Isolation Transformer and Balanced Power versus PS Audio Regenerator

[Amir]

The since discontinued Richard Gray Power Vaults were 11kva units. They are around 1000 pounds and 4’ high - think half of a refrigerator in size - and cost $24k a decade ago when new. It’s a rebadged industrial (hospital use originally) UPS. I use one to bridge between my street feed and my whole home generator. The Power Vault keeps everything stable in between when the power goes out and the external generator kicks in. It feeds a giant Richard Gray transformer, which at some point will get replaced by a Torus unit. GE and Toshiba make similar units.

GE And many UPS/Inverter manufactures changed the design of inverters and now they use transformerless igbt inverters.

I think buying UPS/Inverter from AC power industry is not a good audiograde solution, I think some companies like ASR Emitter or TAD should design a high power AC Regenerator/Inverter.

 

[DasguteOhr]

I had high quality ABB switzerland 20KVa UPS , all of new inverters and UPSs are igbt class d and they shift tonal balance and also decrease sound quality.

We had 10 ×120AH AGM batteries with two Votronic 3KVa sinewave inverters in operation. They worked excellently. However, the load was also small; the sustained load was also less than 1kW.

 

[microstrip]

The most important thing of Balanced isolation transformers is zero leakage current for all audio equipments, when we connect different equipments together each equipment has a chassis voltage (the capacitance between transformer and chassis cause induction voltage) and different voltage is not good for noise level and SNR. When we use balanced power all of these voltages are zero and SNR increase.

Unfortunately it is not so rosy. The primary winding transformers are not symmetrical and most of the mains filters included in equipment are also asymmetrical. There is no "zero" leakage in real world. Some people claim that measuring the leakage voltages at both plug orientations and optimizing their positioning can get better results than using balanced power - it is controversy subject in domestic audio systems, as it introduces a new equipment in series with mains, the balancing transformer. There are no absolutes in this hobby.

 

[microstrip]

It is a fact that we now get power mains from inverters in many places - the alternative energies use inverters to convert DC to AC mains.

 

[Kingrex]

Although balanced output mains transformers can be used for specific, not general use in houses, they need special installation and requirements - it is not a simple DIY affair.

IMO balanced power is only advantageous if the distance between the balancing transformer (or mains board) and system is very large or the system is very complex, self generating a lot of noise.

I have always wondered if Balanced really does much. There is definitely filtration going on with any transformer. I don't know all how they achieve the levels of filtration they get. What I do know is Torus starts around 50K and filter up. I forget where it starts to drop off.
Other filters may start lower. Like 10K or 20K. On the surface that's good in my book. The lower you can go the better?? I don't know what frequency of noise is the most impactful to equipment. Is it Giga, Mega, Kilo hertz. If its not really causing a problem, do you have to address it.

To that point, some gear is a lot better at filtering the power line noise than others. Even so, every filter is heard. So something is going on. Maybe its compressing dynamics and doing something bad. Then you have to ask, why am I making bad in my system. Did I also achieve some level of good? Sometimes a bad filter can be used somewhere else. You really need 3 filters. And they can all be radically different. An Audio Quest 1800 is great on the digital front end. Your modem, router and maybe switch. A shunyata is great on the rack with front end, signal equipment. An isolation transformer is great on most large amps. They are also great on the front end. That is why I lay out designs per post 533. If you invested in power like that, your system would sing. There is more to it. There is the whole grounding, contact enhancers, routing branches to the room. Properly landing duplex. Wire selection. Mains panels.

I had high quality ABB switzerland 20KVa UPS , all of new inverters and UPSs are igbt class d and they shift tonal balance and also decrease sound quality.

Good feedback. There are 2 sets of FET in high frequency inverters. The first set turns the DC to AC. The next set is an amplifier that boost the voltage. Think Exeltech. There are other inverters like Victron and Sonyboy that have a FET to turn the DC to AC, but they use a boost transformer to raise the voltage.
All the powerwalls I have seen use a high frequency inverter. 2 sets of FET. I want to get back out to Mo of Parttime Auidioophile and listen to his Powerwall vs mains power. I think it did soften the dynamics a little. But It was very subtle and hard to tell.

 

[Mike Lavigne]

Although balanced output mains transformers can be used for specific, not general use in houses, they need special installation and requirements - it is not a simple DIY affair.

agree. competent electrical contractors are required, Equi=tech provided good support and install documentation. Equi=tech Balanced Wall Panel systems are common in pro studios. FWIW.

IMO balanced power is only advantageous if the distance between the balancing transformer (or mains board) and system is very large or the system is very complex, self generating a lot of noise.

although i do drink the common mode noise rejection kool aid, i have zero techie understanding and can't defend my 'feelings'.

i only anecdotally hear and appreciate the low noise and dynamics of my own system.

 

[microstrip]

(...) What I do know is Torus starts around 50K and filter up. I forget where it starts to drop off. (...)

In fact, Torus uses a patented system that "filters" much bellow 50k - the Narrow Bandwidth Technology. https://www.toruspower.com/narrow-bandwidth-technology-nbt/ I have researched it some time ago and as far as I can see it, it is an extremely clever system, as it works in parallel with main winding, not in series, as many lower frequency filters. It uses a secondary winding connected to a tuned circuit, removing the distortion and noise from the magnetic core, avoiding increasing the impedance of the mains. Currently I do not have any mains conditioner, but if I could get a Torus to try in my system I would love to do it.

But IMO if we have an open mind the future of power conditioning is in the inverter technique - why repairing the mains when we can have pure mains?

 

[Elliot G.]

GE And many UPS/Inverter manufactures changed the design of inverters and now they use transformerless igbt inverters.

