Discussion of AC mains isolation transformers

[Jud]

I have the 91001-32 which is 0.0005 pF 1000kV and $75

 

I also have the 91002-32 (30 amp) unit

 

These versions have the lowest interwinding capacitances I've seen.

 

Where did you find the 91001-32 for $75? I'm going to be talking to the electrical sub for our planned new home this week, and was thinking of finding a 91001-32 to isolate the audio system from the rest of the electrical system in the house. (I'll have a TV, Blu-ray player, DVR, etc., plugged into the system too, so let me know if 2.4kVA isn't enough.)

 

Edit: Sorry, I mean I'm looking for the 91002-32, which is the 2.4kVA model.

[Jud]

eBay with patience. $150 for the 91002-32

 

Perfect, thanks.

[Jud]

Is it beneficial even when you don't originally hear any noise our hum on your system?

 

Thanks in advance.

 

Joel

 

 

Hi Joel. I have not purchased an iso transformer sized for my entire system (though I plan to for the house my wife and I will be building in the near future). I have purchased a couple of small iso transformers for (1) my MacBook's SMPS, and (2) my preamp. I also placed a network isolator (though not a transformer) on one Ethernet connection from the router supplying network service to my system, and am awaiting delivery of a second isolator for the second connection from that router. Like iso transformers, it is a function of network isolators to stop leakage currents. https://en.wikipedia.org/wiki/Network_isolator

 

While making these changes, I have had in my system a device that serves the function of a "noise sniffer" (see for example Welcome to AudioPrism Noise Sniffer). It takes whatever noise you have in your system and amplifies it to the point where it is plainly audible. I can tell you that iso transformers and network isolators do work to reduce noise, since they made noise in my system inaudible even with the "sniffer."

 

A very interesting thing that I remarked about to a friend is that when the noise was inaudible, these measures subjectively resulted in the sorts of classic changes we've all described in these pages - better soundstage and imaging, more detailed intonation in vocals and instrumental playing, a greater sense of ease in listening.

 

So I know for a fact these things work to reduce noise, and my subjective impression is that even when noise was not audible they were beneficial in my system.

[Jud]

John - you keep mentioning a "simple single strip".

 

In my case, I would need to have a "simple single strip" plugged into the isolation transformer but I need to have at least one and possibly two additional "simple strips" plugged into the first "simple strip" in order to reach all my equipment. Obviously I could get longer power cords as well.

 

So my question is having multiple secondary strips coming off the main strip accomplish the same results?

 

 

Sent from my iPad using Computer Audiophile

 

This may help:

 

GE 6-Outlet Grounded Adapter-Spaced Tap-50759 - The Home Depot

 

https://smile.amazon.com/gp/product/B0027JPKIE/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

 

Audio Catalog

[Jud]

Hi Joel. I have not purchased an iso transformer sized for my entire system (though I plan to for the house my wife and I will be building in the near future). I have purchased a couple of small iso transformers for (1) my MacBook's SMPS, and (2) my preamp. I also placed a network isolator (though not a transformer) on one Ethernet connection from the router supplying network service to my system, and am awaiting delivery of a second isolator for the second connection from that router. Like iso transformers, it is a function of network isolators to stop leakage currents. https://en.wikipedia.org/wiki/Network_isolator

 

While making these changes, I have had in my system a device that serves the function of a "noise sniffer" (see for example Welcome to AudioPrism Noise Sniffer). It takes whatever noise you have in your system and amplifies it to the point where it is plainly audible. I can tell you that iso transformers and network isolators do work to reduce noise, since they made noise in my system inaudible even with the "sniffer."

 

A very interesting thing that I remarked about to a friend is that when the noise was inaudible, these measures subjectively resulted in the sorts of classic changes we've all described in these pages - better soundstage and imaging, more detailed intonation in vocals and instrumental playing, a greater sense of ease in listening.

 

So I know for a fact these things work to reduce noise, and my subjective impression is that even when noise was not audible they were beneficial in my system.

 

I received the second network isolator today and connected that. In addition, I have recently purchased two power strips without filtering, surge suppression, etc. These strips take IEC inputs. I'd had old MIT Z-Cords feeding them, but thinking of avoiding filtering, yesterday I substituted two ordinary Tripp-Lite IEC cords. So I've got the strips plugged into the wall with these cords, a couple of the network isolators (inexpensive b/c bought used), a couple of small (about 5" cube) inexpensive iso transformers, and the LPS-1. I had this combo together for the first time tonight and just had time to listen to a few songs, not too loud because my wife had gone up to bed.

 

The sound is effing amazing. Effortless clarity and beauty. All the nuances, all the little differences in the way things are recorded, even from track to track on the same album...I'm loving it.

