Good Class D amps ??

[opus101]

13 hours ago, barrows said:

You are making yourself look really bad here.

 

My only disgreement with your points @barrows - this has already been done.

[opus101]

19 minutes ago, firedog said:

He’s simply saying he - and others - can design an SMPS that is quieter and more linear than what those same people regard as audiophile level  linear power supplies. 

 

I don't see anywhere he's talking about linearity of power supplies, seems to me meaningless as power supplies don't amplify signals. He took issue with the terming of 'traditional' mains-frequency transformer power supplies as 'linear' ones that's all.

[Ralf11]

7 hours ago, Ralf11 said:

Would you mind briefly outlining your education and background in science or engineering, @GUTB  ??

 

???

[opus101]

1 minute ago, Ralf11 said:

???

 

To those with an engineering background, its been obvious for quite some time that @GUTB doesn't have one. But that fact is quite irrelevant - what's much more relevant is his apparent imperviousness to correction.

[DancingSea]

How about we drop this pointless feud and return to discussing options for good class D amps?

 

Seems simple enough ???

[esldude]

1 hour ago, monteverdi said:

So what about LPS. There is a general idea that toroids are the best transformers. They were developed for military reasons for saving space in airplanes and because they were fancy and and expensive (not so much anymore) they were the things to put in better audio equipment. What about R-core transformers, much less primary to secondary capacitance and therefore less high frequency noise leakage.

I like that forum to learn and not to preach!

 

Not trying to be cute with you, but any of those methods can be done exceedingly well.  They all have issues to be solved, advantages inherent in the design.  But all have to have the devil in the details beaten out of them to work well.  SMPS too. 

 

In LPS you can have capacitor filtered, choke filtered, and actively regulated just to pick a few broad categories before getting to the xfmrs in use.  You can use big xfmrs for good reason and put them outside the main box for the gear to get hum away from it.  You can do what some aircraft one did run everything at 400 hz so the xfmrs can be much smaller.  

 

The bottom line is any of those can work and work well.  If I tell you I have an SMPS it might be state of the art or it might be a wall-wart radiating garbage in all directions.  Same for the xfmrs types in LPS.  You really can't say, "R-core xfmrs are the only basis for great quiet power supplies."  Or EI core or C core or whatever. 

 

This is not a bad basic explanation of the issue here:

 

http://www.audioxpress.com/article/Power-Transformers-for-Audio-Equipment  

[opus101]

1 hour ago, monteverdi said:

There is a general idea that toroids are the best transformers.

 

There is no 'best transformer' just like there is no best vehicle. It all depends what you're trying to achieve in engineering terms. Toroids are best for efficiency (low losses) and radiated flux and have wide bandwidth (low leakage flux). But in audio we don't want high bandwidth power transformers, even though we want output transformers to be wide bandwidth enough for audio.

[esldude]

48 minutes ago, DancingSea said:

How about we drop this pointless feud and return to discussing options for good class D amps?

 

Seems simple enough ???

We just can't do it. 

 

I'm stuck with class D.  I mean bad enough already right?  Mine has toroidal power transformers I think.  Bad, bad bad.  Leaking noise everywhere.  I mean the output noise when idling is literally a couple dozen microvolts.  It sounds quiet to me.  Quieter than any amp I have ever owned.  But I am having trouble sleeping at night.  I wake up with nightmares about what might be going on and still think it sounds okay when it just can't be, right?  It just cannot be. 

[monteverdi]

14 minutes ago, esldude said:

 

Not trying to be cute with you, but any of those methods can be done exceedingly well.  They all have issues to be solved, advantages inherent in the design.  But all have to have the devil in the details beaten out of them to work well.  SMPS too. 

 

In LPS you can have capacitor filtered, choke filtered, and actively regulated just to pick a few broad categories before getting to the xfmrs in use.  You can use big xfmrs for good reason and put them outside the main box for the gear to get hum away from it.  You can do what some aircraft one did run everything at 400 hz so the xfmrs can be much smaller.  

