DIY Balanced Power project

[chasw98]

Thomas:
I don't remember where I read it, but you said that you quit buying EMI/RFI filters from mouser when you found them much cheaper at surplus joints. Where are some of those that you found? Thanks.

[ThomasW]

I bought a lot of the stuff from a place in Boulder CO called J. B. Saunders (they're a B&M operation, only so no online). And unfortunately the last couple times I was up there, they hadn't restocked since I bought them out 2 yrs years ago.

My suggestion is Google for electronics surplus to see what you can find.

Here's one of the online places I found stuff

http://www.electronicsurplus.com/commerce/catalog/spcategory.jsp?category_id=2150

[chasw98]

I know JB Saunders. I bought some Lambda power supplies there many, many years ago. I will start looking. Thanks for the leads.

Chuck

[Brandon B]

Hey Thomas, any clue why the plitron in mine would buzz really loudly when and only when our toaster (as in browner of bread) is in use?

The toaster is plugged into a completely different circuit here, the only common connection is in the main panel. It has an electronic toasting control which I am assuming is similar to the SCR dimmers in cheap halogen lights.

But it seems really odd that running a toaster would make the transformer hum like that. It is nearly silent at all other times, except for a second during inrush if I turn it off and on for some reason.

BB

[ThomasW]

I don't know much about appliances. Is the toaster dumping DC into the line? I don't even know if that's possible.

[chasw98]

Hey Thomas, any clue why the plitron in mine would buzz really loudly when and only when our toaster (as in browner of bread) is in use?

(as in blackener of grain?)

Is the toaster on the same phase as the Plitron? If so, temporarily switch that circuit to the other phase and see if it goes away. I had a similar experience with a fluorescent light on the same phase with a piece of equipment in my system and swapping phases solved the problem.

[chasw98]

Look what showed up at my house today! Now what to do with it :scratchhead:



It is very heavy and huge.......

[ThomasW]

Gee I don't know, how about wiring it up? :B

[Brandon B]

I don't know much about appliances. Is the toaster dumping DC into the line? I don't even know if that's possible.

Don't see how, since all it does is take the AC and use it to heat nickel chrome wire, with a little bit converted to low voltage DC for the electronics.

Maybe it's the reltaively large current drawn by the toaster, but in that case, I would expect to hear it when the AC or the oven was on as well, bu nope.

Not an issue I am looking to solve, as I am not looking for a quiet listening environment when people are toasting breakfast, really just my curiosity.

BB

[Brandon B]

(as in blackener of grain?)

Is the toaster on the same phase as the Plitron? If so, temporarily switch that circuit to the other phase and see if it goes away. I had a similar experience with a fluorescent light on the same phase with a piece of equipment in my system and swapping phases solved the problem.

Phase? Do you mean which leg of the 220 split at the panel?

No real way for me to switch either of them, short of running a big extension cord from somewhere else in the house for the toaster.

It's not putting any noise into my audio chain, just making the transformer hum. weird.

[chasw98]

Sure there is. Just go to the breaker box and find the circuit the toaster is on. Then move the breaker to another slot that is on the different phase than you plugged it out of. But if you don't care about the noise in the morning when making pop tarts, don't bother. We will note it in your membership record of the Hi Fi club that noise is acceptable to you in the morning

[chasw98]

Gee I don't know, how about wiring it up? :B

Like this?

[ThomasW]

Like this?

Yep I think you got it now.

Have anything plugged into it yet?

Oh and BTW, we appreciate the unique decorative touch of the Colo license plate..... :T :B

[chasw98]

Yep I think you got it now.

Have anything plugged into it yet?

Oh and BTW, we appreciate the unique decorative touch of the Colo license plate..... :T :B

Yes, I have an EP2500, Monster HTS3500 feeding pre/pro, DVD, Sat tuner, HD tuner, BFD, front projector, and HTPC. 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!

On the license plate. I have to keep a remembrance of the homeland around.

[ThomasW]

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!

Spread the word brother Chas.... :T

[Brandon B]

Sure there is. Just go to the breaker box and find the circuit the toaster is on. Then move the breaker to another slot that is on the different phase than you plugged it out of. But if you don't care about the noise in the morning when making pop tarts, don't bother. We will note it in your membership record of the Hi Fi club that noise is acceptable to you in the morning

Panel is full, and moving breakers about is a pretty major undertaking, as is even switching wire feeds from one breaker to another.

And how did you know I eat pop tarts? Although it'll be a slow day when you catch me bothering to actually toast them.