[Jud]

Not Jud, but IIRC, he may have ordered one of these based on John's recommendation.

 

Audio Catalog

 

They are very nicely made and the price is hard to beat. But I think they took a long time to arrive.

 

Thanks, Alex. I ordered two of them, and they are indeed nicely built. They did take a while to arrive, because I selected the cheapest shipping method, surface from Hong Kong to the eastern US. You can have them shipped as fast as you like, but they are substantial so the speediest methods may be relatively expensive.

[Jud]

Jud,

I am glad you are having better sq! However, I am confused (and easily, cuz this whole subject has me a little confused). I thought that ONE power strip is the only way you won;t have impedance issues (when using mulitple power strips) and that the power strip plugs into the iso transformer, not directly into the wall. So where are your iso transformers and what is plugged into them (since your powr strips go to the wall) for you to get benefit?

Thx

Ted

 

P.S. I ask about multiple power strips and multiple isos especially because I have multiple uses for my music room and have my video/projector/surround equipment (except exasound mch dac) in the back of the room (due to projector fixed mounted and HDMI feed to pj), and can't reach any possible single power strip for the room. But they coexist because center and secondary preamp (front l/r for movies) 15 ft analog interconnects are plugged into front system.

Hi Ted. I imagine a single power strip (or a sufficient number of wall outlets) is the ideal situation. But I have only a single two-outlet plate behind my system, and way too much audio-visual equipment for a single strip. So I've got two strips, each connected by a plain 2 foot 14AWG TrippLite power cord to the wall (where I've got a multi-outlet adapter plugged into that single receptacle).

 

I listen to my main system using Audirvana+ with my laptop, and HQPlayer running on a desktop upstairs through an NAA (a CuboxTV). The source of music for both is an external HDD connected to the desktop upstairs. To access the HDD for Audirvana and to provide access to the NAA for HQPlayer, I have a router downstairs. The router has two Ethernet cable connections, one to either the laptop or the NAA, depending on which player I'm using, the other to a PS3 (not running when I'm listening, but on standby). To prevent leakage currents from using either of these Ethernet connections as part of a route through the system, I have Baaske isolators on both.

 

I also have two of the small B&K Precision 1604A iso transformers placed to try to keep leakage currents or other hash from power supplies from circulating through the system. I have the SMPS for the laptop plugged into one, and the El Cheapo that energizes the LPS-1 plugged into the other. Since the El Cheapo feeds the LPS-1, perhaps an iso transformer isn't needed there as much as it might be, for example, to plug the SMPS for the router into, or some other piece of equipment. I may experiment a bit with that.

 

Finally, I've got an old MIT Z-1 unit plugged into the wall, since it is supposed to help increase power factor.

 

I plan to get a large iso transformer for the entire system to run from, but that's going to wait for our next house.

[Jud]

@Jud those things are just empty cases, right? Are you building the power strips yourself?

 

You can get the cases separately if you want to build your own, but these are fully built power strips. No DIY beyond finding IEC cords to plug into them.

[Jud]

John: The advise to connect all your low power digital gear to a "single power strip" is to be able to use one iso-transformer for all that gear, or there is more to it? Please let me know. Thanks.

From John's post:

 

The recommendation of the simple power strip does NOT block leakage loops, it just decreases somewhat the noise generated by the leakage loops, the leakage current is still there. This is important if you have devices like DACs, preamps, poweramps etc that have their own AC power supplies, thus WILL have leakage loops.

 

So this has nothing to do with iso transformers, it is to lessen the impact (noise) from leakage current flowing among components.

[Jud]

So what are we saying; SIMPLE (no filtering, surge suppressor, etc.) or SINGLE or BOTH?

 

Simple single is best. If you don't have room for all your stuff on a single simple strip, use more than one with short large gauge power cords.

[Jud]

Hi Gents:

 

Happy Friday. I'm taking it a bit easy today. Was going to go to Fresno to pick tile and counter laminate for the UpTone shop bathroom and kitchenette, but there is a storm rolling in and the big Wilsonart laminate store closes in a couple hours anyway. So I'm just catching up on e-mail and forum stuff--and again procrastinating my year-end accounting.

 

Right now there seems to be a particularly nice selection of Topaz iso trans units on eBay, at surprisingly good prices:

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xtopaz+transformer.TRS0&_nkw=topaz+transformer&_sacat=0

 

A lot of the eBay sellers fail to indicate the kVA size of the units they are selling, if they were originally line-cord or terminal models, or the input/output voltage options. But they always list--or you can read from the listing photos--the model number.