 

The bottom line is any of those can work and work well.  If I tell you I have an SMPS it might be state of the art or it might be a wall-wart radiating garbage in all directions.  Same for the xfmrs types in LPS.  You really can't say, "R-core xfmrs are the only basis for great quiet power supplies."  Or EI core or C core or whatever. 

 

This is not a bad basic explanation of the issue here:

 

http://www.audioxpress.com/article/Power-Transformers-for-Audio-Equipment  

I actually read that article before posting. Even toroids can vary a lot in their parameters depending how they are manufactured. My point was that just having preconceived notions that one type of design or part is superior to others without knowing any details does not allow to evaluate anything critically.

[monteverdi]

28 minutes ago, esldude said:

We just can't do it. 

 

I'm stuck with class D.  I mean bad enough already right?  Mine has toroidal power transformers I think.  Bad, bad bad.  Leaking noise everywhere.  I mean the output noise when idling is literally a couple dozen microvolts.  It sounds quiet to me.  Quieter than any amp I have ever owned.  But I am having trouble sleeping at night.  I wake up with nightmares about what might be going on and still think it sounds okay when it just can't be, right?  It just cannot be. 

I have a class D with toroids (Kharma MP150) and a DIY Anaview with integrated SMPS and I like the later much more (if it has to drive the right  impedance).

[GUTB]

So, there’s a reason why virtually all high end audio uses torodial-based power supplies. The common knowledge is that they’re more efficient which is important in audio applications and that they put out less EMI. But, there is some dissenting opinions on that as well so it’s not gospel.

 

There’s a reason why almost no high end manufacturers use switching power supplies — that is that they just sound worse. Switching noise is not easily mitigated, and moreover will effect the rest of the mains circuit with noise and possibly a ground loop. Basically, switching power supplies are the devil and don’t belong in audio.

 

So, why are switching mode power supplies used in class D applications? This is just my opinion, but I think it’s mainly because cheap SMPS units are made available for DIY’ers and low-end amp manufacturers. Theta, which is a high end manufacturer went with a beefy linear power supply because they said it sounded better. Technic’s reference amp, the GaN FET driver class D SE-R1 uses a giant linear power transformer with big capacitor cans.

[Ralf11]

affect, not effect

[esldude]

Maybe LPS would be better if like switching supplies we move the base frequency out of the audible range.  So we can go low.

 

I propose 1 hz AC especially for audio.  We'll need big transformers and even bigger caps.  But the 20th harmonic of 1 hz just enters the audible range.  We can make t-shirts.  

 

1ACforME

[DancingSea]

2 hours ago, esldude said:

We just can't do it. 

 

I'm stuck with class D.  I mean bad enough already right?  Mine has toroidal power transformers I think.  Bad, bad bad.  Leaking noise everywhere.  I mean the output noise when idling is literally a couple dozen microvolts.  It sounds quiet to me.  Quieter than any amp I have ever owned.  But I am having trouble sleeping at night.  I wake up with nightmares about what might be going on and still think it sounds okay when it just can't be, right?  It just cannot be. 

 

Of course, I Love Appalachian blood feud as much as the next guy ?

[firedog]

2 hours ago, GUTB said:

So, there’s a reason why virtually all high end audio uses torodial-based power supplies

 

2 hours ago, GUTB said:

There’s a reason why almost no high end manufacturers use switching power supplies — that is that they just sound worse.

 Wrong, as usual. As has been pointed out to you previously:

There are several very high end manufacturers who use SMPS. Most others don't, because:

A really good SMPS is expensive and difficult to design. We aren't talking a wall wart PS here.

 

Most manufacturers don't have  the knowledge or experience  to produce such a PS, so they don't. Too much trouble and expense for them. If you don't have experience designing them, why go to the trouble and R&D expense of producing a suitable one when alternative technologies exist that are known to you and suitable? And cheaper for you. 

