[Energy]

Does anyone know where I can get one? I will shorten the cable, increase the wire gauge, put it into an aluminum enclosure with a faraday cage, and fill the inside with roxul to silence the hum. Does anyone have a unit that doesn't hum?

I was going to get a Tripp-Lite IS100HG but this seems like a no brainer per John's recommendation and thorough explanation.

 

[Zenvota]

Is there seriously nothing like it still in production? I find that bizarre if they are so great (which I'm not doubting).

Eaton power supress 100
I believe these r they, new for $600+
https://www.powercom.com/eaton-powe...s-100-500va-75kva-power-conditioner-hardwired

I picked up a 250va topaz .0005 for $30 though...

 

[Superdad]

I picked up a 250va topaz .0005 for $30 though...

Great score!

 

[Alcophone]

Eaton power supress 100
I believe these r they, new for $600+
https://www.powercom.com/eaton-powe...s-100-500va-75kva-power-conditioner-hardwired

I picked up a 250va topaz .0005 for $30 though...

Heh. Can't argue with that.

 

[zilch0md]

Eaton power supress 100
I believe these r they, new for $600+
https://www.powercom.com/eaton-powe...s-100-500va-75kva-power-conditioner-hardwired

I picked up a 250va topaz .0005 for $30 though...

So far as I can tell, any mention of interwinding capacitance is conspicuously absent in the specifications for those new Eaton isolation transformers.

I'd just as soon buy a $100 500VA Tripp-Lite brand new, if I was willing to forgo the benefits of a 0.0005 pF capacitance.

Those new Eaton's might actually be worthy of the old Topaz -30 and -31 models, but if so, why aren't they publishing or even boasting about the spec?

As John Swenson once wrote (paraphrasing heavily from memory), today's off-the-shelf isolation transformers offer almost no noise suppression above 400 Hz, for audiophile purposes - due to their poor (high) inter-winding capacitance. Not just any isolation transformer will give you significant common-mode noise suppression well past 20,000 Hz.

The Topaz 0.0005 pF transformers are a perfect example of a technology that has been lost to time. The actual knowledge of how to design them may even be lost. We might no sooner be able to manufacture such transformers today than we can put a man on the moon anytime soon. We have to re-invent that wheel barrow from scratch. Mankind did it in the past, but we can't do it now. (Oops! Here come the conspiracy theorists.)

 

[Zenvota]

From the CA thread:

"Finally a response from Eaton on their Power Suppress 100:

We do have testing on our 1kVA T100 and the interwinding capacitance is about 0.90pF. This is greater than the 0.005pF that is referenced below, but with the output filter network in play, the apparent noise attenuation is -136dB."

So ya better then the tripp lite but not as good as the old topazes

 

[zilch0md]

^ Thanks for this valuable info, Zenvota! Let me add that using more modern approaches to common-mode noise suppression comes with some pitfalls, but I will leave it to some of the more savvy contributors to reinforce (or rebut) what I'm saying.

I just can't remember the specifics, but in the end, I do recall that we are better off achieving the desired noise suppression across the full audio spectrum without inserting caps and such (L-C networks ?) on the secondary output of the transformer.

 

[Zenvota]

That's what it sounds like when they say theres an output filter network.

 

[sahmen]

So how do these look in terms of specs, and also price? They alll seem to meet the "series 30" specs, but I do not know what else to look for... I also want to get a sense of what a "reasonable" price range is for these units... Thanks for any helpful thoughts.

1
https://www.ebay.com/itm/MGE-UPS-Sy...179634?hash=item544002d272:g:3pQAAOSwJ7RYTRO2

2.
https://www.ebay.com/itm/MGE-UPS-Sy...288193?hash=item4b46ea01c1:g:6G4AAOSw0IJbLBXJ

3
https://www.ebay.com/itm/MGE-UPS-Ul...838565?hash=item2141431ea5:g:AXQAAOSwU4hbGyUS

4
https://www.ebay.com/itm/MGE-UPS-Sy...621511&hash=item285d7da1df:g:jM8AAOSwetNbKWhV

5.
https://www.ebay.com/itm/MGE-91097-...539609?hash=item3d4a3d5959:g:w9IAAOSwFhFZ0Dd9

 

[zilch0md]

^ Good hunting!

Specs for the -31 and -32 models can be found in this PDF: http://www.pacificparts.com/vends/mge/images/t1.pdf

Prices seem to be a bit high, overall, but when you search for anything on eBay, you can look for a checkbox along the left side of the screen that says "Completed Auctions" - so that you can see what similar items sold for in the past.

 

[Energy]

@zilch0md

Mike. Does your Topaz make any audible hum at all?

I'm currently looking to put a 2.5kV Topaz into an aluminum chassis..
First I would unbolt it from the metal frame that it comes in followed by routing 8-gauge wires to the IEC and Receptacles.

