The Truth About HiFi Amplifier Power Supplies

[atmasphere]

Those who may decide to finger them and splice things together without enough knowledge, deserve what comes to them!

Of course! But the likelihood that the manufacturer will get blamed anyway is still there.

 

[egellings]

And for competently designed amplifiers, those line voltage variations, if not excessive (say, from an emergency gas-powered generator) will not affect sound quality at normal listening levels. Those super high gauge expensive power cords are silly, what with all the small gauge house wiring leading up to them. It's like having a wimpy chain with one really good, strong link in it. That link will do nothing for that whole chain at all.

 

[r042wal]

View attachment 234131

Carver PM-2400 (Dual 1200 watt stereo amps in a single chassis). No empty real estate here.

I had one of these before I got my mac. Too bad the fan is so noisy. It sure put out!

 

[DonH56]

I simulated current bandwidth ages ago: https://www.whatsbestforum.com/threads/power-supply-bandwidth.15198/#post-275474 -- have not updated and ported over here, think I decided not worth the effort. But when I click on the pictures "over there" to make them large enough to see I get a "not found" warning. I'll have to dig up the originals sometime.

However, the results are in line with what @solderdude showed, natch, so nothing really new or worthwhile. It was to show that power cord bandwidth for current needs to be a couple orders of magnitude greater than just 50/60 Hz, but not a MHz -- at least for a conventional supply. I don't have data for a SMPS; that might be interesting. Be nice to repeat on a Hypex or whatever class-D amp wall input and see.

 

[atmasphere]

And for competently designed amplifiers, those line voltage variations, if not excessive (say, from an emergency gas-powered generator) will not affect sound quality at normal listening levels. Those super high gauge expensive power cords are silly, what with all the small gauge house wiring leading up to them. It's like having a wimpy chain with one really good, strong link in it. That link will do nothing for that whole chain at all.

A lot depends on what is meant by 'competent'

 

[egellings]

I 'spoze. I generally mean low distortion, low output Z, high input Z, low noise, and adequate power output. Good looks and ergonomics are added pluses. Something like the current Benchmark model comes to mind.

 

[r042wal]

Let’s be clear, the “high-end” mains cable has to perform its magic through a single filament of wire 0.2mm in diameter.

One of my biggest disappointments since my introduction to 'the communities' is how gullible and easily misled audiophiles are. I read the communities and respect some of the valuable opinions until I run across ridiculous posts about fuses and cables either either being directional or needing break-in periods. It is very difficult to shut up and not show these people with theory how misguided how poorly misinformed they and their 'golden ears' are.

One of my biggest peeves is power conditions. I come from a world with 25 years of IT experience dealing with a/c power issues on servers far more demanding and critical than anything you will find in the audio spectrum. Audio equipment runs on DC and doesn't give a chit about AC after it had been rectified, filtered and regulated. Why do you think high-end amp manufacturers like Bryston and McIntosh suggest plugging directly into the wall? A properly designed amp already has this conditioning build in and all these pricy power cords do nothing for the a/c wiring in the wall on the other side of the receptacle or for that matter, when it reaches the 'purple fuse'.

I am reading a book (no name mentioned) about a celebrity, hi-end manufacturer and his struggle breaking into the market of hi-end audio and audiophiles. There is a direct and clear correlation between the thinking of this person in the 1970s and how much of his train of thinking spills over to today where profit, market share, appeal, and hyperbole are just as important today and it was 50 years ago,

 

[Geert]

and as I mentioned earlier a chunky cable, with factory plug and bolted to the inside terminals, should give ideal arrangement for high current situations, probably why we see them in fridges

I prefer a fridge that allows me to switch power cords so I can tune the taste of the food to my liking.

 

[JayGilb]

I prefer a fridge that allows me to switch power cords so I can tune the taste of the food to my liking.

Ha! - If that ever happens, and it could in this crazy world, the reviews would be very interesting.

 

[atmasphere]

One of my biggest disappointments since my introduction to 'the communities' is how gullible and easily misled audiophiles are. I read the communities and respect some of the valuable opinions until I run across ridiculous posts about fuses and cables either either being directional or needing break-in periods. It is very difficult to shut up and not show these people with theory how misguided how poorly misinformed they and their 'golden ears' are.

