Isolation transformer effect on sound experiences

[SIY]

Also SET amps ? How are these designed ? It’s a factor .

“Normal” amps have property called PSRR “power supply rejection ratio” it can be in 100dB range so the circuit design itself of modern amps helps with defeating gunk from the power supply .

Botique brand audiophile amps with some kind of faith based design rather then electrical engineering may not behave a normally . The prior sentence may seen as absurd and slightly provoking. That’s not my intent .
But it’s actually what’s happening a very simple design with little or no global feedback may have low PSRR because the designers sacrificed this because “negative feedback is evil” or similar priorities a real engineer won’t have , the faith based designer will accept real problems in exchange of solving imaginary ones .

Isolation transformers or special filters should not be needed normally. That said I was once suckered inte buying an Isotek main strip it still in use .

Just to throw one more log on the fire, the two phono preamps I’ve designed in the past ten years or so, where noise is a significant issue, have zero overall feedback, single ended triodes or transformerless push pull, but have extremely high power supply rejection.

Engineering.

 

[Mnyb]

Just to throw one more log on the fire, the two phono preamps I’ve designed in the past ten years or so, where noise is a significant issue, have zero overall feedback, single ended triodes or transformerless push pull, but have extremely high power supply rejection.

Engineering.

You should probably know , if read this forum correctly you can actually design amps preferably tubed but with real performance

 

[SIY]

You should probably know , if read this forum correctly you can actually design amps preferably tubed but with real performance

I’ve designed one or two...

 

[Arno Fennix]

Also SET amps ? How are these designed ? It’s a factor .

Own design, interstage transformer coupled 300B. Anything specific you want to know?

 

[MrPeabody]

For some years I had 2 1500VA isolation transformers laying around for trying these in my audio system.
For the mains supply to the audio there is a dedicated power line and for all small consumers these are fed via an Isotek filter unit.
Before I tried to also feed the 2 power amps (SET 300B) via the isotek high power outputs but this did kill the dynamics a lot.

So, yesterday, connected the SETs to the 1500VA isolation transformer and an extra cable for attaching the "earth" wire.
Listening to music and I am amazed by the difference. Harshness disappeared (high mids / highs). When connecting the "earth" some of that seemed to come back again.

First steps, and I am working towards some measurements and options to switch faster between with/without isolation transformer for further listening tests.

Anyone tried these kind of comparisons (W/WO) by listening as well as measuring. What are your experiences?

I've read this post about a dozen times, and each time I read it, it bothers me more than it did the previous time I read it.

You said that you were "amazed" by the improvement in sound quality with the isolation transformer. But you didn't say a single word about why you suppose the isolation transformer is able to have the effect that you believe it has. I would not do something like this. If I did not think I would be able to offer a plausible explanation as to how the effect could be real, I would not have asserted that it was a real effect, no matter how strongly I believed that I had heard the effect.

You wrote, "Anyone tried these kind of comparisons (W/WO) by listening as well as measuring." You are once again insinuating, just as you have previously, that (1) anytime anyone believes they hear a difference they should trust their hearing and pay no attention to "measurements", and that (2) whenever anyone doubts whether you hear the things you say you hear, they do so because they only believe what they see in measurements and pay no attention to what they hear. This is a recurring theme of your posts. You seem to be concerned expressly with "measurements" in a way that doesn't seem quite correct. The concern that many people here share is with the question of whether, when you don't know whether you are listening to A or to B, you can reliably demonstrate that you can hear the difference between them. "Measurements" do not really play any strong role in this fundamental concern.

 

[Arno Fennix]

I've read this post about a dozen times, and each time I read it, it bothers me more than it did the previous time I read it.

Don't read it again please, there was no intention to bother anyone

You said that you were "amazed" by the improvement in sound quality with the isolation transformer. But you didn't say a single word about why you suppose the isolation transformer is able to have the effect that you believe it has. I would not do something like this. If I did not think I would be able to offer a plausible explanation as to how the effect could be real, I would not have asserted that it was a real effect, no matter how strongly I believed that I had heard the effect.

People are different. I do research in many ways, especially in areas where there are a lot of assumptions I want to experiment and experience. By the way, never expected the isotransformers would have certain effect.

You wrote, "Anyone tried these kind of comparisons (W/WO) by listening as well as measuring.

How great it would be the question is answered...

 

[Vuki]

This is the one I made. I like it. Sorry it's in Croatian - google translate is your friend.

 

[Arno Fennix]

This is the one I made. I like it. Sorry it's in Croatian - google translate is your friend.