 

It has zero to do with whether an SMPS can be made to sound as good or better than other types of PS, and everything to do with the lack of knowledge and cost of production as a result. 

Even in high end production, such mundane things are often the reason for design choices. You repeatedly mistakenly assume that just because a technology is found in high priced designs, that it is by definition better. Sometimes it is used because it is "good enough" (which can be very good/excellent) for the level of the design and and available at whatever price the manufacturer finds acceptable. And because, "that's how we've always done it and that's what we know how to do well'. 

 

The companies, such as Linn, that produce their own SMPS power supplies understand the desirable aspects of SMPS, and know how to produce a high quality SMPS where the less desirable aspects are overcome. As esldude noted, that scenario exists for all types of PS: use the desirable features, design around-solve the problems brought about by the less desirable features. 

 

But keep repeating the generalization "they just sound worse" to yourself, even though it has no basis in reality and has been shown not to be true as a general statement. 

[sandyk]

1 hour ago, firedog said:

Most manufacturers don't have  the knowledge or experience  to produce such a PS, so they don't. Too much trouble and expense for them. If you don't have experience designing them, why go to the trouble and R&D expense of producing a suitable one when alternative technologies exist that are known to you and suitable? And cheaper for you. 

While I agree with the first part. I think the expense is more likely to come down to economies of scale.

 I don't believe that if enough of these types of SMPS were produced that the cost would be a problem.

 Have you any idea how much a large toroidal transformer capable of powering a high power amplifier costs (500VA or more) ?

Add to that the sheer weight of the beast, and the larger enclosure needed for the amplifier as a result.

 Good metalwork is not inexpensive either, and would need to be substantial to support such a heavy transformer.

[firedog]

28 minutes ago, sandyk said:

While I agree with the first part. I think the expense is more likely to come down to economies of scale.

 I don't believe that if enough of these types of SMPS were produced that the cost would be a problem.

 Have you any idea how much a large toroidal transformer capable of powering a high power amplifier costs (500VA or more) ?

Add to that the sheer weight of the beast, and the larger enclosure needed for the amplifier as a result.

 Good metalwork is not inexpensive either, and would need to be substantial to support such a heavy transformer.

I don't disagree. But since very few applications need a high quality SMPS, they aren't mass produced. Just the less expensive noisy ones are. 

If you are producing high end audio and there isn't an off the shelf one that meets your needs, you probably won't think that designing/producing your own from scratch makes the most sense economically, as your production run won't be large. 

Add to that all the misinformed audiophiles who might be put off your product if it uses an SMPS,  and you have good reasons not to use one. 

All that weight and metalwork is a positive selling point in the high end market - it is seen as proof of quality. 

[barrows]

11 hours ago, monteverdi said:

There is a general idea that toroids are the best transformers

No there is certainly not!  Toroids produce a smaller amount of magnetic interference than other transformer designs, BUT, they have more capacitive coupling, which allows more high frequency noise on the AC line through.

Toroids are used mostly because they allow for a large transformer to be put in a relatively small space, as their radiated magnetic field is smaller, this saves money for building products, as the chassis can be smaller.  But, if you build a product with enough internal space (and/or magnetic shielding), it is better to use a quality EI style transformer which does a better job blocking AC line noise.

As you note, R-Core are often a better option, featuring the best of both worlds, but, they are difficult to source at high quality levels.

 

But, to the point of this discussion, Mr. Putzeys is saying his company can build SMPS for power amplifiers which offer many benefits over linear power supplies.  and if you looks at the measurements of such amps, it is very hard to argue with his point of view.  (No power supply related noise in the amplifier output).  This does not mean it is impossible to build a good amplifier with a linear power supply, it just means it is also possible to build a good amplifier with a SMPS, despite audiophile mythic beliefs.

[barrows]

9 hours ago, GUTB said:

There’s a reason why almost no high end manufacturers use switching power supplies

 

This level of ignorance is getting really annoying, as some people might believe you!

