Discussion of AC mains isolation transformers

[flkin]

On 1/25/2024 at 2:30 PM, flkin said:

 

I reached out to Vladimir Kraz from OnFilter and he had the following to say comparing their CleanSweep to an IT.

 

" ...I am not a big fan of transformers - first, they have relatively high output impedance (magnetic coupling + windings); they don't do anything for differential mode (i.e. between Live and Neutral); they have EMI leakage via parasitic capacitance between the winding; they have their own resonances...

.. IT won't do is to filter ground noise which our filters do very well (it is our patented feature). "

 

He further says :

 

" that in It would explain why regular EMI filters and transformers may work well for formal compliance (CE) but in the field they may not do such a good job. "

 

To be complete, Vladimir Kraz doesn't claim the CleanSweep is any good for audio purposes but for industrial purposes it does the job it's designed for. He also included an article he wrote about ELECTROMAGNETIC COMPLIANCE: A VIEW FROM THE FIELD for inCompliance Magazine which identifies the issues he faced in a factory setting. Worth reading.

 

On 1/25/2024 at 10:35 PM, Rsbrsvp said:

...

I want to try the cleensweep but I live in Israel and shipping and duties is not doable for me.

 

I went for the Online CleanSweep industrial device and it's been in my system for few weeks now. In a nutshell it works for audio and has replaced my Topaz. 

 

I have it from wall to CleanSweep to the system except for power amps. System includes pre-amp/DAC, streamer and a DC power supply feeding the router and USB card inside the streamer. For power amps I still have them direct to wall through a Shunyata Hydra 8 as before. In this configuration I am getting more details with cleaner edges. More accurate tones.

 

I'll do a proper writeup when I get some time. A lot of details to share like using it alongside the Topaz, placing it on different devices separately, effect on my power amps, EMI measurements using a line meter etc.

 

This is just a quick nod for the CleanSweep and to thank @Rsbrsvp for bringing it to my attention.

[Rsbrsvp]

2 hours ago, flkin said:

 

 

I went for the Online CleanSweep industrial device and it's been in my system for few weeks now. In a nutshell it works for audio and has replaced my Topaz. 

 

I have it from wall to CleanSweep to the system except for power amps. System includes pre-amp/DAC, streamer and a DC power supply feeding the router and USB card inside the streamer. For power amps I still have them direct to wall through a Shunyata Hydra 8 as before. In this configuration I am getting more details with cleaner edges. More accurate tones.

 

I'll do a proper writeup when I get some time. A lot of details to share like using it alongside the Topaz, placing it on different devices separately, effect on my power amps, EMI measurements using a line meter etc.

 

This is just a quick nod for the CleanSweep and to thank @Rsbrsvp for bringing it to my attention.

Thanks for the update.   I'm hoping to order mine too.    I will be curious about EMI measurements- but truth is- not everything is EMI.  Isolation, grounding, leakage, impedence, and all this other technical stuff I dont understand seems to make a difference.  What matters is what sounds better at the end of the day.  I am not a scientist, but rather an audiophile.

[Rsbrsvp]

FLkin,

 

Does the Cleansweek onfilter make the sound thin or bright?  Is the sound as tonally dense as when using the Topaz?

[flkin]

5 hours ago, Rsbrsvp said:

FLkin,

 

Does the Cleansweek onfilter make the sound thin or bright?  Is the sound as tonally dense as when using the Topaz?

 

No reduction in density or sound stage size. Only when used with my power amps there was a reduction in size, thinner and smaller. Almost like needing more volume.

 

But without the power amps attached, there was just more info in the music, ambient sounds clearer, enunciation of vocals with better finishing or "tail". Tonally a touch brighter but in my system perhaps more accurate? Piano sounds more bell like at the upper end which is what I was trying to get to.

 

My 1000W Topaz was only used to power the 2 rails of my DC supply to my router and USB card so it's not a direct comparison. In the past, I couldn't get better results with other components attached.

 

[flkin]

20 hours ago, Rsbrsvp said:

Thanks for the update.   I'm hoping to order mine too.    I will be curious about EMI measurements- but truth is- not everything is EMI.  Isolation, grounding, leakage, impedence, and all this other technical stuff I dont understand seems to make a difference.  What matters is what sounds better at the end of the day.  I am not a scientist, but rather an audiophile.

 

I believe most of us here are audiophiles in the way you suggest. Just that this CleanSweep is an industrial device designed to remove EMI from the AC line so it does claim to do something that can be measured. I happen to have line and air EMI measuring devices purchased a long time ago and so checking that the CleanSweep actually does its job (and not just a black box :D) was easy. More info later but quickly the Topaz output measures better than the CleanSweep as per my AlphaLab Line EMI meter on the Live-Neutral lines. I too dont rely on numbers for hifi decisions and prefer to follow my ears when it comes to choices. 

[Rsbrsvp]

So- I wrote to Mike Lester of Puritan Audio.   Anyone who searches the internet will see the nearly unanimous praise on head-fi, audiocircle, audiogon, etc regarding his PSM156 mains filter.  I say nearly unanimous because around 10% of reports complain his mains conditioner makes the sound thin or bright.  Perhaps another roughly 10% say it is a subtle change for the good and around roughly 80% say the change is substantially for the good.  Please check yourselves.   He is a genius in the field whether one likes his way of doing things or not.  His filters are so popular, he cannot make them as fast as he sells them.  He is literally inundated...

I wrote to him to ask if his conditioner raises impedance and if that is a problem and he basically answered "yes" without saying so literally.  He said anything you put between your wall and your component damages the sound.  The goal is to come up with a device which improves sound more than it damages.  He also said EMI is easy to get rid of.  He could have designed his units to remove much much more EMI than they do easily- but the problem is the damage that results from this process becomes more than the value of removing the EMI.  So- I am attaching his letter as a lesson to us. 

