MGE Ultra-Isolation Noise Transformer, 5 KVA MODEL 91005-31T

pcosta

Well-Known Member
Jul 25, 2010
364
123
950
Windsor, Ontario, Canada
I am considering getting one of these MGE Ultra-Isolation Noise Transformer, 5 KVA. I would have it wired 240V in and 120V out.
Anyone with experience with one of these or something similar. What would be the positives or negatives of such and transformer.
 

zztop7

Member Sponsor
Dec 12, 2012
750
3
0
Edmonds, WA
Identical models - some hum, some hum loudly.
They are usually very warm.
Best to isolate them from the "listening to music room".

zz.
 

pcosta

Well-Known Member
Jul 25, 2010
364
123
950
Windsor, Ontario, Canada
This unit would be installed outside my "listening room". The seller has it in the closet of his listening room and says this unit is quieter than some of the cheaper Topaz transformers of the same size.
Does anyone know if it would behave quiet in all environments? For example if the unit is quiet in his room will it be as quiet in my room, or it is because his power is better than mine.
 
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zztop7

Member Sponsor
Dec 12, 2012
750
3
0
Edmonds, WA
Transformer plates like to talk.
Some are listeners.
Some converse more.
Some are the life of the party.
I am talking the same exact model; you never know till you own the beast.

zz.
 

cjfrbw

Well-Known Member
Apr 20, 2010
3,309
1,293
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Pleasanton, CA
Isolation transformers probably need to be "potted" in some manner to prevent the noise, but seldom if ever are.

The ones I have had tend to fluctuate in noise. Sometimes they are quiet, sometimes the lines set up oscillations that make them hum. You won't know until you try. I wouldn't count on one being quiet, even if has been quiet in another system, because you don't really know if it was "always" quiet in the other system if you haven't spent a lot of time with it.
 

InterMechanico

New Member
Apr 17, 2014
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Vancouver, Canada
I think that "potting" is pretty standard, since that process is the main factor in keeping a transformer quiet, but I may be wrong.

All things being equal, and the seller being honest, any noise the transformer could create would not be due to a deficiency in its' construction, if it has already been demonstrated to be quiet. I'm fairly certain that a noisy transformer cannot (easily) be quieted, although a quiet one could certainly become noisome in the right (wrong, electrically) environment. I have found that in my own system, the electrical supply to my residence made all the difference. I now live in a young condominium which supplies my unit with a very stable supply of 208 volt current. Everything is always very quiet, regardless of what appliances or coifing tools my girlfriend is using. At a previous residence, our entire cul-de-sac was supplied by one transformer, and that created all kinds of irritations when listening to music.

I suppose what I'm rambling on about is whether you can determine if you'll have a problem or not, before you make a purchase. In my mind (young, fallible), the following factors make transformer hum more likely:

1) Many homes drawing from one power transformer (on the pole) which will create fluctuations in voltage (before your breaker panel)

2) Current supply to your home in particular (low capacity) : e.g.- my condo has a 200 amp service, which I could not come close to needing, and holds perfectly steady at 117 volts no matter what ( I even put my lab scope on it for a few hours ). However, many older homes only have a 100 amp service. So, with upgraded appliances, lighting, etc..., it sets the table for large fluctuations in voltage, and thus, noisy transformers, among other things.
 
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ddk

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May 18, 2013
6,261
4,040
995
Utah
I am considering getting one of these MGE Ultra-Isolation Noise Transformer, 5 KVA. I would have it wired 240V in and 120V out.
Anyone with experience with one of these or something similar. What would be the positives or negatives of such and transformer.
I'm not familiar with your particular model but I've done a few installations for clients and myself using 7.5kva Eaton isolation transformers. On the positive side good transformers do clean up the noise and you end up with a more detailed and open sound. On the negative you lose timbre, macro dynamics, there certainly is a transformer sound. Wether you like it or not depends on your system and your musical tastes. I have as many clients who like it as those who dislike the transformer sound. My suggestion is to have your electrician wire it so you have the option to keep it inline or bypass it. That's how I installed it for myself and found out that even out of circuit the unit still manages to clean up the electricity quite a bit without any of the negative penalties when its plugged in line with the sound system's dedicated lines. This way you can try it for yourself and make your own conclusions.

david
PS. The Eaton transformers aren't potted and we generally install them outside. Eaton is a high end brand.
 
