Any thoughts on balanced power?

[Wayne A. Pflughaupt]

I picked up a balanced power supply from a medical facility something like 18 years ago but never got around to using it in my HT system (for a variety of reasons I won’t bore you all with). The system is rated for 12 amps, according to its on-chassis labeling.

I’m finally in a position to utilize it, but have been hesitant. Gear has changed a lot in the last 18 years, and I’m concerned that modern HT receivers and pre-pro’s, with all their microprocessors and sensitive electronics, night not take kindly to it. Is this a legitimate concern or not?

Second, if the consensus is it’s fine to use, what about mixing in components not connected to the power supply? I’m thinking I’d like to keep my subwoofer off it and plugged in to standard wall power.

Regards,
Wayne A. Pflughaupt

 

[TNT]

I would run all or non on the trafo.

Balanced Power Isolation Transformer

Hello, everybody! I want to build a line isolation transformer, as when bombing infrastructure in my country appear, there are days when there is good electric line and some days i cant listen to anything because of the hum on transformers on my devices and signal, and unwanted oscillations...

www.diyaudio.com

No warranties

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[JLM1948]

I picked up a balanced power supply from a medical facility

Are you positive that it's balanced? Medical equipment is often powerd from a floating iso transformer, which is somewhat diferent, particularly because it's extremely safe, which is not necessarily teh case with balanced power.
Anyway, in most cases, good earthing negates the need for balanced or floating power.
Iso transformers are good at eliminating hum loops, but in a HT case, they would simply not exist if all the equipment was powered from a single outlet.
OTOH iso xfmrs can do almost nothing about buzz and clicks; only a proper filetr, or better an inverter can clean power efficiently.

 

[TNT]

My trafo, which is no commercial product but a special order, is balanced i.e. outputs 115+115 V and completely floating from the mains.

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[JLM1948]

Making it balanced requires connecting its center tap to the earth of te receiving equipment. Without it, it is floating.

 

[TNT]

I use no mains earth in my audio system. I have in fact removed all the safety earth pins in my distribution sockets, connected to the secondary side, in order to secure that no audio units has safety earth connection via their power connectors.

I have the option to connect the electrostatic shield S to primary mains earth. I have preferred this.

Audio units do share their signa grounds of course but no power ground and obviously no earth..

I suppose it look like this:

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[JLM1948]

So it's not balanced power, it's floating power.
I think you can expect better performance noise-wise, with the equipment earthed.
Screen to safety earth is good.

 

[ddude003]

Seems to me that there are many a manufacture of Preamplifiers and Amplifiers that suggest one not use "power conditioning" and should connect directly to a proper rated power outlet... For all other peripheral equipment, such as CD/DVD players, DACs, Streamers, as well as telco and network gear, can use power conditioning to great effect... And this is how I roll...

 

[JLM1948]

Many simple power conditioners are just EMI/RFI filters. If the equipment has been properly designed, EMI/RFI protection should be already addressed. Adding two such filters is not damageable, but also not significant.
There are some cases, as that of the OP, that require more than filtering, actually reconstructing the waveform, either for short durations (<50ms), which can be addressed by passive means (capacitors and inductors), or for longer durations, which require active solutions (battery+inverter).
In all cases the equipment should be earthed.