Isolation Transformer and Balanced Power versus PS Audio Regenerator

[microstrip]

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

It is possible and easy to have noiseless AC mains if we objectively specify what is meant by "all of the noise" in electrical terms. Surely if people specify noise using their ears it is a lost cause ...

We should remember two aspects 1. Every piece of equipment generates specific noise that can flow through the power wires to other equipment and we sometimes want our power device to absorb this noise and 2. Some people praise and buy controlled noise sources to tailor the sound of their systems. Surely most call them "noise absorbers" or similar for marketing purposes.

 

[wil]

It would be interesting see what kind of harmonic distortion you have from your utility , and a picture of your voltage waveform.

 

[wil]

It is possible and easy to have noiseless AC mains if we objectively specify what is meant by "all of the noise" in electrical terms. Surely if people specify noise using their ears it is a lost cause ...

We should remember two aspects 1. Every piece of equipment generates specific noise that can flow through the power wires to other equipment and we sometimes want our power device to absorb this noise and 2. Some people praise and buy controlled noise sources to tailor the sound of their systems. Surely most call them "noise absorbers" or similar for marketing purposes.

@microstrip, what is your opinion, theoretically, of using a PS Audio power plant before a Torus (rm20) to address harmonics/noise at different frequency ranges?

 

[Amir]

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

Which company?

 

[microstrip]

@microstrip, what is your opinion, theoretically, of using a PS Audio power plant before a Torus (rm20) to address harmonics/noise at different frequency ranges?

As far I have measured it - just the P10, not the P20 - you will not need a Torus to remove harmonics after the P10 - it is extremely low distortion. The effective real distortion will surely depend on the load you put on the regenerator or transformer.

 

[microstrip]

It would be interesting see what kind of harmonic distortion you have from your utility , and a picture of your voltage waveform.

I have posted if before, unfortunately I do not have an accessible spectra now. Anyone can do it easily using free software, a decent usb sound card and a few extra parts. The mains frequency and harmonics are in the audio band!

 

[Amir]

As far I have measured it - just the P10, not the P20 - you will not need a Torus to remove harmonics after the P10 - it is extremely low distortion. The effective real distortion will surely depend on the load you put on the regenerator or transformer.

Line, Neutral and earth all of three are important and even one of those can damage the sound.

it means if you use isolation transformer (isolate both line and neutral) then dirty earth can damage the sound. If you use ps audio p20 then both neutral and earth can damage the sound.

I asked Paul and he said p20 does isolate neutral.



My ABB UPS distortion was low but the sound was not good, this subject is very complex.


perfect solution for AC regeneration is my dream

 

[Folsom]

The biggest impact I've ever heard on swapping a power cable was going from the wall to a regenerator. I don't think any of them are pure in any real sense of what you'll experience. (It was a PS unit)

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.

I doubt those are very clean. The power you get from the utility company starts at a lower voltage then is converted to a higher one with probably somewhat leaky transformers outside of 50/60hz. Then it travels over high resistance until it arrives and the voltage is turned down to house level by another transformer that may be mildly leaky. So noise goes up potentially in voltage but over a lot of resistance and then converted to house voltage so all but one step for sure reduces noise and one is a maybe. It's actually a fairly smart system. But as far as alternators being not noisy themselves, they don't have any of these benefits. The armature is likely not perfect and there are probably a fair bit of other currents happening, but there is no inherit system that reduces them. My guess is it'll be disappointing. But using 240v and turning it down to 120v would at least give you a mild reduction in the noise you're making. In general I doubt it can meet demand without being grossly oversized (which also introduces issues).

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.

The balanced transformer itself is ideally leaky so it doesn't add differential noise - by acting like an isolation transformer where leakage is essentially equal to filtration.

It is possible and easy to have noiseless AC mains if we objectively specify what is meant by "all of the noise" in electrical terms. Surely if people specify noise using their ears it is a lost cause ...