This is a great contribution, Thank you!
(Google did a great job by the way ;-) )

 

[SIY]

Don't read it again please, there was no intention to bother anyone



People are different. I do research in many ways, especially in areas where there are a lot of assumptions I want to experiment and experience. By the way, never expected the isotransformers would have certain effect.


How great it would be the question is answered...

What you do is neither research nor experiment. Don’t pretend otherwise, that’s intellectually dishonest.

 

[rdenney]

I had a power-supply hum in a cheapie microphone mixer I was using to record myself during Covid. I wondered if common-mode 60 Hz was getting past its little wall wart, or whatever. And I figured having it around might be useful at some point, so I bought a used 500-watt medical-grade isolation transformer. No help, of course--the problem with cheap crap is that it was cheap crap. But I still use the transformer for everything but my amps, in the "what harm could it do?" department. And it gives me a convenient master off switch if I ever needed it. And, if any of the stuff I'm using is sensitive to noise that might get past my surge suppressor, this will help knock that down, too. Out here in the country, power is not always particularly clean.

I certainly did not hear any difference in anything plugged into it.

Rick "all sorts of things might be sorted by moving stuff around that isn't making clean connection" Denney

 

[Arno Fennix]

What you do is neither research nor experiment. Don’t pretend otherwise, that’s intellectually dishonest.

Let's try to be kind, humble and constructive...

If you got first-hand experience on the subject of iso-transformers including measurement and listening,I am looking forward to it

 

[Harmonie]

Just wondering, if my setup doesn't give similar results than an isolation transformer:

I use a dedicated circuit breaker and it's 50 feet shielded AC .
Doesn't that isolate quite a bit ?

 

[SIY]

Just wondering, if my setup doesn't give similar results than an isolation transformer:

I use a dedicated circuit breaker and it's 50 feet shielded AC .
Doesn't that isolate quite a bit ?

Not in the sense that an isolation transformer does.

 

[SIY]

Let's try to be kind, humble and constructive...

If you got first-hand experience on the subject of iso-transformers including measurement and listening,I am looking forward to it

My first experience with isolation transformers was likely before you were born. I have the misfortune of understanding how they work, where they're useful, and what they do and don't do. So unless someone does an EXPERIMENT showing an audible effect beyond removing a ground loop or a DC offset, I see no reason to do "listening tests." And frankly, you have done no listening tests and no experiments. Just make-believe. That's not going to get anyone competent to bother doing completely useless experiments because you're too lazy to do them yourself.

 

[Doodski]

Just wondering, if my setup doesn't give similar results than an isolation transformer:

I use a dedicated circuit breaker and it's 50 feet shielded AC .
Doesn't that isolate quite a bit ?

The shielding on your 50' of cable is very different than a isolation transformer's isolation and the principles behind the operation are entirely different. I've used a large isoXformer for isolating high voltage equipment and making it more safe to work on. I connected many audio amplifiers to it and never noticed any changes in the sound. It's hogwash.

 

[Harmonie]

@SIY & @Doodski
Thanks for your remarks, at least I don't have any issues with bulbs, neons and else parasites.
It wasn't intended to ~purify~ the sound anyway.
But when you run so many AC lines together from the mains to each room, one may believe in inductance and noise radiation EMI aso.

 

[SIY]

But when you run so many AC lines together from the mains to each room, one may believe in inductance and noise radiation EMI aso.

Unfortunately, an isolation transformer will not affect those very much. Fortunately, the impedances of these lines are low, so radiative pickup tends to be more of an RF issue. That is usually dealt with by having a couple of small capacitors from each side of the line to the chassis, or better yet, some simple filtration often built into PEMs.

 

[Doodski]

run so many AC lines together from the mains to each room, one may believe in inductance and noise radiation EMI

The power supply designs will take care of these issues and as a final blow to them they will get filtered out in the power supply output.

 

[Arno Fennix]

My first experience with isolation transformers was likely before you were born. I have the misfortune of understanding how they work, where they're useful, and what they do and don't do. So unless someone does an EXPERIMENT showing an audible effect beyond removing a ground loop or a DC offset, I see no reason to do "listening tests." And frankly, you have done no listening tests and no experiments. Just make-believe. That's not going to get anyone competent to bother doing completely useless experiments because you're too lazy to do them yourself.

We're not getting there with the being nice, humble and constructive part I expect. Was tempted to add respect to it but I was glad I didn't. Assumptions and insults won't make a good relation I am afraid. Sorry to have to ignore your further remarks for now...

 

[Arno Fennix]

A nice read: https://www.stereophile.com/content/audioquest-niagara-7000-low-z-power-noise-dissipation-system