DIY Balanced AC Power Conditioner

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Originally Posted by NV001

Great work, Glen. I just came across your posting - the project is impressive. Tried to access the schematic, but the link seems to be broken. Could you repost? Thanks!

J

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Here is a basic schematic showing a single isolation transformer. Across the primary is an optional varistor for surge protection (Digi-Key part # P7324-ND / Panasonic part # ERZ-V20R241) and 0.47uf caps across the primary and secondary. I use 600V rated Auricaps. X rated caps are normally used in applications across the AC mains. Ther has been dbate about the use of Auricaps. The manufacturer, Audience lists AC line use in their application notes. I have been using them for the past 5 years without incident.

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Originally Posted by Glen B

Here is a basic schematic showing a single isolation transformer. Across the primary is an optional varistor for surge protection (Digi-Key part # P7324-ND / Panasonic part # ERZ-V20R241) and 0.47uf caps across the primary and secondary. I use 600V rated Auricaps. X rated caps are normally used in applications across the AC mains. Ther has been dbate about the use of Auricaps. The manufacturer, Audience lists AC line use in their application notes. I have been using them for the past 5 years without incident.

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Thanks a lot, Glen.

Sorry 'bout my ignorance, but I'm curious. :) In general, are there component designs that don't tolerate balance power input?

Regarding the schematic ...

• Are the 60V output taps opposite phase?
• Are the caps both across these 60 taps and the input 120V/0V leads the 0.47 uF caps you refer to.

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Originally Posted by Feanor

In general, are there component designs that don't tolerate balance power input?

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No specific designs -- as with all other types of power conditioning devices, once in a while you will find components that don't work well sonically with balanced power.

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Are the 60V output taps opposite phase?

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Yes, just like household 240V (120V-0-120V).

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Are the caps both across these 60 taps and the input 120V/0V leads the 0.47 uF caps you refer to.

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Yes.

Thank you for sharing this with us Glen

Could you send me a pm with few answers please?

How important are the filters you used (corcoms ) ?

Do I need a circuit breaker ?

Is it better to use multiple transf.?

thank you for your help

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Originally Posted by twekr

How important are the filters you used (corcoms ) ?

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The RFI/EMI filters provide some increased noise reduction, and inter-component isolation when used on the secondary side, though they are not an absolute necessity. As a downside, during my extensive listening sessions, I found the filters to cause a loss of detail and transparency. I stopped using them as you will see in my updated pics. I tried both Qualtek and Corcom and the results were the same with both. You may find otherwise. Listen for yourself.

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Do I need a circuit breaker ?

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Yes, circuit breaker or time delay fuse (type MDL) rated according to the size of transformer used.

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Is it better to use multiple transf.?

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I find multiple transformers preferable to a single transformer with EMI/RFI filters as mentioned above. The multiple transformers IMO provide maximum component isolation without the sonic downside, though at much greater cost. Good transformers are not cheap.

Thank you again,

Do you think a 20 A breaker is okay for a 2000VA unit ?

I am going to try the silica sand to dampen the vibration and noise of the transformer .

Therefore the filters are not a must correct Glen ?

Should I still use the .47 uF caps on the prim and second

Do we use a resistor across to drain the caps ?

Can we use Solen caps or any hi voltage NP caps instead ?

I noticed that Audience units sell upgraded Teflon packages for an extra $1000 on their units
Do you think it will give a sonic difference ?

Cheers

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Originally Posted by twekr

Do you think a 20A breaker is okay for a 2000VA unit ?

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Yes, I recommend a Potter & Brumfield 20A hydraulic-magnetic breaker, available from.Digi-Key, their part # PB593-ND.

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I am going to try the silica sand to dampen the vibration and noise of the transformer .

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May not be good idea. How do you plan to accomplish this ? If you pack the transformer in any material other than potting compound, you may increase it operating temperature. A good quality transformer should not be noisy in the first place. To minimize noise transfer to the chassis, try extra padding underneath. I also recommend sound dampening material on all inside surfaces of the chassis. Make sure the material has flame retardant properties.

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Therefore the filters are not a must correct Glen ?

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They're optional. YMMV. Experiment.

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Should I still use the .47 uF caps on the prim and second.

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Also optional. Experiment.

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Do we use a resistor across to drain the caps ?

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No. Why ?

