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Topic: Audibility of Audio Power Amplifier Distortions (Read 35119 times) previous topic - next topic
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Audibility of Audio Power Amplifier Distortions

In the parallel thread where we are discussing audibility of conversion of high resolution audio to CD sampling rate and bit depth, there is a constant set of posts from Ammar (AJ) on audibility issues regarding Amplifiers (see this out of many examples: http://www.hydrogenaud.io/forums/index.php...t&p=882443).

I didn't think you all discussed hardware audibility issues in this forum but I am new so perhaps I am mistaken about that.  Since the off-topic posts continue to add noise to the other thread, pun intended , I thought we should have a separate thread on them. 

If the moderators feel this topic is outside of the scope of the forum, I appreciate all the references in the other thread be deleted and members barred from continued discussion of it there.

So with that intro out of the way, and complying with Forum Terms of Service #8, I present this data from none other but our own Arny Krueger.  A bit of back story on this.  We were on AVS Forum discussing double blind tests.  I realized one day that I have never ever seen Arny post the results of any ABX double blind tests in which he had personally participated.  I asked him about it and he said there is only one record of such participation in public.  And that was a test of amplifiers published in a now defunct audio magazine some 30 years ago.

I asked Arny for a copy but he said he did not have any to share with us (!).  In an ironic turn of event, Arny helped me find a copy of that issue of magazine in an auction which I proceeded to purchase.  In that regard I like to thank Arny's kind help in locating that important bit of history.

In order to be sensitive to copyright issues, I am going to post the key parts of the article.  It covers almost everything in there as the article is only 2-3 pages long.  But should you have more questions I am happy to snip other sections and post.  But again, I think you will find these to be a pretty complete picture.

Here is the title of the article:

.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #1
Is it masochism?
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #2
Is it masochism?


You have to ask, why would anybody in their right mind try to spin the results of a very straightforward article from several decades back that is based on DBTs against me?

To pursue this logically, there would have to be some place some where I said something like: "All amplifiers sound the same" but I didn't. It is my position that a sufficiently screwed up amplifier can create audible artifacts.  The only reason why we had a publishable article (published by 2 independent ragazines on 2 different continents) is because the screwed up amplifier was a product of Audio Reseach, a highly regarded  high end audio manufacturer.

OTOH how endangered is the Objectivist's card of someone who mimics your choice of knee jerk high end ragazine reviewers with absurd technical claims like these:

http://www.madronadigital.com/Library/Mark...3Amplifier.html

"
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr

But How Does it Sound?

In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
"

Audibility of Audio Power Amplifier Distortions

Reply #3
Maybe legalization made him forget that embarrassing nonsense he wrote on the Madrona site...and now it's spin control time?
Like him, I'm not even sure what the point is? Amps can sound different???

Is this another Eureka moment, like "OMG, it is possible to muck up 16/44!!!"

cheers,

AJ
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #4
Perhaps the first three posters prefer another mudfest, but if not, I suggest that those interested in clarity and efficiency immediately observe the rather sloppy paper conclusion that Amir is (again) pouncing on, and immediately concede that at least one of the amps involved in the referenced test was likely driven beyond its operating limits and thus the likely source of any audible difference. I believe that this has already been acknowledged in one of the mudfests in avsforms, so I don't see the benefit to any (other than those devoted to things other than intellectual honesty and scientific rigor) to replay that here in HA.

Audibility of Audio Power Amplifier Distortions

Reply #5
Perhaps the first three posters prefer another mudfest, but if not, I suggest that those interested in clarity and efficiency immediately observe the rather sloppy paper conclusion that Amir is (again) pouncing on, and immediately concede that at least one of the amps involved in the referenced test was likely driven beyond its operating limits and thus the likely source of any audible difference.

Not here to discuss "likely."  If you have some data to share, by all means do.  Throwing FUD on the test results with speculation is not what I consider "science."

As I clearly post, each amplifier was exhibiting 1% distortion:



So they were both equally stressed.  The listening level was just 90 db SPL.  If you think this is out of norm for a 200 watt amplifier, then you need to make your case to Arny.

Quote
I believe that this has already been acknowledged in one of the mudfests in avsforms, so I don't see the benefit to any (other than those devoted to things other than intellectual honesty and scientific rigor) to replay that here in HA.