I think buying UPS/Inverter from AC power industry is not a good audiograde solution, I think some companies like ASR Emitter or TAD should design a high power AC Regenerator/Inverter.

There is at least one company I know that makes great power products, complete with science and they are located on the west coast of the USA

 

[Kingrex]

But IMO if we have an open mind the future of power conditioning is in the inverter technique - why repairing the mains when we can have pure mains?

A better pure main power would be a rotary power supply. An electric motor that belt drives an alternator motor. I looked into these too. The hard part is getting a good alternator. The 120 volt models that are greater than 20 amps are almost always 240 volt. And the quality is not real high. They are made to go in portable generators. Then you have to design a safe enclosure to build up the assembly. You also need a speed controller to keep the output stable.

Inverters generally have a pretty high distortion level. Very few are less than 5% Thd. Those that are low distortion, are generally high frequency. The noise is at 20,000 hertz and 100,000 hertz. Low frequency inverters that use a transformer to boost the voltage are generally 10% to 18% thd. Great to drive a pump or AC, but not so good for audio.

I still want to try a Victron inverter. The problem with Inverters, they have a tendency to squeal under load and the fans are noisy. And you also have to device an enclosure to house the duplex. And how do I ship an inverter and battery to a client and have them attach the wiring without shorting something out. That means I have to develop enclosures with a more complex wiring harness.

I am with you in wanting to try battery power. My gut says it could be very good. But my track record show a very good all copper panel in combination with a Torus (or other filter or not) is excellent.

 

[wil]

Mike, which regenerator do you use?

I did not see 10kva regenerator in audio market?

Torus filter corner is around 50,000 herts. Youe power plant is probably switching around 20,000 herts. The fundimental noise would not be changed. But the 3rd and 5th harmonic would be filtered, so it may sound better. You have a Torus, correct? Are you thinking of getting a P20?

What’s the frequency range the Torus filters? 2k to 50k?

If I’m seeing 3rd, 7th and 9th harmonics and presuming a power plant would effectively eliminate those lower harmonics and the Torus would filter above 2k, would the two be seen as complementary?

Or is this thinking too simplistic?

 

[Kingrex]

What’s the frequency range the Torus filters? 2k to 50k?

If I’m seeing 3rd, 7th and 9th harmonics and presuming a power plant would effectively eliminate those lower harmonics and the Torus would filter above 2k, would the two be seen as complementary?

Or is this thinking too simplistic?

What I am told is:
The corner frequency is around 3 to 4 kHz and attenuation rate around 10db/dec. So at 25 kHz attenuation is around 8 db. That would not eliminate a 25kHz noise, but we would make it somewhat quieter.

 

[treitz3]

This may be an unpopular opinion, but no A/C regenerator, nor isolation x-nsfrmr eliminates all of the noise. This is based upon experience.

Tom

 

[Mike Lavigne]

This may be an unpopular opinion, but no A/C regenerator, nor isolation x-nsfrmr eliminates all of the noise. This is based upon experience.

Tom

even batteries have noise and grounding challenges. music reproduction is about real world signal to noise. and how much music can be heard into the noise floor in the gear and media. so lowering noise is only one side of it.

ambient and ground noise can dilute power grid noise efforts. all three need attention.

noise (non musical sound energy) is a part of what we hear even if it's not evident. many times the only way to know about it is when it's gone or reduced. and we might not realize it's due to lowered noise.

and sometimes more noise is musically better. or not clearly worse.

noise needs to be navigated and managed.

 

[Another Johnson]

This may be an unpopular opinion, but no A/C regenerator, nor isolation x-nsfrmr eliminates all of the noise. This is based upon experience.

Tom

This may be true, but my experience is that it depends on what gear you’re trying to power.

Just taking four examples from my experience … the P20 really improved the noise floor on my ARC tube amps, it had no effect on my Home Theater Denon receiver, and it genuinely exacerbated the noise problems I had with my CJ LP275Ms.

I am very happy with it powering my Burmester 911 mk3. Is my noise floor as low as it could be? I don’t know. What I do know is that in very impressive demos of other amps at serious dealers who use other schemes, I return home and do not sense that my system is less clear.

FWIW, I’m using the P20 in my main system to power my Burmester 088/911 mk3 and digital sources. I am using a P12 to power my ARC Ref Phono 3 and my turntables, all located remotely from the main gear. I couldn’t be happier after fighting noise for years.

 

[treitz3]

This may be true, but my experience is that it depends on what gear you’re trying to power.

Agreed, but it still doesn't eliminate all noise.

Tom

 

[Another Johnson]

Agreed, but it still doesn't eliminate all noise.

Tom

Do you really believe that you can eliminate all the noise? I do not. All you can do is compare where you are to where you were.

If you have achieved a noise level where you’ve never heard another system that was better to your ears, it is a good stopping point. When you can no longer say that, then you have to decide whether it’s worth the trouble and cost to make changes.

 

[treitz3]

I do not believe that we have achieved eliminating "all" noise yet. There are so many factors, variations and scenarios, that what works for one, may not necessarily work for another.

As for stopping? Heck no, man. Keep pushing the envelope! Never stop.

Tom

 

[Amir]

when you buy ferrari then everything is ready for enjoyment.

The audio industry is awful because when you buy one million audio system there is no enjoyment and you should put huge amount of time and effort into controlling noise, finding best speaker position, finally most digital records are awful, most modern systems are compressed, ….

I am electronics engineer and I spend more than 20,000 hours since 2000 for audio.

I think climbing K2 in winter is more easy than doing high end.

 

[Alrainbow]

Amir have you measured the effects of noise on dc outputs on power supplies in audio ?

 

[Amir]

Amir have you measured the effects of noise on dc outputs on power supplies in audio ?

No but my ears receive awful distorion of ac power 24/7.