Balanced mains

As said i couldn’t get my head round why, but i have it now.
Also being half the size now, hopefully it wont hum as much or use as much power.

You’re on solid ground now so should be fine.

The part I find trickiest is the streamer. The streamer is part of the Hifi but there’s a boundary where the system crosses over to the rest of the home network. The ethernet switch at that boundary has to be well engineered … unless you put a decent fibre-optic link in there.

We opted to use an OpticalRendu fed by a glass fibre cable from the switch. Our Roon core and music server sit on the other side of the boundary, on a domestic ring main, which works well. If we go for the Grimm MU1, we may need to rethink a bit, as the Grimm will be part of the Hifi.

Best regards, BF

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Strangely, our BPS doesn’t hum at all, despite essentially being a whopping great toroidal transformer. Must be something to do with the black art of transformer design, which is way beyond this mechanical engineer!

Best regards, BF

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I can think of reasons why they are not in wide spread use, in addition to the increased energy losses, size, weight, extra cost and potential for humming, they introduce additional impedance in the circuit, which impedes peak current, offers reduced voltage stability compared to a utility supply, especially the common UK PME supply and your Naim amplifier already has a built in isolation transformer.

I certainly would not run one in balanced mode, I would want one side of the secondary winding, lets call it ‘neutral’ earthed.

They certainly get a good review when you look into it all, i like the way they cancel the noise out off the mains without using filters, etc.
Plus massively cheaper than mains conditioners, that can seriously effect the dynamics etc.

Plus recording studios, hospitals etc use balanced mains, well anything that needs as good as it can get mains supply, use balanced mains, so lets hope it does what it says.

Plus i dont have any naim transformers to worry about these days, just a huge 2.2 kva in the vitus

you won’t be disappointed.
I installed a BPS100230MP and think it’s one of the best upgrades to date.


Why do Naim not recommend such devices then. Maybe we could get an opinion from @110dB
Increased line impedance ==> not good perhaps?

I suspect there are safety issues as well as hinted upon by bluesfan

That’s a big one lol, do you need such a big one for your system?

Do naim not recommend balanced mains then ?
I know they say power conditioning is not recommend, but then some do and like the results.
Not that it concerns me these days, but i am sure others would like to know the official stand on it

Hi Dunc, these are not new ideas. Shame the old forum archive is so poor and practically unusable. There are threads on there with massive equitech balanced transformers with a lot of raving going on.
I don’t think Naim objected to them as such. I guess they do not get involved due to possible safety implications of which I am not completely knowledgeable to comment.

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I know its not a new thing, i never bothered before, but i feel i am at a point now that i feel i would like to explore it, especially as its quite cheap really, especially against other things like this.
Just wounded if naim themselves had committed on it, looks like they haven’t.

I doubt very much you will get a positive response from them on here, but could be wrong

As said it doesn’t concern me these days.
But i probably should have explored it years ago, especially with the humming i have put up with over the years, with all the boxes talking to each other, lol.


Ah the well loved Naimian chant :rofl:

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The first point is why ideally they should be rated the same as the circuit or higher. Between you and the power station there are many transformers and that number varies massively depending on location. An additional one, if sized correctly, makes little difference.

As to the second, no Naim do not have isolating transformers. They have internal step down transformers like any product. The point of a BPT is to not pass common mode noise and offset to the transformer in the audio equipment. Thus letting it operate without saturating the core or feeding unnecessary common mode noise into the unit. Although all linear power supplies provide this isolation, once the effects of offset and noise enter the case it’s too late.

Steve at Naim mentioned in the other thread that Naim use nothing at the factory. And at home he has no special mains arrangement of any kind though other staff do, he wasn’t aware of any BPT.

well Dunc, as you said, a large surplus of power is good :slight_smile: (and indeed sounds very good, without restrictions)

Hospitals use ‘Isolated power supplies’ i.e. transformers plus some electronic earth fault detection relays (IPS units) in critical care units for patient safety. It allows a single fault to occur (the electronic earth detection relay raises an alarm) without putting patients lives at increased risk, they do this because the alternative, a very sensitive RCD, could lead to the electrical supply being disconnected at an awkward moment when on the operating theater, not a great thing!

Studios use them for avoidance of earth loop issues which are more likely in a studio due to the ad hock nature of their ‘patched’ systems and the vast amounts of interconnected equipment.

They would rather not need them. It has nothing to do with supply quality.

This is an isolating transformer, the secondary winding is not electrically connected to the primary, just as in most amplifiers which use linear power supplies, why would you need another.

Of course, but the one up steam of my system is typically rated at between 300kVA and 500kVA not 5 or 10kVA. Why would I want the additional impedance in the circuit? I grant you the effect is not great but it does not improve current flow.

You’re missing the point. I’ve said they isolate. But by then it’s too late. Offset causes the core to saturate and misbehave generating EMI. An isolating transformer moves that problem to the isolating transformer itself letting downstream transformers to run offset free. Ditto common mode noise which, although physically isolated from the opposite windings has made it into the enclosure and can be transmitted as RFI.

This is why sensitive scientific and medical equipment also uses them.