Medical Isolation Transformer for DACs

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mresseguie

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Medical Isolation Transformer for DACs
« on: 31 Jul 2017, 05:24 am »
Who has tried using these?
What results did you notice?
Which model(s) did you audition/buy?
Do you still use it?
Does it only work for DACs? What about CDPs?

Is this any different from the PI Audio DigiBUSS or similar?

This sounds really interesting.

Thanks for any input!

Michael

bacobits1

Re: Medical Isolation Transformer for DACs
« Reply #1 on: 31 Jul 2017, 10:13 am »
Michael, which ones?
Not familiar with these?
I understand we are doing bran surgery but...... :scratch:

lokie

Re: Medical Isolation Transformer for DACs
« Reply #2 on: 31 Jul 2017, 01:11 pm »
I have one w 2 sockets. I bought it cheap through a surplus store.
It is a serious piece of equipment that cost thousands of dollars new. I plug various digital stuff in it. Anything i think might add noise in the lines.

Mine is dead quiet but I have read where others are not. It has no effect on sound... good or bad.  I recommend trying it.

It looks something like this:

http://www.ebay.com/itm/MGE-91092-32T-UPS-Ultra-Isolation-Transformer-120v-250VA-60Hz-120VAC-0-0005pF-/263015448895?hash=item3d3cf1413f:g:ICcAAOSwsXFZMI9o

Speedskater

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Re: Medical Isolation Transformer for DACs
« Reply #3 on: 31 Jul 2017, 01:52 pm »
Most DACs have a SMPS, in a few cases an Isolation Transformer may reduce power line noise coming out of the DAC's supply to other components.  The DAC itself shouldn't much care about power line quality.

DaveC113

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Re: Medical Isolation Transformer for DACs
« Reply #4 on: 31 Jul 2017, 02:49 pm »
They can help somewhat but noise reduction is not the primary purpose and they are of limited benefit when there is noise on the AC line. A dedicated emi/rfi filter works much better. If you use one it needs to be oversized so it doesn't have a negative effect. IMO it's superfluous.

An example is an Equitech BPT being unable to get rid of harshness and glare due to AC noise vs a SurgeX. The SurgeX solved the problem, Equitech did little to nothing in this case. Which is what you'd expect as a BPT is not an emi/rfi filter and neither is an isolation trafo.

Folsom

Re: Medical Isolation Transformer for DACs
« Reply #5 on: 31 Jul 2017, 04:37 pm »
Some are better than others, but I never recommend transformers. In fact I can say Equi=tech's are not ok until they have some treatment.

They'll say if they actually reduce noise, too.

Most DACs have a SMPS, in a few cases an Isolation Transformer may reduce power line noise coming out of the DAC's supply to other components.  The DAC itself shouldn't much care about power line quality.

An insane statement from an otherwise mostly sane person.

As far as SMPS's, it depends on their design too. They're often nasty at common mode noise. But one of the problems is the ground on SMPS's can be made ripe with noise, and transformers & such don't do much about that.

Wind Chaser

Re: Medical Isolation Transformer for DACs
« Reply #6 on: 31 Jul 2017, 04:45 pm »
Who has tried using these?

I have been using them in for the past 7 years.

Quote
What results did you notice?

The wholesale transformation of $300 DAC, to the point where it compared very favorably against a very well regarded $3000 DAC. And it wasn't just me who heard this; the distributor of the $3000 DAC heard it too, and asked me not to publish my findings - to which I agreed, so that's why I won't mention the brand or model of that DAC.


Quote
Which model(s) did you audition/buy?

Mine are made by Cyber Care Part Number: 790015


Quote
Do you still use it?

I briefly took it out of the system and replaced it with an Astron regulated power supply. The stock SMPS plugged into the MIT is superior in every way. I will keep my MITs forever.

Quote
Does it only work for DACs? What about CDPs?

Yes, it will works with CDPs too.