One of my biggest peeves is power conditions. I come from a world with 25 years of IT experience dealing with a/c power issues on servers far more demanding and critical than anything you will find in the audio spectrum. Audio equipment runs on DC and doesn't give a chit about AC after it had been rectified, filtered and regulated. Why do you think high-end amp manufacturers like Bryston and McIntosh suggest plugging directly into the wall? A properly designed amp already has this conditioning build in and all these pricy power cords do nothing for the a/c wiring in the wall on the other side of the receptacle or for that matter, when it reaches the 'purple fuse'.

I am reading a book (no name mentioned) about a celebrity, hi-end manufacturer and his struggle breaking into the market of hi-end audio and audiophiles. There is a direct and clear correlation between the thinking of this person in the 1970s and how much of his train of thinking spills over to today where profit, market share, appeal, and hyperbole are just as important today and it was 50 years ago,

Most of the power conditioners you see used in audio, both in 'high end' and the pro world, in word, suck.

Elgar made some great power conditioners which could provide a sine wave of less than 0.5% THD with regulated line voltage without current limiting up to their rated VA (some of which could do 5000VA). These are older units and likely need refurbishment prior to use. For equipment that lacks feedback or has limited feedback ( Less then 30dB which includes most solid state amps made prior to 20 years ago) this can be a real boon. It is the 5th harmonic that seems to cause a lot of problems for power transformers (see Fluke Instruments for more information on this); its the mark of a good conditioner if it can filter the 5th out. The newer PS Audio conditioners seem to work quite well but are expensive- you can do as well or better with the Elgars, although they have a noisy cooling fan and have an industrial appearance. But they are built for 24/7 service so are best used wired into the home's wiring by the breaker box, since they are large enough to handle some of the biggest audio amps made.

Self oscillating class D amps can have enough feedback that you can really bypass most of this unless your area is prone to brown outs.

 

[solderdude]

The Elgars were indeed really good and actual regenerators and could be isolated from mains which could be an advantage.

The current PSAudio thingies are not (the early ones were). They 'add/subtract' a small signal to the incoming mains which 'repairs' the waveform.
An advantage is they are sync'd to mains and efficiency is higher, a disadvantage is that the output is not isolated from mains and it relies on a common mode filter on the input and does not break ground loops.

It falls under the category 'most' (see below)

Most of the power conditioners you see used in audio, both in 'high end' and the pro world, in word, suck

The UPS (battery fed) for computers usually do not have a nice sine-wave, nor is that needed in most cases as they are designed to power computers/servers etc.

 

[egellings]

One of my biggest disappointments since my introduction to 'the communities' is how gullible and easily misled audiophiles are. I read the communities and respect some of the valuable opinions until I run across ridiculous posts about fuses and cables either either being directional or needing break-in periods. It is very difficult to shut up and not show these people with theory how misguided how poorly misinformed they and their 'golden ears' are.

One of my biggest peeves is power conditions. I come from a world with 25 years of IT experience dealing with a/c power issues on servers far more demanding and critical than anything you will find in the audio spectrum. Audio equipment runs on DC and doesn't give a chit about AC after it had been rectified, filtered and regulated. Why do you think high-end amp manufacturers like Bryston and McIntosh suggest plugging directly into the wall? A properly designed amp already has this conditioning build in and all these pricy power cords do nothing for the a/c wiring in the wall on the other side of the receptacle or for that matter, when it reaches the 'purple fuse'.

I am reading a book (no name mentioned) about a celebrity, hi-end manufacturer and his struggle breaking into the market of hi-end audio and audiophiles. There is a direct and clear correlation between the thinking of this person in the 1970s and how much of his train of thinking spills over to today where profit, market share, appeal, and hyperbole are just as important today and it was 50 years ago,

The cable and fuse baloney is based on belief, not knowledge. You can edit/update knowledge when necessary, but belief is read-only.

 

[r042wal]

When I was in IT I used a particular Tripp-Lite model that wan the DC inverter off the batteries and there was no connection to the AC side other than

The cable and fuse baloney is based on belief, not knowledge. You can edit/update knowledge when necessary, but belief is read-only.

LMFAO

 

[DonH56]

The UPS (battery fed) for computers usually do not have a nice sine-wave, nor is that needed in most cases as they are designed to power computers/servers etc.