Can we not have one, just one thread of discussion here where someone doesn't post an emotional rant like this?  If you have no interest in the technical topic, then don't engage in it.  If you think i am violating forum TOS, report me.  If you have references you want to provide from AVS Forum or elsewhere, do so.  Otherwise, please save your frustrations, angst, anger, or whatever against any DBT that shows positive outcome.  You are contributing to the mudfest in a big way with posts like this, antagonizing members.


Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #6
So one of the core reasons people go wrong here is the assumption that "clipping" is something that happens when the amp is pushed way beyond its power.  Folks imagine these waveforms with flat tops.  Reality is very different.

Here is scope snapshot I made of an AVR being pushed with a sine wave:



These circuits can get activated on narrowest peaks in the source content.  When they do, the effect is not long lasting and pronounced like above.  But rather, momentary creation of non-linear distortions that can color the sound.  You would not perceive the harshness you would expect with hard clipping.

Here is another measurement of an AVR that has one channel right before clipping and the other into it:



Notice the odd distortion exhibiting what I mention above.


Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #7
OTOH how endangered is the Objectivist's card of someone who mimics your choice of knee jerk high end ragazine reviewers with absurd technical claims like these:

http://www.madronadigital.com/Library/Mark...3Amplifier.html

"
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr

But How Does it Sound?

In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
"

If you are going to quote something, you should either quote all of it or indicate you took out something.  You did not do either.  Here is how the start of that section goes:

But How Does it Sound
OK, lots of technical talk but does any of this impact the sound? You may know that there are two schools of thought here. One that says all amplifiers more or less sound the same. The other says the exact opposite with each sounding different like the smell of two different flowers. I won’t take a position in that food fight . But instead, speak of a much less controversial issue of pure power delivery.

This is an informal write up unlike some of my other articles that are published (see http://www.madronadigital.com/Library/Library.html).  I wanted to explain the design of this amplifier and did so.  But thought I should share some personal experience.  it is subjective and stated as such. 

Importantly, I did not state any of this in this forum.  AJ went to the web site and post it here.  So not sure why you are demanding that I address it.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #8
amir, you're doing yourself no favours at all by doing this. As a bystander who reads this forum you come across as an arrogant bleep. All you seem to want to do is argue with Arny over stuff you either don't understand or disagree with. You've now started two threads purely to argue. Putting smilies all over your posts doesn't somehow make them right or funny, just pathetic.

You obviously have no intention of learning from anyone or taking any point of view except your own so why are you here? You're not engaging in discussion and this is a discussion forum.

Audibility of Audio Power Amplifier Distortions

Reply #9
Arny, with a great deal of genuine respect, you were obtuse at best in only referring to a "screwed up amplifier (that) was a product of Audio Research" that was apparently never directly and clearly discussed in the paper conclusion mentioned in this thread.  But I recall you did acknowledge that clearly in at least a few posts among hundreds of posts elsewhere in at least avsforums.

I gave you another opening, but I'm not going to do your homework for you - please reference or repeat at least the salient posts or information of your previously disclosed info on how you came to believe the AR amp was broken despite the paper conclusion that Amir is going to town on, so that Amir has as little ammo as possible on the general topic of amps and how they sound.  You can help shift the discussion at least in this thread if you'd just be clear and concise on exactly what you experienced and learned on the referenced amp test that is not immediately and explicitly obvious from the quoted conclusion that Amir is leveraging.

I have little doubt that Amir is betting that you don't have the energy or humbleness to acknowledge what you already have in other fora on the paper in question - but I hope that you prove him wrong on that.

Wanna give Amir what he wants? Be defensive or obtuse about this. No test or paper is perfect, so acknowledging that is no weakness. Wanna end this thread ASAP to the benefit of all that have a constructive agenda? Please diffuse this with a clear, concise summary of exactly what the AR amp defects were that were not explicitly disclosed in the paper conclusions that Amir is leveraging to troll for the vulnerable.

Audibility of Audio Power Amplifier Distortions

Reply #10
amir, you're doing yourself no favours at all by doing this. As a bystander who reads this forum you come across as an arrogant bleep. All you seem to want to do is argue with Arny over stuff you either don't understand or disagree with. You've now started two threads purely to argue. Putting smilies all over your posts doesn't somehow make them right or funny, just pathetic.

You obviously have no intention of learning from anyone or taking any point of view except your own so why are you here? You're not engaging in discussion and this is a discussion forum.