It's the wife and her crumpets that are the culprit.

[chasw98]

And how did you know I eat pop tarts? Although it'll be a slow day when you catch me bothering to actually toast them.

It's the wife and her crumpets that are the culprit.

You don't toast them? You probably buy the plain ones instead of the frosted ones. :E
Seriously, take the toaster and plug it into another outlet in your house that is on the other phase. Have your wife make crumpets and see if the problem is still there.

[Brandon B]

Interesting trivia. it used to be that unfrosted ppop tarts had more calories, as they had slightly thicker crust to reach the same overall thickness, and the fat in the crust was more calorific than the sugary frosting. They equalized them about 12 years ago.

For me it's unfrosted if fruit, or frosted if chocolate. Don't like those gross brown sugar cinnamon.

BB

[chasw98]

Interesting trivia. it used to be that unfrosted ppop tarts had more calories, as they had slightly thicker crust to reach the same overall thickness, and the fat in the crust was more calorific than the sugary frosting. They equalized them about 12 years ago.

For me it's unfrosted if fruit, or frosted if chocolate. Don't like those gross brown sugar cinnamon.

BB

You have made me laugh on Monday morning at work! Personally I have not had a pop tart in 20+ years. Although they are in our hurricane kit for emergencies. Right next to the twinkies :T

[bgkorn]

Transformer part number?

Does the 2Q transformer in a box have a unique part numner to identify from a regular 2? Plitron OEM?

[ThomasW]

Don't know you'll need to ask Equi=tech

[here.now]

Was this project ever completed? Tested? Just curious, I've taken an interest in AC power quality for my system. I've found this on Plitrons' site http://www.plitron.com/shopping/shopexd.asp?id=624#

Would this be a formidable component? The price seems right and I dig the fact that it has identical smaller outputs, could this be benificial for low amp source components? Let me know what you think if this is a usable transformer for this application.

-Jeff

[chasw98]

Ths would work for lower current source equipment quite well. If you really want to jazz it up, you can put individual surge and spike protection on each tap of the secondary. According to the spec sheet this transformer will give you 5 outputs at 4 amps each. You can use one for preamp, DVD, Cable or Satellite box, etc. I would hesitate to put any power amplifiers on this though. I would check the current rating on a TV set before asuming that this will handle it.

Chuck

[ThomasW]

I bought 4 of the Equi=Tech trannys so the parts for my Plitron based box are sitting on a shelf in the basement.

If your budget allows I strongly urge you to buy one of the Equi=Tech 'Q' blem trannys since they're once again available. They pretty much define state of the art and unlike the Plitrons, the Equi=Techs I have are dead silent.

[kvardas]

I picked up a "Special" 2Q transformer from Equi=tech and hooked it up last night. I ran a new circuit from my panel to the transformer and then to a single 20A outlet in my house. I then plugged a power strip (with each audio component plugged into the power strip) into the outlet.

It sounds great! My system has been brought to a new level.

[ThomasW]

It sounds great! My system has been brought to a new level.

Oh boy, another convert.... :T :B

[Glen B]

I finally got around to doing another rebuild of my balanced power unit, taking things a step further by adding a third transformer, so that each duplex outlet is now powered by its own dedicated transformer. I used a taller chassis, so that I could side-mount the two smaller transformers.

Other improvements include shortened wiring runs, solid silver and gold plated pure copper wire terminals, WBT crimped copper wire terminations, non-ferrous hardware throughout, surge protection MOV setup that takes only one minute to replace once the top cover is removed, and addition of a power-on LED.

Instead of making my own holes in the rear panel with rotary and nibbler tools, this time around I furnished a cutout drawing with layout and dimensions to chassis manufacturer Par-Metal Corp., and had them punch the holes for a flat $30.00 charge. The result is a cleaner, more "professional" looking rear panel.

The downside is the unit now weighs about 115 lbs.

Current: Image not available

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[Johnloudb]

Really nice work Glenn!! :T Hmmm .... I'm feeling a bit inspired to finish my isolation transformer project now. But, I've got a number of projects on my plate, so realistically I probably put that off for a while yet. What's the power rating of the large transformer and the two smaller ones?

[Glen B]

The ratings are 2kVA/250VA/250VA. The large one is an Equi=Tech Q type. The smaller ones are from Toroid Corporation of Maryland.