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Can we use Solen caps or any hi voltage NP caps instead ?

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There is an issue of Auricaps not being UL listed for use across the AC line, although the manufacturer "suggests" its okay. Same issue with Solen and other "audiophile" brands. I've been using Auricaps for over 5 years without incident. Wima X- rated film caps will work fine in this application.

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I noticed that Audience units sell upgraded Teflon packages for an extra $1000 on their units
Do you think it will give a sonic difference ?

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I have not tried the teflon caps and can't comment. I'm sure they're fine caps but I would rather spend $1,000 to make improvements elsewhere, like in better outlets.

I'm thinking about buying one of these and having it installed

http://brickwall.thomasnet.com/item/...p20?&forward=1

Thanks for sharing, I have been looking to something like that for a while. The only concern I have is working with main voltage :)

Hi,

I know this thread is a little stale but I thought I would take a shot...

I am about to build a balanced power supply. Basically it is only going to power digital stuff like my preamp, dvd/blu ray etc.... plus my TV (which I guess is analog). My amplifer will not be plugged into this.

My plan is use the EMI/RF filter designed by Jon Risch however I cannot not seem to find a good answer as to where to place the filter. Either before ON the primary or after on the secondary.

From the article at Equitech, having filters on the seconday seems to be "required" as it provides a pathway for reactive currents to flow to ground.
http://www.equitech.com/articles/origin.html (see figure 2)

I read other places to put it before - on the primary and just wire the secondary taps "directly" to the outlets.

Then I read Jon Risch saying do a hybrid.... which puts the inductors and 1 bypass (across both 60 hot wires). http://db.audioasylum.com/cgi/m.mpl?...rmer+Jon+Risch

I have uploaded my schematic drawing of the Jon Risch filter that is on the primary.
http://forums.audioreview.com/attach...1&d=1268107554

Just wondering if anyone could offer any clarification on this. The equitech diagram (figure 2) makes the most sense to me as it is providing a pathway for reactive (noise) currents to ground.


Thanks!

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Originally Posted by bengel

Hi,

I know this thread is a little stale but I thought I would take a shot...

I am about to build a balanced power supply. Basically it is only going to power digital stuff like my preamp, dvd/blu ray etc.... plus my TV (which I guess is analog). My amplifer will not be plugged into this.

My plan is use the EMI/RF filter designed by Jon Risch however I cannot not seem to find a good answer as to where to place the filter. Either before ON the primary or after on the secondary.

From the article at Equitech, having filters on the seconday seems to be "required" as it provides a pathway for reactive currents to flow to ground.
http://www.equitech.com/articles/origin.html (see figure 2)

I read other places to put it before - on the primary and just wire the secondary taps "directly" to the outlets.

Then I read Jon Risch saying do a hybrid.... which puts the inductors and 1 bypass (across both 60 hot wires). http://db.audioasylum.com/cgi/m.mpl?...rmer+Jon+Risch

I have uploaded my schematic drawing of the Jon Risch filter that is on the primary.
http://forums.audioreview.com/attach...1&d=1268107554

Just wondering if anyone could offer any clarification on this. The equitech diagram (figure 2) makes the most sense to me as it is providing a pathway for reactive (noise) currents to ground.

Thanks!

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Welcome to AR Forums, Bengel.

Sorry, I don't think I answer your question, (but see below). I think you might do better with such questions over at DIYaudio where there are more technophiles than around here.

Maybe my eyes (or brain) misleads me but in JR's Audio Asylum reference it almost looks like the PS there is not a balanced supply: the outputs are labeled "H" and "N", not "+" and "-" as you would expect from a balanced supply -- of course it might just be a typo. However that being the case, I wouldn't risk putting a capacitor across the + and - taps on balanced supply.

Thanks for the schematic you supplied which is very interesting. It's tempting to me to consider such a project in the future.

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Originally Posted by bengel

Hi,

I know this thread is a little stale but I thought I would take a shot...

I am about to build a balanced power supply. Basically it is only going to power digital stuff like my preamp, dvd/blu ray etc.... plus my TV (which I guess is analog). My amplifer will not be plugged into this.

My plan is use the EMI/RF filter designed by Jon Risch however I cannot not seem to find a good answer as to where to place the filter. Either before ON the primary or after on the secondary.