Note most all consumer UPS units are off-line types so the only time they are actually delivering power to the load is when the wall power is off. The rest of the time wall power just passes through, sometimes with a little filtering and/or surge suppression. The only time they are sending "dirty" power is when they are running, which in my case is just long enough for me to turn things off cleanly. I have had to correct a few friends who bought into the ugly marketing pictures of stepped-sine approximations and thought that was what it was providing all the time. Nope.

Lately I have been buying more "pure sine" UPS units that are a bit cleaner, though nothing to write home about, For that matter the voltage from the wall is not all that clean to begin with. But the vast majority of components have excellent power line noise rejection so do not care.

 

[solderdude]

Yes, I should have said in-line UPS ...

 

[atmasphere]

The Elgars were indeed really good and actual regenerators and could be isolated from mains which could be an advantage.

The current PSAudio thingies are not (the early ones were). They 'add/subtract' a small signal to the incoming mains which 'repairs' the waveform.
An advantage is they are sync'd to mains and efficiency is higher, a disadvantage is that the output is not isolated from mains and it relies on a common mode filter on the input and does not break ground loops.

It falls under the category 'most' (see below)

The Elgars I've seen were not regenerators. I've seen two variants, one which uses a large autoformer and the other an isolation transformer. Otherwise the operation is the same: a low distortion oscillator puts out a 60Hz sine which is synchronously locked to the line frequency. To maintain the sync a 60Hz resonant circuit is used. The output of the oscillator is compared to the output of the main transformer creating a feedback signal. A difference amplifier applies the feedback signal to a power amplifier which simultaneously bucks the output voltage up or down as needed while it applies the feedback signal at the same time to the transformer. The power amplifier has its own power supply running off the mains transformer. The fan is for the power amplifier which is an AB linear circuit. I've been thinking that a class D amp could do the job better, perhaps eliminating the need for the fan. But I don't have much impetus since the amps and preamps in my system are pretty well immune to AC power problems.

 

[r042wal]

I used pure sine wave Tripp-Lite server UPSs in my customers server rooms. I was told the AC inverter ran off the battery in the UPS and there was no bridge to the incoming AC. Does that sound reasonable?

Going back to my original post, I am not knocking using a UPS in your system but I feel the propeller heads get a little carried away with great claims of improved sound, stage presence and all the other audiofool terms that 'golden ears' seem to have. I am not sure what the other guy sells his power regenerators for but if it was around $6000, you can buy several pure sign wave UPSs for that kind of money and they would likely perform better too.

 

[solderdude]

The Elgars I've seen were not regenerators. I've seen two variants, one which uses a large autoformer and the other an isolation transformer. Otherwise the operation is the same: a low distortion oscillator puts out a 60Hz sine which is synchronously locked to the line frequency. To maintain the sync a 60Hz resonant circuit is used. The output of the oscillator is compared to the output of the main transformer creating a feedback signal. A difference amplifier applies the feedback signal to a power amplifier which simultaneously bucks the output voltage up or down as needed while it applies the feedback signal at the same time to the transformer. The power amplifier has its own power supply running off the mains transformer. The fan is for the power amplifier which is an AB linear circuit. I've been thinking that a class D amp could do the job better, perhaps eliminating the need for the fan. But I don't have much impetus since the amps and preamps in my system are pretty well immune to AC power problems.

The Elgar 751SL (2kW) , 1001SL (2.8kW) and 1751SL(5kW) were variable AC power supplies that could put out a frequency between 45Hz and 5kHz.
Thus the generated AC power from scratch (AC in -> DC -> AC) so were 'regenerators' but were not sync'd to mains but could do this with an additional card.
No batteries inside.

 

[DonH56]

Is Sola still around? Didn't they make resonant transformers? Not that an audio component needs one...

 

[atmasphere]

The Elgar 751SL (2kW) , 1001SL (2.8kW) and 1751SL(5kW) were variable AC power supplies that could put out a frequency between 45Hz and 5kHz.
Thus the generated AC power from scratch (AC in -> DC -> AC) so were 'regenerators' but were not sync'd to mains but could do this with an additional card.
No batteries inside.

I was not talking about their later stuff, which I think they identify as 'AC power sources' rather than conditioners. Some of those are quite good and could be used as a conditioner; certainly better than the junk that pervades high end audio. I was talking about the 3000, 6000 and 7000 series.