Thank you for the feedback.  Here is my problem with it and reaction that hopefully you take to heart.  If you really mean such things, you should send them privately to me in PM.  That you post it here, means it is done for effect as to put me down, under the cover of giving me advice. 

I had no intention of creating such a thread whatsoever.  AJ has post at least a dozen times if not more in the filter thread asking me about amplifier article on Madrona Web site.  Where were good samaritans advising him not to do that as to not reflect poorly on the forum?

Two days ago I reported one of his amplifier posts to the admins.  I explained that it is off-topic yet he keeps posting it.  No action was taken and he has gone literally crazy posting this stuff over and over again.

Here is one of his posts from yesterday:

I am not a subjectivist

Quote
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr

But How Does it Sound?

In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.

If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology.  Hearing this amplifier was an eye-opener for me.  I think it will be for you too.


 

Would love to see you start a thread about "Audibility of Typical Filters in a Class D amp" Amir. You've mentioned TOS #8 a few times, so we know you are aware of it.

cheers,

AJ[/color]


My first post in this forum was a reply to AJ's amplifier post.  I had my hand slapped and slapped hard by the admin (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106442&view=findpost&p=880379).  That is within their powers.  It is their forum and I am here to follow their rules as strictly as they ask me to do.

So when I see repeated violations of the forum rules above, with demand that I go and create such a thread as otherwise he is going to keep posting nonsense there, I did it.  And yes, I did it in a way that puts him in his place.  And did so while being 100% compliant with forum TOS. I shared new information, I brought test data that most of you have never seen.  Instead of showing interest in that, you rather give me advice in public?  And I am supposed to take it as friendly advice?  I may be dumb but not stupid .

Let's have whoever else wants to vent, give me advice, discuss world peace, my company's web site, etc. post now and get it out of their system.  When you are done, let me know and I can see how I can contribute technically.

Good grief....
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #11
Is it masochism?


Did someone say amps never can sound different?

And does Amir think this is the only article ever published on the subject?

"The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier into a Tone Control?" E. Brad Meyer, Stereo Review, June 1991, page 54


Audibility of Audio Power Amplifier Distortions

Reply #12
Arny, with a great deal of genuine respect, you were obtuse at best in only referring to a "screwed up amplifier (that) was a product of Audio Research" that was apparently never directly and clearly discussed in the paper conclusion mentioned in this thread.  But I recall you did acknowledge that clearly in at least a few posts among hundreds of posts elsewhere in at least avsforums.


One of the odd aspects of this matter is that Amir has a copy of the article that Carlstrom, Greenhill, and I wrote, but I don't. Amir can therefore easily quote the paper to discredit me if I make the slightest mistake or even don't make a mistake but create a gap that Amir can fill with misinterpretations, speculations, and outright distortions of the meaning of various parts of the article.

Proceeding bravely, the story starts in  Larry Greenhill's living room in Westchester County, NY many decades ago. It is the Saturday afternoon after I gave a presentation about and demo of ABX to The Audiophile Society at Dr. Hy Kachalsky's house the previous evening. The host's system was notably centerpieced by a Hill  Plasmatronics loudspeaker sytem.

Dr. Greenhill introduced the topic of problems reported with the combination of a SS Audio Research D120

and a Acoustat full range electrostatic speaker system
(if memory serves)

We hooked the equipment up and started to listen to it. Greenhill provided us with a certain Eagles LP and instructed us to cue up a certain track and try to crank it up a little. We were rewarded with a fairly horrific crackle on certain bass notes. One of us said something like "That sounds ABX-able" and the test was on.

Greenhill provided a far less expensive and prestigious CM Labs power amp with similar power ratings to compare it to. After carefully matching levels with a voltmeter measuring test tones across the speaker terminals, the ABXing commenced. There was no problem with obtaining statistically significant results.

Audibility of Audio Power Amplifier Distortions

Reply #13
AJ has post at least a dozen times if not more in the filter thread asking me about amplifier article on Madrona Web site.