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pcosta

Well-Known Member
Jul 25, 2010
364
123
950
Windsor, Ontario, Canada
ddk

How did you wire yours. People speak of balance power. Would one of these be able to do that. Any comments or opinions on your Topaz vrs something like a Furman or a Silver Circle. Both are "isolation transformers". Silver Circle least expensive 5kva starts at over $5000.
 

ddk

Well-Known Member
May 18, 2013
6,261
4,040
995
Utah
ddk

How did you wire yours. People speak of balance power. Would one of these be able to do that. Any comments or opinions on your Topaz vrs something like a Furman or a Silver Circle. Both are "isolation transformers". Silver Circle least expensive 5kva starts at over $5000.

Let me give you some context so you understand where I'm coming from. In the past twelve years we've been actively looking for a good ac conditioner, we tried many industrial and audiophile products and except one never found anything that didn't have some kind of additive and negative quality, some more than others! The only product that didn't degrade/color the sound in one way or another was an industrial regenerator that I heard in Japan, but they cost over $100k and aren't available in the US.

I won't get into the junk but even the best isolation transformers we tried have a sound and certain qualities that we ended up not liking. The reason I recommend Eaton or Siemens is that they are world class companies, their isolation transformers are among the best engineered and cost a lot less than their audiophile counterparts of unknown origin. I've heard balanced power panels in several installations, whatever its theoretical advantages there's still an isolation transformer there and you can hear it. I'm sure that some here will come out praising it, fact is that once installed none have the ability to go back and forth to know what the balanced power panel is really doing! 5kva units that you're looking at are usually plug and play, meaning that you can just plug them in and they have one or more outlets on the back for you to plug your equipment in. In this case its easy, first plug it in on your music system's circuit, turn it on an off a few times and see what it does. Then start plugging in your equipment into the unit one at a time so you know exactly what's happening. The larger 7kva to 10kva units that we usually use need to be hard wired and professionally installed by a qualified electrician. In this case we have sub panel added to the main panel coming into the house with two circuits. One circuit goes to the transformer and we have a 40 - 60 amp receptacle on the output of the transformer and a 2nd receptacle connected to the other circuit by passing the transformer. Then we have a wire coming from the audio panel of the dedicated lines with the appropriate plug to try either circuit, i.e. in line with the transformer or bypassing it. You can also take the transformer completely off line by disconnecting its circuit. You need this ability to hear what the transformer is doing, your mileage is your own and depends on the system, location and personal preferences.

david
 

pcosta

Well-Known Member
Jul 25, 2010
364
123
950
Windsor, Ontario, Canada
David

Thanks for you answer.
This transformer I am looking at, the seller highly suggested it be wired from the main panel to a sub panel, then from there I would have either two or four breakers into my room.
 

ddk

Well-Known Member
May 18, 2013
6,261
4,040
995
Utah
David

Thanks for you answer.
This transformer I am looking at, the seller highly suggested it be wired from the main panel to a sub panel, then from there I would have either two or four breakers into my room.

That's fine, if you wire it the way I suggested you always have the option to go back and forth, which is important. Are you trying to clean up the sound or cure ground loops?

david
 

TP1

Well-Known Member
Apr 2, 2014
26
4
298
The ONLY place I buy transformers from is the UK. Absolute first rate quality at non-hifi prices. For around $1k, you can get a 5KVA balanced and isolating transformer. Stick a hifi label on it and you pay upwards of $5 K. The balanced transformer does about 85-90% of what a PS Audio P-10 does for the sound ( I have one of those too) at a fraction of the cost and it is fully isolating too.

The company is called Airlink transformers ( link below) - don't worry if you don't see the exact voltage you are after , just call or send them an email and tell them what you want . Custom builds are around the same price anyway. I have a couple of 5 KVA and a couple of 3KVA transformers for local voltage and a 5 KVA 230/110 - most were special build with multi-taps so I can select different voltages if need be. These guys supply the BBC and large industrial companies and they know a thing or two about what they do.