Wind Chaser

Re: Medical Isolation Transformer for DACs
« Reply #7 on: 31 Jul 2017, 04:53 pm »
Michael,

I should add that if you are ever in this area again, you're welcome hear what my system sounds like with, and without the MIT in the loop. The difference is far more obvious and positive than that of any power cord I've ever tried. Having said that, my experience with audiophile power cords is quite limited to just 3 cords ranging in price from $100 - $1000.

wushuliu

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Re: Medical Isolation Transformer for DACs
« Reply #8 on: 31 Jul 2017, 06:24 pm »
Another plug, so to speak, for the Hammond 193L/193M tweak for all things digital (including TV/projection).

http://www.audiocircle.com/index.php?topic=130672.20

Armaegis

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Re: Medical Isolation Transformer for DACs
« Reply #9 on: 31 Jul 2017, 07:37 pm »
I have a couple big boxy Tripp-Lite isolation transformers. No degradation as far as I can tell.  No magical improvements either, but that's not what they're for.

mresseguie

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Re: Medical Isolation Transformer for DACs
« Reply #10 on: 31 Jul 2017, 07:51 pm »
Cool stuff. Good info from both sides. Thanks!

John,

I have to return someday- the BEST apple strudel in North America is to be found in your house. :thumb:

Letitroll98

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Re: Medical Isolation Transformer for DACs
« Reply #11 on: 31 Jul 2017, 08:25 pm »
I have one w 2 sockets. I bought it cheap through a surplus store.
It is a serious piece of equipment that cost thousands of dollars new. I plug various digital stuff in it. Anything i think might add noise in the lines.

Mine is dead quiet but I have read where others are not. It has no effect on sound... good or bad.  I recommend trying it.

It looks something like this:

http://www.ebay.com/itm/MGE-91092-32T-UPS-Ultra-Isolation-Transformer-120v-250VA-60Hz-120VAC-0-0005pF-/263015448895?hash=item3d3cf1413f:g:ICcAAOSwsXFZMI9o

That looks just like mine, also bought at a surplus store, I thinks around $20-30.  I plug the old Oppo and DAC into it.  The guy had two and I bought one to see if it would work, went back for the other one and it was sold, maybe that's you.

mcgsxr

Re: Medical Isolation Transformer for DACs
« Reply #12 on: 31 Jul 2017, 09:56 pm »
I use a OneAC unit in my media closet.  I run my gigabit switch, router and another peripheral off it.

I had in the past used one on a DAC.  I later went to a Felicia type power conditioner for the DAC.

doggie

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Re: Medical Isolation Transformer for DACs
« Reply #13 on: 1 Dec 2017, 12:46 am »
Here is a link to a thread on Head-Fi that has excellent information on what to look for in an isolation transformer. I use a Topaz unit with good results. They come up frequently on eBay. Look for one in the "30" series that meets your electrical current needs.

https://www.head-fi.org/threads/topaz-low-capacitance-isolation-transformers-for-affordably-clean-power.857448/


FullRangeMan

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Re: Medical Isolation Transformer for DACs
« Reply #14 on: 1 Dec 2017, 01:07 am »
Medical trafos requirements are reliable and safe not good sound. In 2003/4 I used for more than a year two 4.5kg Toroidals made to order transformers to 220V->120V in a CD player, obviously when I removed the trafo and used the CD direct at the wall the SQ improved to my surprise, the trafo leads even were QED Silver Anniv 2,5mm speaker cables.

maty

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Re: Medical Isolation Transformer for DACs
« Reply #15 on: 1 Dec 2017, 08:18 am »
You know I have VERY BIG problems with noise, RF/EMI interferences, DC at mains, high voltage (near 240 volts vs 230 volts)... Years ago I came to the conclusion that the use of Schaffner RF/EMI filters and Würth 150 kHz ferrites was more economical and effective.

Isolation transformers make sense if amplifiers with very BIG transformers are used.

USB Isolator: iFi iUSB vs TeraDak U9VA + Teralink ADuM4160. Filtros Schaffner. Lampizator: AC filter DIY ESA SILK. Estabilizador / regulador de tensión / voltaje. Isolation / Balanced transformer. DC Blocker / Blocking. PC SILENCIOSO en Aussar. Variac.