By Jove, you've got it (even though you don't)!
Amir, once again, you can't be cognizant of or comprehend any of this, but I'll state it for the record for anyway for others.
The BS paper thread, in the LISTENING TESTS FORUM was about: Audibility of Typical Digital Filters in a Hi-Fi Playback System.
Your specious claim is that you can hear deleterious effects of the HF filtering related to 24bit>16/44 downsampling (CD) when "listening".
You then claimed on your website, to be able to hear deleterious effects of the output HF filtering related to Class D amps when "listening"
This is probably impossible for your brain, but are you following so far? Do you see the tie-in..and perhaps why the mods didn't think it was way OT and like one of your many dives into the rabbit hole?
In both instances, you are claiming to "hear" HF output filtering artifacts....except, when the amp costs $50k (2012 pricing)...and oh yes, you happen to sell it.
So...now that we are talking amps/distortion, could you please shed some details on exactly how you "heard" this HF distortion, when not being able to generate ABX logs on your Windows computer?
It seems you used Revel Salons. What sort of listener training was required? Did you adhere to BS-1116? Can we see details of the test setup (like in the M&M and BS paper), the results and how the statistical analysis was done, etc?
Exactly how did you hear the "harshness" in Class D amps vs your $50k MLs free of HF artifacts like a 24bit master?

We'll get to the preposterous claims you made about linear vs SMPS later.

cheers,

AJ
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #14
We hooked the equipment up and started to listen to it. Greenhill provided us with a certain Eagles LP and instructed us to cue up a certain track and try to crank it up a little. We were rewarded with a fairly horrific crackle on certain bass notes. One of us said something like "That sounds ABX-able" and the test was on.

Hi Arny.  Thank you for filling the details for us.  I am curious why any ABX testing was needed if an amplifier is having "fairly horrific crackle?"  Is that the kind of artifact that is subject to placebo?

As I quoted from the article, it says that you use an oscilloscope to measure clipping and it was around 1% on *both* amplifiers.  Does 1% clipping create horrific cracking sound? 

Quote
Greenhill provided a far less expensive and prestigious CM Labs power amp with similar power ratings to compare it to. After carefully matching levels with a voltmeter measuring test tones across the speaker terminals, the ABXing commenced. There was no problem with obtaining statistically significant results.

One would think so with any horrific distortion .  I don't see a step where an oscilloscope was used.  Given the statistical nature of the distortion percentage, I assume that was with real music and some kind of internal instrumentation of each amplifier which would be quite a bit more involved than what you are describing.

But yes, you are right that your subjective observations don't match the article .

Thanks again.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #15
Is it masochism?


Did someone say amps never can sound different?

There is a wide gulf between that, and actually posting positive double blind ABX tests of two powerful solid state amplifiers.  If someone showed up and said those two amps sounded different to them you guys would take away all of his credentials, take his cloths off, and leave him naked in the desert.  So let's dispense with that tactic of "who said they don't."  You all do.  Or else folks wouldn't have resentment to this thread.  And Arny's work including Arny himself.

Quote
And does Amir think this is the only article ever published on the subject?

"The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier into a Tone Control?" E. Brad Meyer, Stereo Review, June 1991, page 54

More the better.  Please post whatever you think is relevant to this thread.  Hopefully it is not some tube amp compared to solid state and such.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #16
Amir, please don't play with matches. The amount of straw you're building up is dangerous.

So this thread will have nothing to do with audibility of amplifier distortion. Something, like in the other thread, you have made very specific claims to be able to hear-"listen" for (Class D filtering and PS).
Just like the other thread, zero ability to demonstrate your spurious claims.
Let's see if we can spin for 28 pages.

cheers,

AJ
Loudspeaker manufacturer

Audibility of Audio Power Amplifier Distortions

Reply #17
We'll get to the preposterous claims you made about linear vs SMPS later.

Let's have it.

Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of Audio Power Amplifier Distortions

Reply #18
If you really mean such things, you should send them privately to me in PM.  That you post it here, means it is done for effect as to put me down, under the cover of giving me advice.


I'm not giving advice, I think you're an arrogant bleep who's only purpose on this forum from what I've read is to disagree with people and not to pay any attention to anything anyone says. Not sure I can put it more plainly than that.

Audibility of Audio Power Amplifier Distortions

Reply #19
I am curious why any ABX testing was needed if an amplifier is having "fairly horrific crackle?"  Is that the kind of artifact that is subject to placebo?


Of course, and only a still-naive subjectivist could suggest otherwise given years of posting on consumer oriented audio forums. The pros can be no different.

People get obsessed with small audible differences whether they are real or illusions. They get blown way out of proportion. "The difference due to cable dielectric is so great that my wife hears it in the kitchen."  In that regard I am no better than any other audiophile or pro - I can become obsessed with small, even imaginary audible differences and blow them way out of proportion in my mind.

I invented the ABX Comparator as a mental prosthesis to help me behave sanely and rationally.

