Balanced Power Project: A few questions

[george_k]

I'm starting a DIY Balanced Power project built around a Plitron 7397-B2-00, low noise with NBT (see http://www.plitron.com/PDF/nbt.pdf)

To this I'm planning to add an oem blackbox surge suppressor from zero surge (see http://www.zerosurge.com/PDF/OE4M.pdf)

My two questions are:

1. Where would I wire in the zero surge unit, on the primary side (hot side) of the transformer or the secondary side?

2. I noticed that this particular transformer did not have an electrostatic screen like thie one indicated here www.plitron.com/PDF/857502.pdf from what I understood this is required to comply with the electrical code am I right? is there a way to get around this or would I have to contact the manufacturer and arrange for a custom design (if possible)?

PS: I can't think of anything else that might be required in the diagram I've included, the EMI/RFI is supposedly taken care of within this particular model transformer.

Thanks for reading,

George

[ThomasW]

Yep that's the Plitron tranny most people use.

I'd put the Zero surge before the BP unit.

I use EMI/RFI filters with all my BP trannies

If you're willing to wait a long time Plitron will custom wind anything you want, for a price.

Personally I think the Equi=tech "Q" trannies on a box are a far better device. They're $400US and weigh double the weight of the Plitron

[george_k]

Thomas,

The Equi=tech Q's would be far to expensive by the time they made their way to me (Montreal, Canada).

What EMI/RFI filters do you use in particular for your units?

Thanks!

[ThomasW]

I've built 4 different DIY BP units ( a search of this forum will bring up the theads.)

I used EMI/RFI filters from Schurter and Corcom

[chasw98]

Thomas:
What were the benefits of building a Balanced Power unit? Did you hear any significant differences or were they subtle differences? Electrically I understand the concept of 2 60 volt legs vs a neutral and 120 volt leg. Would you liken this to the balanced vs unbalanced of pro and consumer devices? Thanks for your thoughts.

Chuck

Never mind. I searched and found all sorts of info from you. No need to repeat yourself. Thanks!

[ThomasW]

Just so everyone understands I have two big systems in the house. One is a tri-amped 3-way, the other a quad-amped 4-way. Every piece of gear in both systems is run on balanced power

[JoshK]

I count myself as a born again believer in power conditioning. I use to think that such people were a little out there, but the Felicia project along with experiments with a number of other balanced and isolation devices has made me see the error of my ways.

There is those that believe that a properly designed PSU will mitigate the advantages of a 'power conditioner' but I have not found that to be true. It merely lessens the effect same with the difference a PC makes with really bad power versus ok power from the wall (imo noone has really good power in the US).

Balanced power does a lot to reduce common mode noise, but nothing for differential noise. Many commercial BP product also use accross the line caps to add some differential filtering as well. The Audience Adept takes quite a bit different approach and does a fairly good job with differential noise IME. The Felicia project that Paul and I started takes a mix of both approaches for smaller power applications and we think it sounds pretty good.

I say add as much as is reasonable. Its like the motto of this forum, more is better and too much is never enough!

[george_k]

Thomas,

I took your input and completed the diagram. I still have to inquire about the electrostatic screen though.

[ThomasW]

On some of my designs I've put a single large EMI/RFI filter on the input, then individual smaller filters on the outputs. That helps with the problems associated with digital power supplies dumping noise backward into the AC line.

[george_k]

Good point, an additional filter between the voltage surpressor and toroid and a 25-30A fuse on the input side of the entire system.

[chasw98]

Thomas
I have taken a 24 hour crash course in BP and have read a bunch of reviews from paid and not paid reviewers, read through a lot of threads here. They have all gushed over the immediate sonic and visual benefits of BP. It appears that for $400.00 for an Equi-tech blem transformer and $100.00 in parts a pretty stout BP rig can be built. This sounds (according to reviewers) like one of the best cheapest upgrades to a system that will bring immediate audible benefits. What is your personal experience with the benefits of BP that you can hear? Thanks for your opinion.

[ThomasW]

It lowers the audio noise floor across the board. Video quality improves as well.

People talk about how much better their systems sounds in the middle of the night, well BP provides that improvement 24/7

The $400 "Q" tranny in a box is a steal. It's the same tranny used in their $2500 standalone unit.

