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Balanced Power!

post #1 of 67
2/24/08 at 7:59am
Thread Starter 
Hey guys,

After seeing a few balanced power supplies and a balanced power supply build, I'm interested. Unfortunately with the head-fi outage a few months back, all of the pictures went down so I can't find the schematics.

Either way, I'm looking for ideas, comments, impressions, pretty much any useful info on balanced power supplies I can find. I've seen a couple of DIY line filters and A LOT of arguments against such things, but most of them end at "look at how much bad power lines go to your house and inside your house, how can it make a difference". My opinion is that if I can forget about all the crappy wires going to the wall socket and focus on the OK level power cord going to my balanced power supply and then it gets serious where I use high quality cables (12AWG SPC in Tefon) to a nice quality 2x 60V transformer and exiting to nice quality power sockets and nice cables following that to any of my equipment.

That way I can skip through all the crap of "power cables don't make a difference when compared to the power cables used everywhere else".

If anybody has some suggestions, comments, or as I said before any useful info about a balanced power supply build or even general balanced power information which might be helpful in this build, I would love to hear (read) it.

Please do not post any negative (or counterproductive) comments about power supplies, filters or power cabling, THEY DO NOT CONTRIBUTE IN A PRODUCTIVE MANNER HERE!

Thanks to the people who can contribute, much appreciated, I'm somewhat new to the whole balanced power idea. I have read a lot about balanced vs isolated power supplies, and after the research that I've done, I'm only interested in Balanced Power.

Thanks!
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post #2 of 67
2/24/08 at 11:09am
This seems like a pretty comprehensive discussion. I was inspired to look into this too but haven't done much with it yet.

The third post has some other reference links.
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post #3 of 67
2/24/08 at 1:15pm
Wow, it's been a while since I visited triode systems web page , I built the "easy mains filter" a few years ago and at the time I had convinced myself that it made a difference. It has been part of my system since then. It makes me feel better that it's there and I added varistors into the mix ( and yes I know there has been a lot of criticism about them too ) to keep the equipment safe.

I had picked up a massive autotransformer but had to dump it when I moved , this may be something to look into - you can find highly regulated autotransformers at medical surplus suppliers.

The only link I have for balanced AC is Batman's version.

Good luck with this..dB
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post #4 of 67
2/24/08 at 4:29pm
Quote:
except I skipped the chokes because I am also looking to use this for my speaker amp which I've read does not benefit from having a choke inline and might degrade the signal.
you ommited the inductors? then this is no longer a filter.
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post #5 of 67
2/24/08 at 4:42pm
Quote:
Originally Posted by kipman725 View Post
you ommited the inductors? then this is no longer a filter.
The OP is very specific about such posts... There's no obvious contribution in your post...

That said,
da_burl, some of the links in that thread you pointed no longer work because of the outage of a few weeks ago.


Fallenangel, could you provide links to what you've read regarding power filtering and balanced power? I would like to do further reading on this.

Thanks in advance.
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post #6 of 67
2/25/08 at 1:44am
Quote:
Originally Posted by kipman725 View Post
you ommited the inductors? then this is no longer a filter.
it WILL filter ANY dc component off of the power line. it will also filter out common mode noise. depending how the transformer is designed (with deliberately limited bandwidth...) you can get QUITE a bit of filtering out of JUST a transformer.
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post #7 of 67
2/25/08 at 4:20pm
Quote:
Originally Posted by nikongod View Post
it WILL filter ANY dc component off of the power line. it will also filter out common mode noise. depending how the transformer is designed (with deliberately limited bandwidth...) you can get QUITE a bit of filtering out of JUST a transformer.
ah yes but then why are you bothering with an pre rectification filter in the first place as you will have the same order of the filter if you just rectified and used the rail capacitors. The inductors increase the order of the filter greatly increasing the attenuation at the frequancys of intererest. How is my post not usefull?

also any dc component is already filtered by the the transformer.
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post #8 of 67
2/25/08 at 10:56pm
Quote:
Originally Posted by kipman725 View Post
ah yes but then why are you bothering with an pre rectification filter in the first place as you will have the same order of the filter if you just rectified and used the rail capacitors. The inductors increase the order of the filter greatly increasing the attenuation at the frequancys of intererest. How is my post not usefull?

also any dc component is already filtered by the the transformer.
this is not a pre-rectification filter, but a big isolation transformer (wired up with a balanced output)between the wall and "the device." totally different topic.

regarding the DC component being filtered out by the transformer in "the device" (dac, amp, phono stage, etc, etc) that is correct until the transformer saturates, starts leaking EMF, and generating excess heat. for quite a few things (many if not most comercial amps come to mind) transformers are already run AT rated load with little overhead, in tight cases with too little venting...
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post #9 of 67
2/25/08 at 11:22pm
Thread Starter 
Nice discussion, very interesting so far.

Note to self : overspec transformers quite a bit

Interesting articles that I've enjoyed: Jon_Risch's Web Page, Index - nice info on balanced power and mains filters.
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post #10 of 67
2/25/08 at 11:57pm
I have used a 1000va transformer for my audio gear to provide balanced power. I did not notice a big differance, BUT, I am lucky to have very clean juice at home. I can hit the substation with a rock from my front door that my power feed comes from. (my line voltage averages 122-125 volts and is rock solid also. No brown outs!)

Check out Equitech's web site for good info on balanced power-

FAQ's About Balanced Power
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post #11 of 67
2/26/08 at 2:04am
http://www.jensen-transformers.com/a...%20seminar.pdf

section 5.4, ~p39 discusses "balanced power"
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post #12 of 67
11/11/08 at 12:36am
Thread Starter 
Drool.... Surplus Transformer
Are you thinking what I'm thinking
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post #13 of 67
11/11/08 at 12:53am
Quote:
Originally Posted by FallenAngel View Post
Drool.... Surplus Transformer
Are you thinking what I'm thinking
Better be seated when the price quote comes in......similar in idea to Richard Grey Pole Pig. A big ass auto former will do the trick. My power issues are with tube gear needing 115V when my line level is always 127....I too can hit the sub station with rock from my front door.

Going balanced using J Risch's design is perfectly good and just as good as the multi K name brand units IMO.

I have dedicated lines, line conditioners, nice mains cables....they all made a nice difference to the overall black level. What I need is an autoformer to drop my level from127 to 117 or thereabouts so my tube gear can run closer to spec on the heaters. Damned power around here is too good

The nth degree I suppose would be balanced and completely isolated, then regenerated to a dead nuts perfect 115/120V at 60hz using one of the many uber expensive regenerators out there. PS Audio, Furman Elite Signature, Richard Grey etc...

I think FA, going balanced is a good idea. Go for it.

Peete.
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post #14 of 67
8/24/09 at 1:27am
Thread Starter 
About a year late but I've pulled the trigger on that MONSTER 2.4KVA Plitron. Balanced power supply here I come. I'll make some panels using FPE and stuff it into a big 16" x 12" Par-Metal 20-series box.

Still a few things outstanding:
1) Any recommendations on soft-start circuits?
2) Any recommendations on outlets?
3) Any recommendations on how to wire input (hardwire vs IEC)?

I'm also still undecided on surge protectors and filtering though I'm thinking of one of the 20A Qualtek filters from mouser (Catalog page 1125).

Thanks in advance.
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post #15 of 67
8/24/09 at 1:49am
Hubbell make good medical grade sockets

I googled them and found VT4C stock them as well as some other looking ones for a lot less money.



There are a few soft start circuits about, I am sure others have them at their fingertips.

As for wiring , I would opt for iec for convenience but hard wiring makes more sense if it is a fixed unit.

..dB
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