Was the crackle really horrific? I'll bet a lot of people would have never noticed it.

The main difference between objectivists and subjectivists in audio is that objectivists can actually entertain the possibility that things may not be exactly as they perceive them. They can have insights into their thoughts and actions. They have a choice other than to take everything at face value. That means that they can actually behave like a sane adult with respect to audio.

Audibility of Audio Power Amplifier Distortions

Reply #20
We'll get to the preposterous claims you made about linear vs SMPS later.

Let's have it.


http://www.madronadigital.com/Library/Mark...3Amplifier.html

Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimeh

"While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. "

Because of  my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS. 

In addition I have some background with after market car audio, whose power amplifiers have long made heavy use of SMPS.

The following statement is denied by facts accessible to everybody who has enough electrical engineering talent to read the required plain English  labeling of the SMPS wall warts that are endemic today:  "... power supply voltage variations and noise which unfortunately get worse with switching supplies. "

Just read the label! For example the SMPS for this (and virtually every other) laptop is rated for input voltages from 100 to 240 volts (or an even wider range).  This one has a rated output voltage of 20 volts and were one to be technical enough to measure it, one would find that it has good regulation with respect to input voltages and changes in load. It also has  low output and radiatednoise - legally mandated by FCC Part 15.

Modern SMPS power supplies are vast improvements over their linear predecessors. A typical linear iron transformer-and-diode wall wart rated at say 9 volts had such poor regulation that it would put out more like 12 volts with no load and might barely make 9 volts with rated load, or not. This presumes a predictable and stable power line which may not be the case. It also produced massive amounts of noise in its output because unlike the SMPS this was not a federally-mandated parameter (FCC Part 15).  The simple brute force single capacitor filter if present allows volts of ripple noise when the current drain goes up.

Virtually every switchmode power amplifier on the market today has a SMPS power supply. They sacrifice no sound quality because of it.

I speculate that the Levinson 53 has a linear power supply because some marketing person decided that they needed to pander to audiophile hysterical fear of modern technology, particularly SMPS.

Please notice that this official document from Levinson seems to fail to make the above false claims:

http://www.marklevinson.com/tl_files/catal...010_5.17.10.pdf

The false claims in the Madronna article are likely the invention of its author.


Audibility of Audio Power Amplifier Distortions

Reply #22
If you really mean such things, you should send them privately to me in PM.  That you post it here, means it is done for effect as to put me down, under the cover of giving me advice.


I'm not giving advice, I think you're an arrogant bleep who's only purpose on this forum from what I've read is to disagree with people and not to pay any attention to anything anyone says. Not sure I can put it more plainly than that.

Ah, in that case I take back my "thank you" in my response to you . 

As to your specific commentary, I present to you this short video from one of my all time favorite movies, My Cousin Vinny:

https://www.youtube.com/watch?v=v4KR1zVqizo

This is a technical topic.  If you have some rants about me, please create a separate topic and post it there.  You are antagonizing the membership with off-topic personal insults like that.

Amir
Retired Technology Insider
Founder, AudioScienceReview.com


Audibility of Audio Power Amplifier Distortions

Reply #24
Because of  my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS.

???  Please forgive me Arny for being blunt but that is like the gas station attendant saying he is intimately familiar with the engine in your car because he has put gas in thousands of cars .  All you need there is a screwdriver to bolt a power supply to a PC case.  And plugging in its cable into the motherboard.  That gives you no understanding of how PC switchmode power supplies work.  My kids in elementary school were building their PCs and I am pretty sure they, nor their friends had any idea how they worked.

The discussion here is about class D amplifiers.  Contrary to popular myth, class D does not mean "Digital."  The letter D was just the next one in the alphabet.  So you working with mainframe computers gives you no familiarity whatsoever with the design of class D amplifiers.

As you may recall, you and I had a conversation about amplifiers design on AVS Forum.  There you proceeded to explain the schematic of Bryston power amplifier only to confuse the control microprocessor schematic with the power supply!  https://www.google.com/url?sa=t&rct=j&a...Fji7W--NGJ4qhIg

You were kind enough to admit that: http://www.avsforum.com/forum/91-audio-the...ml#post23981673

Quote from: Arny on AVS link=msg=0 date=
Yes, I misread the schematic which is really disappointing.


Let's have AJ sleep in the bed he has made and explain what he meant with that bold statement.

Happy thanksgiving Arny.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

 
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