I noticed some people say that their unit hum. Because of that, I was planning on equipping custom heatsinks to the sides of the transformer and filling the empty area between the transformer and the chassis with some ROXUL (fiberglass equivalent) to suppress the noise. Then I realized since there will be a decent amount of space, I could easily build a DC filter to remove any DC offset. What would your opinion be on the matter?

Thanh

 

[zilch0md]

@zilch0md

Mike. Does your Topaz make any audible hum at all?

I'm currently looking to put a 2.5kV Topaz into an aluminum chassis..
First I would unbolt it from the metal frame that it comes in followed by routing 8-gauge wires to the IEC and Receptacles.

I noticed some people say that their unit hum. Because of that, I was planning on equipping custom heatsinks to the sides of the transformer and filling the empty area between the transformer and the chassis with some ROXUL (fiberglass equivalent) to suppress the noise. Then I realized since there will be a decent amount of space, I could easily build a DC filter to remove any DC offset. What would your opinion be on the matter?

Thanh

My 500VA Topaz has a wee bit of audible hum, but I have to hold my head no farther than about 300cm to hear it, even when the room itself is silent. If you search this thread, you can find posts by others, more knowledgeable than I, who have advised that tightening the bolts which hold the transformer together can make a difference, but my understanding is that, in general, the more hum you get from a transformer, the dirtier the incoming power is and certainly, DC offset can be a culprit. My incoming power is apparently "cleaner" in this regard than those who suffer a lot of transformer hum.

That said, the "guru" of using isolation transformers for noise suppression, Jon Swenson (of Uptone Audio), eschews the use of DC filters to silence his own humming Topaz. If I remember correctly, from posts he has made to a forum at ComputerAudiophile.com, he advises that we not use DC filters, that we instead just allow the transformer to do its job, even it hums. I clearly recall his writing that he built a wooden box around his transformer that has some kind of sound-deadening material in it, but he has gone out of his way to ensure that the transformer doesn't overheat - the box is well ventilated.

On reading your intent to use ROXUL to suppress the noise, my first concern was that you might interfere with the transformer's ability to stay cool. That said, I pull so little power from my transformer, operating a DAC and headphone amp, not a powerful speaker amp, that it never gets even warm to the touch. It pretty much remains at ambient temperature - but it's not enclosed in an insulated case.

So... my advice, which is mostly the advice of someone I respect, is to avoid DC filters and build a much larger box than you had perhaps planned, preferably out of sound-absorbing wood, using no (sound-radiating) heat sinks. You might even try to research the purchase of an extremely silent-running fan (that's small and turns at a low rpm) - just a little bit of forced airflow could allow you to shrink the box that baffles the sound. :-/

Mike

 

[Superdad]

That said, the "guru" of using isolation transformers for noise suppression, Jon Swenson (of Uptone Audio), eschews the use of DC filters to silence his own humming Topaz. If I remember correctly, from posts he has made to a forum at ComputerAudiophile.com, he advises that we not use DC filters, that we instead just allow the transformer to do its job, even it hums. I clearly recall his writing that he built a wooden box around his transformer that has some kind of sound-deadening material in it, but he has gone out of his way to ensure that the transformer doesn't overheat - the box is well ventilated.

Hi Mike:
I think the reason John adviced against use of DC-offset blocking networks was concern for safety—as failure of such can result in a fire. Given that these are used on the primary side, I don’t think he was advising against them for performance reasons.

Of course on the secondary side it is important to use outlets/power strips that have zero filter elements at all. The whole concept being to reduce the impedance between the grounds of all attached equipment (reducing the interaction of the inevitable leakage loops which form between all components with AC-connected power supplies). And the point of the isolation transformer is simply that it is a VERY effective surge suppressor and line noise filter.

BTW, here in the USA DC offset in our AC lines is rather rare. Occurs much more in Europe. Even there, blocking of the offset is not a sure-fire cure for transformer lamination hum. Such is a bit inevitable with big trannys—and it is often worse in 50Hz countries.

 

[kazsud]

I’ve had a hell of a time getting rid of static, pops and other noise in my house. First thing I discovered was there wasn’t a ground in my basement. So I installed a 8ft grounding rod which didn’t help much.

So I hired a electrician friend to come access the problem. He found the line that came from the duplex was going thru a light before going to the box. I had him install two hospital grade duplex and ran them to the box.

That got rid of 90% of all the noise but still audible. I have everything connected to a Furman M-8DX which conditions as well. His boss who is a audiophile said the last of the problem is probably coming from outside the house and suggested getting a Pure Sine battery converter.

After searching I found too many with all different t power handling. My only other idea is to get a PS Audio Noise Harvester.

Any input or thoughts?

 

[Zenvota]

Got a couple noob questions

Attaching a metal electric box to the transformers do you just use the wire clamps or some kind of threaded pipe?

Using an ac receptacle on the output with a metal box is there any necessary requirements like using an outlet with an isolated ground or does that not matter?