We should remember two aspects 1. Every piece of equipment generates specific noise that can flow through the power wires to other equipment and we sometimes want our power device to absorb this noise and 2. Some people praise and buy controlled noise sources to tailor the sound of their systems. Surely most call them "noise absorbers" or similar for marketing purposes.

Amen. What people think they hear and what is really going on is often unrelated, and there's a ton of noise generator/collectors on the market. The quickest example would be that bass isn't the first place you hear a lack of current even if the measurement is potentially showing it. In fact improved impedance can often reduce bass in solid state equipment.

 

[wil]

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

Amir, If this the case I would think you would want to have some information about your mains power. Such as: Ground resistance; Voltage stability; Voltage sinewave, harmonic distortion…

How can you hope to have a good sounding system without addressing what you hear as “awful distortion of ac power”?

 

[Amir]

Amir, If this the case I would think you would want to have some information about your mains power. Such as: Ground resistance; Voltage stability; Voltage sinewave, harmonic distortion…

How can you hope to have a good sounding system without addressing what you hear as “awful distortion of ac power”?

In Iranian new year holiday (21 march - 2 April) I have very good AC power quality but after that the ac power quality is not good most of the time. I can say saturday is better than other days of week.

Actually many audiophiles around the world have ac power quality problem but their audio system does not reveal it so much or they use filters that control the noise.

I think TAD Reference is one of the most revealing audio system in the world and the TAD easily shows contrsat between AC power quality, CD quality records, different cables …

I can use big isolation transformer or some filters but finally I do not like dynamic compression.

 

[Kingrex]

In Iranian new year holiday (21 march - 2 April) I have very good AC power quality but after that the ac power quality is not good most of the time. I can say saturday is better than other days of week.

Actually many audiophiles around the world have ac power quality problem but their audio system does not reveal it so much or they use filters that control the noise.

I think TAD Reference is one of the most revealing audio system in the world and the TAD easily shows contrsat between AC power quality, CD quality records, different cables …

I can use big isolation transformer or some filters but finally I do not like dynamic compression.

Have you tried a 10kva Torus? Don't use it on everything if you think your equipment is that sensitive. Start with just the amps. Or the front end. Id you like it, I'm sure they would welcome you as a dealer.

Throw away any power device in your electrical distribution that is in line with the audio system. Dexit DN5S every contact in your power panel. The Line and load to every breaker and the neutral and ground bars. Remove any neutral or ground that is not copper and replace with copper. Make sure all comb bus are copper. Once the panel is done, do every duplex in the audio room. Where the branch wire terminates to the duplex, as well as the duplex prongs themselves. If you are using new breakers, fresh stripped wire or duplex, use GN5S.

 

[Kingrex]

Throw away was the wrong phrase. Replace with new if older than 5 years.

 

[microstrip]

(...) I think TAD Reference is one of the most revealing audio system in the world and the TAD easily shows contrsat between AC power quality, CD quality records, different cables … (...)

People can also say so that gear whose sound quality depends excessively on mains quality is poorly designed. A good designer can produce equipment that rejects mains distortion and noise.

 

[Folsom]

People can also say so that gear whose sound quality depends excessively on mains quality is poorly designed. A good designer can produce equipment that rejects mains distortion and noise.

That depends a bit on what gear, and how you define the quality of it. For a lot of it this is very true, but not everything is black and white when you have specific sonic intentions.

Feedback or a lack thereof can present other situations. Tube designers often reduce noise with extremely big chokes but those have their own flavor. If you don't like the flavor of the chokes your options to negate noise become hampered a fair bit so you may end up with trade offs.

 

[Kingrex]

That depends a bit on what gear, and how you define the quality of it. For a lot of it this is very true, but not everything is black and white when you have specific sonic intentions.

Feedback or a lack thereof can present other situations. Tube designers often reduce noise with extremely big chokes but those have their own flavor. If you don't like the flavor of the chokes your options to negate noise become hampered a fair bit so you may end up with trade offs.

Scott who made my amps said something similar to me once. As you clamp noise, you loose some of the magic.

