Balanced power

[ThomasW]

Balanced power? What is it.

An isolation transformer having two output windings, configured as a center tapped push pull. The safety/chassis ground is connected to the center tap, and the hot and neutral connections are now balanced push pull. As a result, with whatever Y caps are used on the line, the low frequency current through the cap is balanced and cancels nearly perfectly at the chassis ground (center tap)

In North America/Canada/Mexico, etc one ends up with +/- 60 VAC instead of +120/-0 VAC on the hot and neutral AC wires



What does it do?

1) Improved ECM (electrical common mode) rejection (aka decreased problems from ground loops)
2) Improves sound quality
3) Improves video picture quality

Start with the Equi=Tech FAQ. Equi=Tech basically 'invented' balanced power
www.equitech.com/faq/faq.html

How to get it? Well IMO the best way is one of the "Q" trannys in a box.

www.equitech.com/products/specials.html

The picture below is what one gets



This is what Chasw98 said after installing one of the Equi=Tech "Q" trannys

I am quite amazed. The first thing I noticed is that the power supply in the HTPC runs quieter. Significantly quieter. Then I powered up the rest of the system and it was very quiet. Too quiet, I wasn't sure it was working right. I put a CD on and it sounded better. Then I stopped the CD and ran the volume up to 0 on the pre/pro which is calibrated at 85 db SPL. No f*?%$ing noise, I mean none, even with my ear plastered on the tweeter or mid range driver. Then I ran it up to +10 db, still no noise! Simply amazing. Everything I have played on it seems to be tighter. I'm not sure how to describe it but another veil has been lifted. Just to be sure, I turned everything off and moved the plugs to the other set of dedicated outlets and all the "stuff" that had gone away came back. I am a convert. The money was well spent on a significant change for the better in my system!

Here's a link to a few lower cost DIY BP devices I've built...
home.comcast.net/~thomasw_2/CheapskateBP1.html

HT-Guide member GlennB mounted one of the "Q" trannys in a rack mount chassis. He added an additional smaller tranny to isolate devices having digital power supplies from those with standard analog supplies...

[jimcant]

Thomas W,

I would like to thank you, for widening the scope of topics covered here, and sharing your knowledge of them with us

No doubt they are discussed on other sites, but I do not have the the time or enthusiasm to stray very far from here, and appreciate that you have taken the time to share them with your faithful flock, of which I am one.

Would this balanced power supply be available in a 240 Volt version, and be beneficial in my situation?

My power supply is a little unusual.
I am at the end of a 33KV, 3 phase supply line that travels about 15 miles overland to where I live.
There is a pump station about 200 yards from my shed, with about 400 KW of electric motors in it running for most of the summer.

I have no idea whether this has any effect on my audio equipment. It is just something I have pondered, given the lengths that some go to, to filter their power supplies.

Thanks,
Jim.

[ThomasW]

Hi,

The motors in the pumping station are no doubt having an impact.

My experience is that balanced power provides benefits in virtually any A/V situation. The problem you'll run into is finding affordable transformers. I don't know what products are available in Oz. Equi=Tech will custom build transformers for any need, but the cost of having one built and shipped to you would be prohibitive.

Although not a 'balanced' power supply, you might find used medical isolation transformers at Oz auction sites. These combined with surge protection, ECM, EMI/RFI filters are always helpful

[jimcant]

Thomas,

Thanks for that

I did a bit of Googling and found this,


www.tortech.com.au/balanced_studio_power_supply.html

It sounds a lot like what you have described.
No idea of cost, but I might make some enquiries.

Cheers,
Jim.

Wow, I just managed to post my first link, and it actually worked.
Watch out ;D

[Eskimo]

Would you say there's still a big enough benefit to building one of these that could supply ONLY my pre-pro and PS3 (aka blu-ray player)?
Adding the projector (350watt draw) would exceed the 800VA limit.

I did find a 1000VA unit that would work and would allow me to include my projector.. Y236959 -apparently, Avel-lindberg sells direct, at least they did a few years ago - a guy on the DIY audio board mentioned picking up this transformer for about $69..

This looks like it could be an enjoyable snowy-day project..

By the way.. does running my gear at 240V accomplish the same thing (with the exception of some of the filtering, I'd imagine), since we're going from 120V/0 to 120V+/-120V to get the 240? All my gear (except the dang EP2500) is dual voltage.

[jimcant]

I contacted tortech and was quoted $1200 AUD for a 2kVA unit, and around $900 for a 1kVA.

I have no idea whether this is reasonable or not.

I have read all of your links, Thomas, and am somewhat tempted to try a DIY version like yours. Very nice work BTW

Cheers,
Jim.

[ThomasW]

Jan 12, 2009 21:06:27 GMT -7 jimcant said:

I contacted tortech and was quoted $1200 AUD for a 2kVA unit, and around $900 for a 1kVA.

I have no idea whether this is reasonable or not..

Can't say if it's reasonable for you. The Equi=tech trannys I buy are $600 USD for 1.5kVA but that's a raw tranny in a generic electrical utility box. These are typically sold with a fancy machined alu chassis with RFI/EMI and surge filtration for $2000 or more USD .