From the article at Equitech, having filters on the seconday seems to be "required" as it provides a pathway for reactive currents to flow to ground.
http://www.equitech.com/articles/origin.html (see figure 2)

I read other places to put it before - on the primary and just wire the secondary taps "directly" to the outlets.

Then I read Jon Risch saying do a hybrid.... which puts the inductors and 1 bypass (across both 60 hot wires). http://db.audioasylum.com/cgi/m.mpl?...rmer+Jon+Risch

I have uploaded my schematic drawing of the Jon Risch filter that is on the primary.
http://forums.audioreview.com/attach...1&d=1268107554

Just wondering if anyone could offer any clarification on this. The equitech diagram (figure 2) makes the most sense to me as it is providing a pathway for reactive (noise) currents to ground.


Thanks!

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The Equi=Tech article is not saying that filters on the secondary are "required". The discussion linked to is only discussing reactive currents and using capacitors to show the relationship of those currents. Caps on the secondary are useful as simple differential filters, and the simplest method of decoupling outlets, but are not an absolute necessity.

A single noise filter such as the Jon Risch is most useful ahead of the balanced isolation transformer, as Jon has it in the PDF schematic above. You should also make sure to isolate your preamp AC from your digital equipment. Caps across the outlets IMO are a minimum. Separate Jon Risch filters on the secondary, feeding the preamp and digital components is second best. The ultimate IMO would be separate isolation transformers for your preamp and digital/TV. Go back and re-read Jon's responses on AA where he recommends that "in theory, using isolated filters on each separate digital component would provide some benefit".

As an alternative to using Jon Risch filters on the secondary, you could experiment with packaged EMI/RFI filters like Corcoms. Just note that I've done extensive experimentation with various Corcom and Qualtek filters and to my ears, they had a noticeable negative effect on the sound when switched into the electrical path. They should be fine with TV. YMMV.

Glen

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Originally Posted by Glen B

The Equi=Tech article is not saying that filters on the secondary are "required". The discussion linked to is only discussing reactive currents and using capacitors to show the relationship of those currents. Caps on the secondary are useful as simple differential filters, and the simplest method of decoupling outlets, but are not an absolute necessity.

A single noise filter such as the Jon Risch is most useful ahead of the balanced isolation transformer, as Jon has it in the PDF schematic above. You should also make sure to isolate your preamp AC from your digital equipment. Caps across the outlets IMO are a minimum. Separate Jon Risch filters on the secondary, feeding the preamp and digital components is second best. The ultimate IMO would be separate isolation transformers for your preamp and digital/TV. Go back and re-read Jon's responses on AA where he recommends that "in theory, using isolated filters on each separate digital component would provide some benefit".

As an alternative to using Jon Risch filters on the secondary, you could experiment with packaged EMI/RFI filters like Corcoms. Just note that I've done extensive experimentation with various Corcom and Qualtek filters and to my ears, they had a noticeable negative effect on the sound when switched into the electrical path. They should be fine with TV. YMMV.

Glen

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So you run the caps straight across both hot legs of the outlet? Or should you run them across each hot leg to ground (i.e. 2 caps per plug). Size matter? Conventional wisdom, bigger capacitance is better, i.e. >2.5 uF?

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Originally Posted by bengel

So you run the caps straight across both hot legs of the outlet? Or should you run them across each hot leg to ground (i.e. 2 caps per plug). Size matter? Conventional wisdom, bigger capacitance is better, i.e. >2.5 uF?

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Connect the caps across the two hot poles of the outlet. No cap to ground. Caps should be around .47uf 250V X-2 rated (for across the AC line usage). Wima .33uf film 250V X-2 rated noise supression caps from Mouser will work fine. You can use one or two pieces across each outlet. The x-rated caps fail open, thus preventing a fire. You don't want to use caps that fail as a short. Too large caps (total value greatar than 1uf) are not necessary. All you will have is unnecessary leakage across the poles. I've been using .47uf 600V Auricaps, for the past 5+ years without incident. These are not marked as x-rated, although the manufacturer's usage notes say they fail open and are safe for AC noise suppression use.

Wima caps: http://www.mouser.com/Search/Product...hsQpAmomCk0%3d

Thanks for the insight/advice....

I went with these caps as they were cheaper and easier to mount across the outlets. They are also X2 rated...

http://mouser.com/Search/ProductDeta...5-F17734472000

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Originally Posted by bengel

Thanks for the insight/advice....