I love my Channel D Lino phono stage. Its very quiet and extremely good at rejecting noise. But I have played it head to head with a Sutherland Loco that is a similar design. The Loco is better sounding. But, the Loco has noise issues. In the wrong room, you just have to return it and use something else.
That situation is not something any filtet will fix. Maybe a faraday cage. But I hear even those can impart a sound.

 

[wil]

Measurements of P20 from a review in hifi-news:

PS Audio DirectStream Power Plant P20 Mains Generator Lab Report​

Lab Report
Testing mains regenerators falls outside the normal run of HFN lab reports so I've built some special equipment to do so. The first uses an inline Hall-effect current transducer from LEM Components that can record currents of up to 80A at slew rates of greater than 60A/μs over a bandwidth exceeding 100kHz, while adding a series resistance of only 0.18mohm. Built into a box with flying leads terminated in a mains plug at one side and a mains socket at the other, it can be inserted in the mains feed to any component to measure mains charging current.
Tested by powering-up a Naim Audio NAP 300 amplifier, itself outputting 85W continuous on each channel into a 4ohm load, the charging current waveform from the wall socket [red trace, Graph 1 below] is significantly improved by the P20 [black trace]. The P20's current pulses are almost textbook whereas those from the wall socket have a lower peak value and longer duration as a consequence of the mains waveform being flat-topped and the source resistance being higher.

Distorted mains (charging) current waveform (red) versus significantly more linear waveform delivered by the PS Audio DS Power Plant P20 (black).

Mains voltage waveform, from wall socket (red) vs P20 in Sine mode (black) and MultiWave (blue)


Distortion measurements must accommodate mains regenerators that have unbalanced, balanced or floating outputs, for which I've built a balanced resistive attenuator that feeds an INA217 low-noise, low-distortion instrumentation amplifier. Together these give a voltage output one-hundredth that of the difference between the live and neutral lines, with much lower inherent distortion than a transformer-based solution. Once again, obvious differences are seen between the voltage waveforms from the wall socket [red trace, Graph 2], the P20 on its low distortion sine wave output [black trace, Graph 2] and on the highest MultiWave setting [green trace, Graph 2]. The test table lists individual amplitudes of the first four odd harmonics (each referenced to the 50Hz fundamental) plus a THD figure calculated from the first 14 harmonics. While the P20 correctly reported output distortion as 0.1% on sine wave, it still said 0.1% with MultiWave output selected. KH

Harmonic	Mains	P20 (Sine)	P20 (MW6)
3rd	-41.1dB	-61.4dB	-21.5dB
5th	-31.4dB	-61.1dB	-62.4dB
7th	-45.7dB	-68.7dB	-71.0dB
9th	-50.8dB	-74.4dB	-73.0dB
THD (2nd-14th)	2.92%	0.14%	8.41%

 

[QuadDiffuser]

Here’s the URL to the review from 5+ years ago: https://www.hifinews.com/content/ps-audio-directstream-power-plant-p20-mains-generator

 

[microstrip]

Measurements of P20 from a review in hifi-news:

PS Audio DirectStream Power Plant P20 Mains Generator Lab Report​

Lab Report
Testing mains regenerators falls outside the normal run of HFN lab reports so I've built some special equipment to do so. The first uses an inline Hall-effect current transducer from LEM Components that can record currents of up to 80A at slew rates of greater than 60A/μs over a bandwidth exceeding 100kHz, while adding a series resistance of only 0.18mohm. Built into a box with flying leads terminated in a mains plug at one side and a mains socket at the other, it can be inserted in the mains feed to any component to measure mains charging current.
Tested by powering-up a Naim Audio NAP 300 amplifier, itself outputting 85W continuous on each channel into a 4ohm load, the charging current waveform from the wall socket [red trace, Graph 1 below] is significantly improved by the P20 [black trace]. The P20's current pulses are almost textbook whereas those from the wall socket have a lower peak value and longer duration as a consequence of the mains waveform being flat-topped and the source resistance being higher.