For those that frequent AVS, Jeff (the bland?) powers his system with 4 of the "Q" in a box trannies

[george_k]

Would there be any reason to have some output with just surge protection and no balanced power and have others with both surge protection and balanced power?

What about idle power draw?

I'm also looking at these filters http://www.cor.com/Series/PowerLine/EMC/

[ThomasW]

I don't see any reason to have unbalanced outputs. If you want that just build a separate device with whatever filters seem reasonable.

Idle draw? Obviously there's some since all the Plitron trannies I have hum, ask Plitron for specifics.

Yep those filters are fine.

[Glen B]

Good point, an additional filter between the voltage surpressor and toroid and a 25-30A fuse on the input side of the entire system.

I would use a 20A fuse/breaker.

[Glen B]

I still have to inquire about the electrostatic screen though.

The absence of an electrostatic screen is not a code issue. The screen's function is to help reduce the passage of noise between the primary and secondary windings. In use, the screen is grounded. The only downside to using a transformer not specifically designed for balanced power is that its level of noise reduction may not be as good as one with a screen.

[george_k]

Glen B,

I wanted it to be rated at 2,000 watts and have an electrostatic shield for the input and output ground connections (electrical code requires that the ground be passed through from input to output for safety reasons). This electrostatic ground shield is situated between the primary and secondary windings.

I got that from the secrets site http://www.hometheaterhifi.com/volum...er-8-2003.html

[JoshK]

You don't have to have a screen to be in code, in this case you'd be using something more like an isolation transformer and you have to ground the outlet's ground to earth ground and you are still passing the ground from "input" to "output". However, my experience with testing different tx's for our Felicia project (smaller tx's) was that ones with screens were preferrable and grounding the screen as opposed to floating it (not in code) was preferrable.

Occam (Paul) and I did spend a few weekends testing and listening to different combos. It got tedious after a while but was very enlightening.

[Glen B]

Glen B,



I got that from the secrets site http://www.hometheaterhifi.com/volum...er-8-2003.html

IMHO, the way the sentence you are referring to in the Secrets article is written, it is easy to misinterpret what is required. As Josh said, you need to pass the center-tap of the transformer secondary to the incoming ground. If there is a screen, it also needs to be grounded that way.

[george_k]

Glen B,

That is what I'll do, I've sent out an e-mail to see if I can get that particular transformer rewound with a screen.

[Occam]

Glen B,

That is what I'll do, I've sent out an e-mail to see if I can get that particular transformer rewound with a screen.

George,

The Plitron NBT technology (US Pat#6,087,822) has much to offer for split rail power supplies in dealing with differential noise, when it comes to situations where the draws on each rail may be different.
But specifically in balanced power applications (technical power), it is far more effective to simply use Y caps to deal with differential noise. As differential noise becomes balanced differential noise at the secondary, noise shunted by equal caps from from the antiphase legs to ground 'cancel', like the reactive leakage currents do in the fed components.

Regardless of the mechanism you might add to deal with differential noise via added capacitors, whether via Y caps, NBT (basically an X cap), or additional filters, with toroidal transformers, a grounded shield between primary and secondary is the first line of defense, tremendously adding to its power conditioning efficacy. As ThomasW mentioned, the Equitech 'blems' are a tremendous bargain.

Regards,
Paul

[brucemck2]

Is there a "summary document" somewhere that I could hand to a competent electrician to describe an install of balanced power, filters, etc?

I can not run new wires into the room, but, can "isolate" the room as it's on two dedicated circuits inside the panel.

I'm not competent to do the work myself, but from thread can not identify the "spec" to be handing off.

[ThomasW]

I don't think there are tech documents about this. However any electrician would know how to wire up the Equi=tech, Q-transformers in a box, since the 'box' is a generic subpanel designed to fit between 16"OC studs (obviously they can be surface mounted if necessary). There are wiring diagrams glued to the inside of the panel



Hard wiring EMI/RFI filters into the box won't meet code. So those should be in a separate portable device if you're going to get this inspected.

If you're not going to get the installation inspected there are wiring diagrams printed directly on the EMI/RFI filters