I went with these caps as they were cheaper and easier to mount across the outlets. They are also X2 rated...

http://mouser.com/Search/ProductDeta...5-F17734472000

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Those should be fine. I only mentioned the Wimas because they came highly recommended.

Glen,

Just stumbled across your posts on your DIY power conditioner. I have several transformers (700VA) and left over Auricaps. You have inspired me to take a stab at building my own.

I also have a PS Audio Soloist and thinking about using it to front end the power conditioner. It should help with filtration and surge suppression.

One question on your build. I noticed only one cap on the primary side of the larger (2KVA) transformer. Did you install caps (primary side) on the smaller transformers.

Your build looks very nice.

Regards,

Marty

Marty, a single 1uf 600V cap is across the incoming AC, so it benefits all three transformers.

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Originally Posted by Glen B

Marty, a single 1uf 600V cap is across the incoming AC, so it benefits all three transformers.

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Thx Glen.

I figured you went with a larger value.

Marty

Hi Glenn!

Is there a difference in the sonic result between the standard industrial toroid and the model made by equitech?

Thanks: David

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Originally Posted by zycomatique

Hi Glenn!

Is there a difference in the sonic result between the standard industrial toroid and the model made by equitech?

Thanks: David

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I'll leave the final answer to Glenn - but, I would suggest probably not.

What exactly do you mean by "industrial toroid" ? Any center-tapped transformer, whether E-I type or toroid, that outputs 60V-0-60V (120V-0-120V in countries that use 240V) can be effectively used as a balanced isolation transformer (poor man's isolation tranny). However, its degree of common-mode noise reduction is likely to not be as great as that of a true balanced isolation transformer. In fact, Parts Express sells an Avel-Lindberg toroid rated at 800VA that outputs 60V-0-60V, and can be used as a poor man's balanced power supply for low-powered amps and sources (hint).

Transformers from companies like Equi=Tech, Plitron and Toroid Corp. of Maryland feature bi-filar windings, and one or two electrostatic shields between the primary and secondary windings, features which may be lacking in other products, and which contribute to increased noise reduction.

Plitron transformers are built around "NBT" (narrow band) and "LONO" (low noise) technology, which further improve performance (read more on the Plitron website). Equi=Tech "Q" type transformers have massive cores, feature low inrush current, and substantial immunity to saturation by power line DC offset, a phenomenon which causes audible mechanical transformer buzz.

Does this translate into a sonic difference? While it is a subjective matter, the greater common mode noise reduction of a true balanced isolation transformer is likely to result in lower system noise floor, and improved sonics. I have tried products from the three above-named manufacturers and found performance differences among them, but that is a discussion probably best left to another thread.

There have been a number of threads on AK and other places on balanced power conditioners, and the benefits they can bring in reducing the noise floor in an A/V setup. So, I started building one and wanted to share some of the details. It is not complete yet, but I will wire it all up hopefully over the next couple of weeks.

What can balanced power do for you? It can be a little, a lot or nothing at all. It depends on how clean the ac input is to begin with. A good isolation transformer can bring much of the same benefits that a balanced power conditioner can bring – namely, reduction in the common mode noise that might be riding on the power lines. But I suppose a balanced power conditioner can be used to extract the last bit of performance from your system.

I've read a Topaz Isolation transformer with a 0.0005 pf rating can have a common mode noise reduction of -146 db. The pf rating seems to determine the noise reduction. How low can you go with common mode noise reduction to reach the noise floor or until it is inaudible to the human ear? Can you get -300 common mode noise reduction? I don't know if it has any differential mode noise reduction. I think what people need to look for is the curve on a graph of the common mode and differential mode noise reduction within a range of frequencies if possible. The problem is I don't know how these frequency ranges affect digital and analog gear separately. Also how do these transformers affect the sine wave?

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Originally Posted by sugarpop233

What can balanced power do for you? It can be a little, a lot or nothing at all. It depends on how clean the ac input is to begin with. A good isolation transformer can bring much of the same benefits that a balanced power conditioner can bring – namely, reduction in the common mode noise that might be riding on the power lines. But I suppose a balanced power conditioner can be used to extract the last bit of performance from your system.

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<O:p</O:p
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I concur.

<O:p</O:p