 

Chord, Linn, Meitner, EMM Labs, Mola Mola, and many others effectively power their high end products with SMPS!

 

As @firedog mentions above, many manufacturers do not use SMPS because they do not have the engineering chops to build good ones, and because why would they bother when so many Audiophiles believe the myth that SMPS are inherently bad.  It takes a very good engineer to tackle the challenges of SMPS design, one who is highly trained in high speed circuits and RF engineering.  Not your typical analog circuit guy... 

[GUTB]

20 minutes ago, barrows said:

 

This level of ignorance is getting really annoying, as some people might believe you!

 

Chord, Linn, Meitner, EMM Labs, Mola Mola, and many others effectively power their high end products with SMPS!

 

As @firedog mentions above, many manufacturers do not use SMPS because they do not have the engineering chops to build good ones, and because why would they bother when so many Audiophiles believe the myth that SMPS are inherently bad.  It takes a very good engineer to tackle the challenges of SMPS design, one who is highly trained in high speed circuits and RF engineering.  Not your typical analog circuit guy... 

 

Linn is not a high-end manufacturer. Chord has spoken about the difficulty of designing a low-noise SMPS for the Dave which is a low-power device. EMM Labs amps appear to use giant linear power supplies like everyone else. There are not "many others". 

 

Bob Carver

Dan D'Agistino

Pass Labs

Shindo

Audio Note

Air Tight

Luxman

Esoteric

PS Audio

T+A

Lamm

Constellation

CH Precision

DarTZeel

Gryphon

Goldmund

 

And MANY others don't use linear power supplies. The use of SMPS in the high-end, especially for power amplifiers, is very uncommon. The reason offered is that all of these engineers are dumb.

 

[Sam Lord]

GUTB,

 

You have soiled this and other discussions with so much idle speculation and falsehood that you are causing vastly more harm than good in this space.   Regarding Bruno Putzeys, he might be the greatest audio engineer ever.  He designed the world's finest ADC of its day, a fantastically elegant asynchronous design, which AFAIK still has the lowest distortion of any commercial product even 15 years after its introduction.  He transformed the world of amplification by attacking the enormous design challenges of Class D and succeeding.  His contributions extend to all aspects of loudspeaker design and many aspects of testing.  He has shared his knowledge as much as anyone in the business, including Nelson Pass.  Lastly he is quite a generous person whom I am honored to call a friend.

 

I understand your frustration with audio electronics: it is a very unforgiving field of endeavor.  You have shown far too much prejudice in your views to be taken as seriously as your intelligence might warrant.  Turn the ship around, open your eyes, and accept the value of all the hard work done to honor music. 

 

 

 

[firedog]

3 hours ago, GUTB said:

Linn is not a high-end manufacturer.

This must be your idea of a joke....

3 hours ago, GUTB said:

The reason offered is that all of these engineers are dumb.

Did you miss a lot of elementary school as a child? Please go back to school and take some lessons in reading and understanding written English. That's nowhere been said or even implied. That formulation exists only in your mind, not in what anyone here has written or what Bruno P has written. 

[GUTB]

8 minutes ago, firedog said:

This must be your idea of a joke....

Did you miss a lot of elementary school as a child? Please go back to school and take some lessons in reading and understanding written English. That's nowhere been said or even implied. That formulation exists only in your mind, not in what anyone here has written or what Bruno P has written. 

 

Bruno Putzeys did, in fact, write that and you repeated it.

 

But, I know, truth is a popularity contest. You'll have the quotes shoved right into your face but it won't matter.

[Nordkapp]

21 hours ago, kumakuma said:

 

Shaming others based on the equipment they own or the equipment they plan to buy is neither helpful nor supporting.

Haha. Equipment shaming. Now I've heard it all. 

[Nordkapp]

23 hours ago, Ralf11 said:

Would you mind briefly outlining your education and background in science or engineering, @GUTB  ??

Not happening.