I have units from the "standard" range but with RFI/EFI screen but no filter

http://www.airlinktransformers.com/balanced_power_supply/
 

pcosta

Well-Known Member
Jul 25, 2010
364
123
950
Windsor, Ontario, Canada
That's fine, if you wire it the way I suggested you always have the option to go back and forth, which is important. Are you trying to clean up the sound or cure ground loops?

david
I think I will wire two of the four plugs that I have dedicated to my setup, and try just two through the transformer. Then I would have the option of trying both ways. If I like what I hear I will probably wire the others through the transformer.

I do not have any ground loops. My preamp and phono have ground lifting switches so I have those configured so I get zero hum as far as loops are concerned. I had a separate ground plate installed and ground isolating plugs wired, but I found zero benefit doing that. I may use that ground plate and have the new breaker box grounded to that. The main breaker box is grounded to a cold water pipe. I also only have a 100 AMP service. Too many large and small factories around that I assume would affect my power in my area.

The main thing I want to address is the physical hum I am getting from my amp. The power transformer hums, depending when I listen during the week it is very annoying walking into a quiet listening room and hearing that transformer humming. I know the amp was quiet at the dealers room. The builder of my amp says I have DC polluting my power, I borrowed an item from Blue Circle http://www.bluecircle.com/page129.html and it was very effective. It did what it was supposed to do, but I felt the it was a sonic compromise I was not willing to accept.

Paul
 

TP1

Well-Known Member
Apr 2, 2014
26
4
298
The power transformer hums, depending when I listen during the week it is very annoying walking into a quiet listening room and hearing that transformer humming. I know the amp was quiet at the dealers room. The builder of my amp says I have DC polluting my power,
Paul

As you know transformers cannot pass DC and they vibrate as a result which causes humming. An isolation transformer will also hum if DC is fed to it. It will only isolate ground loops and all you will be doing is feeding it DC rather than your amp T/F. Lighting dimmers are big culprits for spewing DC into home power but sometimes the DC may be coming from outside.

Frankly I think your amp builder should have anticipated this because it is a common issue. Using EL type transformers, potting T/F with resin etc greatly reduces humming and he could also install something like this to block the DC altogether:

http://www.lcaudio.com/index.php?page=316
 

Speedskater

Well-Known Member
Sep 30, 2010
941
15
368
Cleveland Ohio
If the transformer is not hardwired to the system (that is it's not just plugged into an existing wall outlet) it doesn't bring much to the party.

In any case, this Middle Atlantic paper has pages on a proper installation: (start at page 19)

"Integrating Electronic Equipment and Power into Rack Enclosures"
'Optimized Power Distribution and Grounding for Audio, Video and Electronic Systems'

http://www.middleatlantic.com/~/media/MiddleAtlantic/Documents/WhitePapers/PowerPaper.ashx
 

pcosta

Well-Known Member
Jul 25, 2010
364
123
950
Windsor, Ontario, Canada
As you know transformers cannot pass DC and they vibrate as a result which causes humming. An isolation transformer will also hum if DC is fed to it. It will only isolate ground loops and all you will be doing is feeding it DC rather than your amp T/F. Lighting dimmers are big culprits for spewing DC into home power but sometimes the DC may be coming from outside.

Frankly I think your amp builder should have anticipated this because it is a common issue. Using EL type transformers, potting T/F with resin etc greatly reduces humming and he could also install something like this to block the DC altogether:

http://www.lcaudio.com/index.php?page=316

Some of the problem could be blamed on the transformer, the builder is now supplying the amp with an air gapped transformer, and the case surrounding it has been more heavily damped. The hum is also amplified by the case. Problem is I cannot remove the tranny case and damp it so it doesn't ring because the bolts are covered by too much of the circuit. I would send it back but, he is on the other side of the Atlantic ocean.
When I had a pair of Lamm ML1's is hummed as well in the same room just not as loud and they had potted transformers.

I had a conversation with a tech at the Furman factory and he said one of their Symmetrical balanced power conditioners. He was quick to point out the hum may transfer to the conditioner.
 

Nyal Mellor

Industry Expert
Jul 14, 2010
590
4
330
SF Bay Area, CA, USA
Take a look at Torus Power :)
 

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