In a DIY setup, I would suggest using a GFCI on the output. They work by comparing the hot to the "neutral" with a differential transformer (usually two). GFCI's are intended to protect people instead of equipment but, technically, the equipment would not require additional protection.

When the power switch opens either side, it's still off because there is no circuit. The only danger is if you stick your fingers inside an open cover while it's plugged in but that doesn't change either way. Both 60V sides of a balanced system are protected by the same unbalanced breaker upstream of the transformer.

What I'm trying to say is you don't have to turn it off unless you're poking inside.
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