I think it might be a good idea to just keep looking and perhaps you'll run across a surplus or used unit.

[afwjam]

I am Guessing that my power-center is much to light to have one of these in it. Guess I need one, huh, Thomas?

[ThomasW]

If you're referring to a 3500, it has EMI/RFI filtration and surge protection.

Need one? Well if you have a spare $600 + shipping these are a nice addition to any A/V system.... IMO

The Power Center would plug into the "Q" tranny.

[Eskimo]

Got a reply on the 1KVA unit.

Hi Rich:

Type: Y236950

1 pc: $131.03

Delivery: Stock

Shipping: $13.90, via USPS, or $17.50 via UPS (I had given my zip)

MasterCard and Visa accepted.

Please call 800-979-1022, x 1, or fax [phone] to order.

We look forward to meeting your transformer needs.

Melanie Roman
Avel Lindberg Inc.
47 South End Plaza
New Milford, CT 06482
860-355-4711, ext 41
Fax: [phone]

[ThomasW]

Jan 13, 2009 13:32:38 GMT -7 Eskimo said:

Got a reply on the 1KVA unit.

That's fine for front end gear.

Don't plan on plugging a receiver or power amp into it because they have way too much current draw.

Parts Express stocks the 800VA tranny (p/n 122-720) for $105

If you want a more manly unit Plitron sells a 2kVa unit.
www.plitron.com/shopping/shopexd.asp?id=332

I have one of these and I need to get my butt in gear and finish up the project.



Here's a comparison between the Equi=tech "Q" tranny verses the Plitron.

[Eskimo]

The 1KVA would allow me to connect the pre-amp, PS3 (blu-ray player), and projector.

The 800VA would force me to leave out either the projector (350watt draw) or the PS3 (200 watt draw).

By the way.. Does a US-220V circuit accomplish something similar, albeit without some of the filtering given by the EMC filters and capacitors? I guess it does, since we get the 220v by using both legs of the breaker box, but I'm relying on the transformer out in the big green box outside to provide a good clean balanced power.

[ThomasW]

Jan 14, 2009 12:39:14 GMT -7 Eskimo said:

By the way.. Does a US-220V circuit accomplish something similar, albeit without some of the filtering given by the EMC filters and capacitors? I guess it does, since we get the 220v by using both legs of the breaker box, but I'm relying on the transformer out in the big green box outside to provide a good clean balanced power.

Balancing the power requires 1/2 the voltage running on the neutral and doing that takes a special transformer.

Given the $100+ difference between the 1kVA Avel Lindberg and the 2kVA Plitron, understand you can plug BIG amps or a receiver into the Plitron.

[Eskimo]

Thanks for the info!

[Grazer]

Hi Thomas,
I'm interested in the concept of a balance supply, I made the same enqiry as Jim to Tortech in OZ and got a quote of $1200 also. www.tortech.com.au/balanced_studio_power_supply.html
I'm just concerned that if I can't plug all the gear into it the one unit, RCA earthing might be an issue between components.

I'd be keen to know if you think this the improvement is worth pursuing ? is it enough to justify the expense or should I spend another $K on a better amp and just run a dedicated power point with a dedicated earth?

Dave

[Rhue]

Interesting system for troubled power supply.

Did someone perform double blind test ( ABX ) with this balanced power?

[ThomasW]

Jan 15, 2009 2:57:28 GMT -7 Grazer said:

Hi Thomas,
I'm interested in the concept of a balance supply, I made the same enqiry as Jim to Tortech in OZ and got a quote of $1200 also. www.tortech.com.au/balanced_studio_power_supply.html
I'm just concerned that if I can't plug all the gear into it the one unit, RCA earthing might be an issue between components.

I'd be keen to know if you think this the improvement is worth pursuing ? is it enough to justify the expense or should I spend another $K on a better amp and just run a dedicated power point with a dedicated earth?

My quad-amped system uses multiple high-end amps (several are Ayre K5-xe), they run with dedicated lines and balance power made an improvement when it was added. That said, get dedicated line or lines before investing in anything else

Jan 15, 2009 4:08:42 GMT -7 Rhue said:

Interesting system for troubled power supply.

Balance power isn't a 'fix' for a anything...

Did someone perform double blind test ( ABX ) with this balanced power?

Me? A blind test? Certainly not.

In my system the improvement was so blatantly obvious even my non-audiophile girlfriend commented about it. One of the things improved is the clarity and color saturation of my front projection video system.

I'm not selling anything here. If people have doubts as to the benefits they should arrange for an in home demonstration, or purchase from someone offering a 30 day money back guarantee.

[Rhue]

Me? A blind test? Certainly not.

Belief and illusions are not the truth. Cult or not, a test ABX is the best way to prove something existing.

[afwjam]

I'll take Thomas's word on this one, though I don't have the money to fallow at the moment.

[ThomasW]

Jan 16, 2009 1:47:36 GMT -7 Rhue said:

Belief and illusions are not the truth. Cult or not, a test ABX is the best way to prove something existing.

Obviously this is your issue, if it's something really important start a thread about it as opposed to hijacking this one....