So here is a link to the only model/spec sheet I have found to-date:

http://www.pacificparts.com/vends/mge/images/t1.pdf It is from MGE UPS Systems, the last firm to own/sell the line before Eaton bought them. I have seen other Topaz models outside of what is on the list, but it is a pretty good sheet for sizing what you are looking at.

 

Also, I recently discovered that Daitron--a Japanese conglomerate that we have known for a while for their ultra-low-noise SMPS units--has for many years (decades even?) been selling isolation transformers that are exactly the Topaz Ultra Isolators.

See: DaitronPower

 

Look at the photos of this one on eBay:

Daitron J 91005-11 Line Noise Suppressing Ultra-Isolator .005pF

 

Plus, on the current Daitron spec sheet, they are listed with interwinding capacitance of 0.0005pf, just like the best of the original Topaz units.

 

Given that they clearly are using the same end castings as the original, and that Daitron generally does its own manufacturing, I am wondering if at some point in the long and twisted history of the Topaz iso trans line (see this post) maybe Diatron bought some rights and tooling.

 

Myself, I am considering a big 5kVA unit to wire up for 240V in/out. My custom studio has a dedicated sub-panel--fed from our main panel by 25 feet of big 3/0 (all cryro-treated, including the bug panel and all home-run runs of Hovland Main Line to the outlets). As part of my new building addition (for the UPF--UpTone Production Facility ), I formed a new utility room (for new house HVAC, water, electric, and future solar control). So that is the perfect place for me to install a big humming iso trans to feed the studio sub-panel!

 

Here are some pics:

 

[ATTACH=CONFIG]31400[/ATTACH]

 

The sub-panel from back when I built the studio in 2004.

[ATTACH=CONFIG]31401[/ATTACH]

 

To prove that I'm crazy, a shot of the room between the 2 layers of 5/8" drywall. 760 4-inch squares (that I hand cut) of PolyDamp ADA viscoelastic constrained-layer damping material (really works!).

[ATTACH=CONFIG]31402[/ATTACH]

 

Lastly, John is coming to visit (work/play) in January, so I just added this very firm queen-size sleeper-sofa to the UPF. No more airbed in the studio! (Though with 2 of our 3 kids off at college, we do also have a regular guest room now.)

[ATTACH=CONFIG]31403[/ATTACH]

 

HAVE A GREAT WEEKEND EVERYONE!

 

--Alex C.

 

Alex, your utility room has a giant pink alien worm in it.

 

When John comes, better feed him to it to keep it friendly.

 

 

Sent from my iPhone using Computer Audiophile

[Jud]

https://i.kinja-img.com/gawker-media/image/upload/s--_whfIcdg--/c_fit,fl_progressive,q_80,w_636/1813aqov5wc2jjpg.jpg

 

That actually got a snort out of me.

[Jud]

So I finally decided to try and grab a Topaz-like transformer off Ebay, and with the help of a CA poster (ElviaCaprice) I grabbed a 1Kva one for cheap (which is good just in case this experiment doesn't work). It will replace my megaBuss as the conditioner for all my front end pieces (which are all going through a John Swenson-approved 15 outlet naked strip, then into the megaBuss). However, my DIY capability sucks as I am presented with this:

 

[ATTACH=CONFIG]33287[/ATTACH]

 

I have plenty of 3d party power cords laying around, with nice IEC connectors, etc. Can someone PM me the best instructions to replace (or God-forbid splice) into this.

 

The input side has two nice ac outlets, so I am fine there. Thanks.

 

Know a good electrician? Shouldn't cost much.

[Jud]

The way I test AC line noise is get a small 12V or 6V toroidal transformer, wire that with a power cord and a resistor on the secondary that pulls 50 to 100mA and run that into a standard scope. It is important to use the load resistor, I have found that many power transformers distort the waveform when unloaded. Putting a light load on the transformer gives very low distortion from the transformer itself and the toroids generally have fairly decent bandwidth for letting high frequency noise through.

 

I did a bunch of tests on my line about ten years again and a bunch last year. It is MUCH noisier now than it was ten years ago.John S.

 

All the smart and green stuff tends to make a lot of noise on the power line (even light bulbs and toasters now, plus all the small convenience appliances you didn't know you needed a decade ago).

[Jud]

Hi Ted,

sorry, no pictures, and there won't be any for awhile, a friend and I were packing up the listening room today.

 

WOW I found a bunch of records I didn't remember having! After things get setup in the new place I'm going to have to spend some serious time listening to records again!

 

 

John S.

 

I know it's OT, but would be curious to know what you use for playing records.

[Jud]

A turntable, maybe? [emoji12]

 

 

Sent from my iPhone using Computer Audiophile

 

 

Where is that "rueful grin" emoji when you need it?