Distorted mains (charging) current waveform (red) versus significantly more linear waveform delivered by the PS Audio DS Power Plant P20 (black).

Mains voltage waveform, from wall socket (red) vs P20 in Sine mode (black) and MultiWave (blue)


Distortion measurements must accommodate mains regenerators that have unbalanced, balanced or floating outputs, for which I've built a balanced resistive attenuator that feeds an INA217 low-noise, low-distortion instrumentation amplifier. Together these give a voltage output one-hundredth that of the difference between the live and neutral lines, with much lower inherent distortion than a transformer-based solution. Once again, obvious differences are seen between the voltage waveforms from the wall socket [red trace, Graph 2], the P20 on its low distortion sine wave output [black trace, Graph 2] and on the highest MultiWave setting [green trace, Graph 2]. The test table lists individual amplitudes of the first four odd harmonics (each referenced to the 50Hz fundamental) plus a THD figure calculated from the first 14 harmonics. While the P20 correctly reported output distortion as 0.1% on sine wave, it still said 0.1% with MultiWave output selected. KH

Harmonic	Mains	P20 (Sine)	P20 (MW6)
3rd	-41.1dB	-61.4dB	-21.5dB
5th	-31.4dB	-61.1dB	-62.4dB
7th	-45.7dB	-68.7dB	-71.0dB
9th	-50.8dB	-74.4dB	-73.0dB
THD (2nd-14th)	2.92%	0.14%	8.41%

Besides price and weight, my main concern with the P20 is heat - I could not find numbers on its efficiency.

When reading the review we must note that Paul Miller mains has significant 5th harmonic distortion - known to affect sound quality in stereo systems.

From the review "Distortion measurements must accommodate mains regenerators that have unbalanced, balanced or floating outputs, for which I've built a balanced resistive attenuator that feeds an INA217 low-noise, low-distortion instrumentation amplifier. Together these give a voltage output one-hundredth that of the difference between the live and neutral lines, with much lower inherent distortion than a transformer-based solution".

It is the proper way to go, but I still use a transformer-based solution to make my own measurements. I compared it with a resistive divider in a floating arrangement (a dangerous thing to do) and the differences were minimal.

 

[Another Johnson]

When I was using the P20 to power my ARC REF 250SEs and REF 6SE, it was not taxed, but it did put that needle up on the display.

It never got too hot to comfortably touch it. It has serious heat sinks.

Running the Burmester 911 mk3 and 088 is no challenge at all. The power shown on the display stays low most of the time, and it could be classified as not much over room temperature to the touch.

I think Paul McG once said that losses at the P20 were on the order of 20%, but I may not remember this correctly. If you want to know, call PSAudio. My experience is that the phone jockeys may not have an answer … but they will do their best to get you a correct answer. Paul is approachable, and he really wants to support his customers.

Another thought is that when thunderstorms are near my location, the whole system can be turned off with the one P20 button, and the whole system can be removed from the mains by pulling the one P20 cord.

And if you forget, or aren’t home, the P20 will self protect quickly in the event of a lightening event, and in so doing, it provides protection for the gear it is powering.

 

[Amir]

Have you tried a 10kva Torus? Don't use it on everything if you think your equipment is that sensitive. Start with just the amps. Or the front end. Id you like it, I'm sure they would welcome you as a dealer.

Throw away any power device in your electrical distribution that is in line with the audio system. Dexit DN5S every contact in your power panel. The Line and load to every breaker and the neutral and ground bars. Remove any neutral or ground that is not copper and replace with copper. Make sure all comb bus are copper. Once the panel is done, do every duplex in the audio room. Where the branch wire terminates to the duplex, as well as the duplex prongs themselves. If you are using new breakers, fresh stripped wire or duplex, use GN5S.

No but I had 10kva transformer and it was not good for me.

In my system over 80% of AC problem is about digital source, pre and power are less sensitive to ac power quality.

My apartment ac power is three phases , two phases are for home appliances and one phase is dedicated to my audio system.