 

___________________________________________________________________________________________________________________________________________________

 

The only truly relevant measurement is with the instruments each side of your head.

 

We do not publish detailed blueprints of measurements,  materials, methods or other design aspects. This is hard earned knowledge that we accumulate and apply towards a better sound.

 

The thing with conditioners is that they can do as much harm as good and balance is critical:

 

Anything in between the mains wall socket and the power input of the equipment is going to be bad, even a just few centimetres of cable will have a resistance to current flow and an eagerness  to act as an antennae gathering interference, both bad.

 

But, the state of pollution of mains electricity worldwide is awful and this is something which has crept up on us massively over the last few decades with now very often in excess of a volt, sometimes several,  of high frequency hash carried on top of the legitimate voltage waveform. And this is really, really bad for trying to resolve every subtle nuance, phasing and clue from a musical presentation.

 

We quickly discovered, because we listen intensively to every step we take,  that that achieving more decibels of  noise reduction for the spec sheet was very  easy but definitely not desirable:

 

We noted  that taking away HF hash liberated electronics. By not having signals blurred, smeared and buried and not having  processes  swamped by supersonic garbage, then being able to concentrate solely on  those signals you want;  not only source components but amps as well benefited,  greatly  increasing dynamics,  broadening and giving greater depth to the sound stage and definition…….. But go over a line and you go backwards  flattening the image and draining the life.

 

This circles back to my earlier comment that introducing anything in the power line introduces a restriction = bad. With power conditioning you are inserting elements to eliminate the HF noise  but which by their nature will also have a negative side.

 

We went to enormous lengths to correctly identify  the sweet spot of just enough cleansing but not too much,  but this was not quite so easy as the sweet spot had to hold for a host of very different loads;   sources and amps alike, amps of low power through to high power  and  Classes  A through  to D. After a very long time with hundreds of adjustments to a series of potential  prototypes in countless different audio set ups we arrived at our solution of which we are extremely proud.

 

The PSM156 (and PSM1512) work by having the  optimum degree of noise filtration,  also  taking care of star grounding, DC offset , surge protection and importantly isolating  each connected component from each other so that cross contamination cannot occur.  We think we nailed it.

 

Best wishes – Mike

[Rsbrsvp]

Flkin,  have you tried using the Topaz and the onfilter togethee?

 

If so- how does it sound?

[flkin]

@Rsbrsvp, my listening notes has this :

 

1. Streamer, Pre and DC Power Supply to both USB and Router on CleanSweep and add Topaz before only the DC power supply.

- Slightly thinner and more treble weighted. Only very slightly.

 

2. Streamer, DC Power Supply and Pre on CleanSweep. Add Topaz before preamp

Initially:

- Vocals, full of inflections and breath control artifacts

- Zero treble hardness or emphasis. Correct balance.

- Transparency up a notch. Texture of piano step closer to real. Weight of notes, bell sound of Steinway

Later:

- Too clear and over tight? Maybe need a bit more relaxed?

- Returned to without Topaz, only the CleanSweep. Yes better size and expanded. More relaxed but still with full details.

 

Removed the CleanSweep 5 days later to confirm the drop in performance. Listening notes say this :

 

CleanSweep makes edges clearer. Tone brighter but more accurate - piano has a more bell like sound. More details. Hammer and pedal sustain action (in piano pieces) clearer. Squeak string sound from slow pedal action on uneven piano strings is so clear.

 

Overall, I think the streamer, pre and DC supply to USB and Router alone through the CleanSweep sound best in my setup. I think if I had to summarise, the action of reducing noise seems to clean up the sound, make details pop. Over cleaning, like putting 2 strong cleaners in series, might thin out the sound and affect treble the balance and weight of sound. I guess from the effects of added impedance? How much to clean would probably depend on how dirty the AC was in the first place, there may not be a clear answer applicable to all systems.

 

Soon after this conclusion, as I was dressing my cables, I had an accident where my RCA cable was partially unplugged when I switched on my very powerful monoblock amps. A huge bang occured not unlike a canon going off and it damaged the voice coil of my Wilson mid driver. No further tests possible but I had reached a conclusion prior to the accident anyway. But once my Watt speakers are back in action, it will sound pretty different as I had many other parts updated like tweeter surrounds and the resistors inside. How I prefer the CleanSweep setup might change after this.

 

 

[Rsbrsvp]

Flkin,

 

I appreciate this and it fits my experiences with mains conditioners.

 

My PSM156, like the cleensweep makes things brighter and leaner.  Is it a bad brightness?  Depends on the system and the ears.

 

The amount of clarity, seperation, detail, crispness it allows through is way above the Topaz .0005 isolation transformer I have, but it is thinner sounding and brighter.   In the wrong system- the PSM156 can be to much of a good thing; to much filtering- and end up with unpleasant results.  The Topaz is to my ears revealing much less of the good which the PSM156 does, but still some of it, and with none of the bad.  In other words, the music remains sonically dense and tonally darker, rounder- which to my ears is preferable in general.  

 

I am convinced, seperate of numbers, measurements,  or any technical understanding, that the PSM156 is filtering much more noise than the Topaz- and no measuring device will change my mind.  Less noise equals more detail, transparency, seperation, crispness, authority;- and the PSM156 results in substantially more positives in these descriptors.  More detail also usually results in leaner, drier, sharper sound- perhaps not so positive if overdone.

 

One nice option for me is to combine.  I put my digital equipment on the PSM156 where I feel the benifits are greatest and the negitives are least and the Topaz on my preamp and amplifier to keep things thicker and rounder as I feel the PSM overdoes the cleanning process on the analogue section IMHO while the Topaz has it right on this equipment.  Its all a game and everyone will come to their own conclusions.