[Spanish]    http://aficionados.foroactivo.com/t197-usb-isolator-ifi-iusb-vs-teradak-u9va-teralink-adum4160-filtros-schaffner-lampizator-ac-filter-diy-esa-silk-estabilizador-regulador-de-tension-voltaje-isolation-balanced-transformer-dc-blocker-blocking-pc-silencioso-en-aussar-variac

And a line dedicated with super immune breakers is a good idea too.

maty

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Re: Medical Isolation Transformer for DACs
« Reply #16 on: 1 Dec 2017, 08:20 am »
Re: Icepower 1200AS amp. Class D like you've never heard before

http://www.audiocircle.com/index.php?action=post;msg=1647460;topic=153645.840

Quote
In Europe, Schnneider residual current Super immune circuit breaker is a very good idea if you have a dedicated line to audio equipment => additional protection in front the harmonics at mains in polluted environments and networks.

Why?

The electricity network is getting dirtier every day. The widespread use of cheap SMPS, cheap electrical motors, air conditioners (they add DC at mains too)....  usually made in East Asia (China). And bad electrical installations in elevators, and...


https://www.schneider-electric.com/en/search/inmmunized

https://www.schneider-electric.com/en/search/Super+immune

maty

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Re: Medical Isolation Transformer for DACs
« Reply #17 on: 1 Dec 2017, 08:31 am »
Hard with EI or toroidal transformers:

Re: Folsom's great little 7297 Chip Amp

http://www.audiocircle.com/index.php?topic=138229.msg1644983#msg1644983

Quote
Earth loop-breaker boards

-> https://hoppesbrain.com/2017/05/26/earth-loop-breaker-boards/

[IMG] http://hoppesbrain.files.wordpress.com/2017/05/diode-shunt-loop-breaker.png


The ARTICLE, by Rod Elliott (1999)

Earthing Your Hi-Fi – Tricks and Techniques

-> http://sound.whsites.net/earthing.htm

[IMG] http://sound.whsites.net/earth-f4.gif

and...

http://www.audiocircle.com/index.php?topic=138229.msg1644988#msg1644988

Quote
6A is too much with only 15 watts amp!!!! It is better idea to use the lowest possible amperage because they attenuate much more.

Schaffner F2244B:

[IMG] http://maty.galeon.com/WP-imagenes/hard/IEC-inlet-filter-Schaffner-FN_9244-specs.png

The graphs: [IMG] http://maty.galeon.com/WP-imagenes/hard/IEC-inlet-filter-Schaffner-FN_9244-typical-filter-attenuation.png

[IMG] http://maty.galeon.com/WP-imagenes/hard/IEC-inlet-filter-Schaffner-FN_9244-cicuit.png

I can use Würth 150 kHz ferrites with the power cables (besides the RF/EMI filters). The usual problem in audio is in the RF < 1 MHz.

The ferrites (and very cheap) that are usually seen there are for EMI ( > 1 Mhz), so they are not very useful in audio. They are useful with video.

BIG transformers -> much more amperes -> Isolation/balanced transformers.

With a CD player, DAC, preamp, amplifier with transformer < 400-500 VA ... filters and ferrites.

Schaffner RF/EMI filters and Würth 150 kHz ferrites have the best specs.

FullRangeMan

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Re: Medical Isolation Transformer for DACs
« Reply #18 on: 1 Dec 2017, 02:44 pm »
The transformer I used was only 500 or 600W, when I remove it I started be supplied by the transformer from my condo that was a big 225KVA trafo, so I was no more power limited to a small 500W trafo.

Use an external transformer is limiting the power to your audio equipment.

jea48

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Re: Medical Isolation Transformer for DACs
« Reply #19 on: 1 Dec 2017, 03:03 pm »
Some are better than others, but I never recommend transformers. In fact I can say Equi=tech's are not ok until they have some treatment.

They'll say if they actually reduce noise, too.

An insane statement from an otherwise mostly sane person.

As far as SMPS's, it depends on their design too. They're often nasty at common mode noise. But one of the problems is the ground on SMPS's can be made ripe with noise, and transformers & such don't do much about that.

.
Quote

As far as SMPS's, it depends on their design too. They're often nasty at common mode noise. But one of the problems is the ground on SMPS's can be made ripe with noise, and transformers & such don't do much about that.

What ground? A true medical grade isolation transformer floats the secondary. Both power lines of the secondary are intentionally left floating above ground. Neither of the two HOT secondary leads will have a reference to ground.