[Jud]

A Well Tempered Record Player with upgraded platter, Shelter 501MKII, into Hagerman Picolo into Bottlehead Seduction.

 

I've had the turntable for something like 28 years. It is the only piece of gear I still have from my very first high end system.

 

John S.

 

They make mighty fine turntables. A good choice!

[Jud]

21 minutes ago, Speed Racer said:

I bought a 1.8KVA Topaz 91018-11 Line Noise Suppressing Utra-Isolator (.005pF) transformer and received it today. I plugged it in to a wall outlet and then plugged a TrippLite power strip with all my audio equipment (not the computer) into it.

 

The first bit of good news is that the transformer is virtually silent. If I stick my head right next to it I can here a slight hum but it is well below the ambient noise of the room with no music playing. I have no idea how clean or dirty my AC power is on the outlet I had the audio equipment plugged into. I can say that I think the noise floor is lower. In other words, the background sounds quieter. It's like the music is coming from a noiseless place. The details and clarity in the timbre of voices and instruments has improved. Finally, the separation of instruments and voices is even better than before.

 

Listening to Steely Dan's "Hey Nineteen" is amazing. The soundstage is fantastic. It is not too wide and the I can clearly discern the location of the various instruments better than before. Wow. I just listened to CCR's "Susie Q". Wow...just wow!! The clarity, separation, and detail are incredible!

 

Using the Topaz transformer and TrippLite power strip is certainly a step up in sound quality. I am impressed! Now I just need to get the ISO Regen to complete the setup and I should be done.

 

Proud purchaser of a Topaz 91002-32 a few days ago that's on its way to the electrical sub on our new home, so your story is, shall we say, music to my ears.

[Jud]

59 minutes ago, One and a half said:

 

Plug the Infeed to the transformer at the wall outlet.

 

Everything else audio related on the output side of the Iso transformer, via a non suppression type power strip.

 

For 48 bucks I'm fairly sure he's not talking about a tranny.

 

I've always gone direct to wall with the amp, but if we're just talking about a power strip and not a huge difference in power cord gauge between amp and Tripplite, I don't see why you couldn't go through the strip.

 

May as well try it both ways and if it sounds bad one way, do it the other.

[Jud]

11 hours ago, One and a half said:

 

The "ideal" is to have all the audio components at the same potential. Due to the regulation of the ISO transformer and the AC mains, there will be differences. These differences will cause the 0V of a source to be higher (above ground) than if it were connected to the same power strip. "Higher" will cause more shield current to flow, and also more noise with it. 

I would discount and loss of dynamics for the amp going through an ISO transformer, since that's largely an old wives tale related mainly to power conditioners with caps, inductors that really screw up impedances between the load and the conditioner. 

 

Yes, my point was (though I could be wrong) I didn't think Ralf11 was referring to using an iso transformer at all when he mentioned he wanted to try something that would cost $48.

[Jud]

1 hour ago, lmitche said:

Joel, well both really.  I reached the same conclusion experimentally here, read John's post confirming the superiority of the design, and then followed the success of the same on Jud's system, and been reading about the success of many others on CA.

 

Yep, though to be absolutely precise, I’ve got two power strips (8 receptacles per strip and >8 plugs) and my amp, each of which is plugged into the same wall receptacle on the same circuit.  So no isolation among components, and yes, noise is reduced in this configuration compared to when I had some components plugged into an MIT strip with isolation.  (Some folks will remember I had a test component that picked up noise very audibly from my computer’s SMPS.  So I used this with the SMPS plugged in as a test setup to see what configuration lowered the noise level.)

[Jud]

1 hour ago, joelha said:

Only my amps are in the basement, on shelves attached to the ceiling, to give them the shortest speaker cable run to the speakers immediately above them.

 

That configuration also allows me to keep the speaker cables and XLR cables to the amps out of sight

 

So the entire front end is on the main level. Only the amps are in the basement. My concern with plugging the amps into the main level isolation unit (if I were to get a unit with enough capacity to handle them) would be the very long runs of power cables necessary to connect them to that isolation unit.

 

Joel

 

This says to me that you will (also) have to determine whether it’s more important to have shorter power cables or shorter speaker cables.

[Jud]

Thanks John - helping people be safer is one of the best things we can do.

[Jud]

OK guys, dumb question to which I hope to get a quick answer: Should an isolation transformer be used with isolated ground receptacles?

[Jud]

4 hours ago, Speedskater said:

Isolated Ground receptacles/systems are only useful in buildings that have metal conduit/tubing or metal building framing. They prevent ground currents from other circuits from using your interconnects as a path back to their voltage source.

 

Thanks - I already re-sent the electrician the Middle Atlantic white paper and said unless I was missing something it didn’t look like isolated ground receptacles were needed.