[Johnloudb]

My transformer is a Toroid Corp. 1.5kVA sheilded isolation transformer. The first one I wired up had a really loud mechanical hum. I do have an another one like it to try, so I hope that doesn't one hum. I guessing you haven't had any hum problems though?

[wkhanna]

Glen!
That is one great piece of DIY!
Out of curiosity, would you care to divulge your total cost for the BOM?
That is a project I must complete after I get my next set of speakers made.

[mikela]

Will balanced power work for a SMPS powered device?

[Glen B]

My transformer is a Toroid Corp. 1.5kVA sheilded isolation transformer. The first one I wired up had a really loud mechanical hum. I do have an another one like it to try, so I hope that doesn't one hum. I guessing you haven't had any hum problems though?

If you go back to the second link in my post above, you will see a Toroid Corp. 2kVA transformer in my very first balanced power unit. It sang like a bird in the presence of DC on the power line. Whenever the household washing machine was running, it buzzed loudly in time with the agitator. The manufacturer could not provide any solution but to suggest going with a smaller size transformer, which I did not want to do. I've had no problem with the smaller size Toroid Corp. transformers, which are silent.

You could try a DC blocker circuit in series with the hot side of the transformer primary. Classé has employed such circuits in their amps. They use 3,300uf caps but you could go higher (which is what I suggest). I recently built a DC blocker as a favor to a member at another forum and while 3,300 uf worked pretty good, that value did not entirely eliminate the mechanical hum in the transformer of his amp. I had him return the blocker and increased the capacitance value.

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DC blocking circuit:

[Glen B]

Glen!
That is one great piece of DIY!
Out of curiosity, would you care to divulge your total cost for the BOM?
That is a project I must complete after I get my next set of speakers made.

Approximately $1,800, also figuring in hole punching and parts shipping costs. The transformers alone are $1,000.00. The duplexes are Furutech FP-15A silver at $75.00 each. The 20A IEC inlet is a Furutech FI-33 gold at $72.00. The Auricaps used as differential filters are $17.00 each. I plan on eventually upgrading the duplexes to beryllium copper Oyaide R-1s.

Going back to my very first DIY balanced power post 5 years ago, the project was never about cost savings, but rather doing my own take on a cost-no-object unit, based on the best parts and materials I could obtain. I was not satisfied with the parts choices in the manufactured units at the time (and still am to some extent).

Will balanced power work for a SMPS powered device?

I can't think of a reason why it should not work. The device will still be seeing 120V 60Hz.

[Johnloudb]

If you go back to the second link in my post above, you will see a Toroid Corp. 2kVA transformer in my very first balanced power unit. It sang like a bird in the presence of DC on the power line. Whenever the household washing machine was running, it buzzed loudly in time with the agitator. The manufacturer could not provide any solution but to suggest going with a smaller size transformer, which I did not want to do. I've had no problem with the smaller size Toroid Corp. transformers, which are silent.

You could try a DC blocker circuit in series with the hot side of the transformer primary. Classé has employed such circuits in their amps. They use 3,300uf caps but you could go higher (which is what I suggest). I recently built a DC blocker as a favor to a member at another forum and while 3,300 uf worked pretty good, that value did not entirely eliminate the mechanical hum in the transformer of his amp. I had him return the blocker and increased the capacitance value.

Image not available

DC blocking circuit:

Thanks Glenn, I'll give that a try, since it's much cheaper that buying a new transformer. Did the larger value caps solve his transformer hum problem? I might try paralleling 2 or 3 of those caps.

[Glen B]

No need to parallel smaller value caps. Try four of a larger value, like 10,000uf. The user reported that the increased capacitance value in the blocker did further reduce mechanical transformer hum to an acceptable level.

[Curt C]

You could try a DC blocker circuit in series with the hot side of the transformer primary.

I'd like to add that the capacitors in the DC blocker circuit will be subjected to high ripple currents under load, and the expected ripple current should be considered when the caps are chosen.

Likewise, the diode's sole purpose in this circuit is to limit the ripple current to the caps by shunting the current at startup or under high loads. A 1K transformer can draw over 8 amps, for example. Consequently the diodes need to be sized to tolerate these conditions.

I used a 35A bridge rectifier, which cost only about $5, but will adequately protect the caps under just about any conceivable load. I also chose 40 Vdc computer grade caps (10K Vishay/Sprague in my instance) for their high ripple capabilities, large physical size, and reasonable pricing.

C

[Glen B]

Good suggestions. When increasing the caps values in the blocker I built, I also upgraded the diodes from 1A to 6A.