Class D

Oh dear, https://youtu.be/YTY26k0CA0I?t=5

So you calling Rubbish! instead of calmly trying to explain yourself, is not hostile.
Stop your shilling and go back to slowly dying tubes!

Just one word for you and the amount of global feedback you have to use to artificially correct the phase shift down into the audio band introduced by the output switching noise filter, i.e. RUBBISH!!!

Stop trying to divert that you were very anti GaN, and now pro just because it will be "the format" and suit your sales/profit modeling.
One thing you "may" not have factored, is going to be the ones at less than 1/2 the cost of yours, and better advanced from those bigger companies.Now GaN is even making a "big noise" into car poweramps now also.

It you that continues to shill and have no idea!

https://www.stereophile.com/images/1220PS1200fig03.jpg



Really! Wake up and smell the roses!!! and stop your shilling!

For one it was done at very low power, would be much worse at normal power
Yet even at very low power anyone can see it’s distortion rising markedly from 1khz! up, and then much sharper after 2 to 3khz!!! to a cliff face at 5khz and up!! https://ibb.co/6rfG2ts

Here is the distortion from a good linear amp. https://ibb.co/8rTdp3D

Oh dear!

Once the switching noise is removed when very low power testing using the

"Audio Precision’s auxiliary AUX-0025 passive low-pass filter, which eliminates noise above 200kHz that might otherwise overload the SYS2722’s input circuitry."

You can get either a clean square 10khz square wave, but it's almost indistinguishable if you don't use the AUX-0025, because of the imbedded switching noise, because the amps output noise filter is set very high > 100khz

Or you get a very slewed sick looking 10k square wave with phase shift, but with not much imbedded noise because the units output filter is really working hard down low <100khz.

What ever you do, neither is right.
The only right is as Technics did move the switching frequency up 3 x higher to 1.5mhz and then so also the switching noise filter, then it can do it’s job properly and not effect the audio band with phase shift from 20khz down.

You you don’t even understand what you asked, they utilized one graph instead of two just to confuse the likes of you

Common jonesy really!!

The "ohm" is for the blue trace showing output impedance of the amp v frequency

The red is just phase degrees v frequency
On very good "phase correct" speaker/drivers that you paid big for!! and especially ESL, you would hear upper mids and highs that are 70 degrees (almost 25%)  out of phase, compared to being in phase from below the upper-mids.
Why do you think good manufacturers strive for "time coherent speaker design", even going to the lengths of staggering the drivers mounting distance to the listeners ears.

Of course class D is good

+1 for "good"

NO they are not a Pass Labs amp

+1 on that too, and other amps I’ve mentioned as well

I love them doing bass duty..Nice and cool running

+1 here too, so long as the load isn’t too severe as they will current sag.

Nice and cool running for the summer months doing mids and highs

+1 again, but can’t yet compete with a good A or A/B amp yet, which run far hotter

Time to feed the chickens..

+1 except mines wombats/koalas

Cheers George

George,

Could you please explain

No! sorry but your the fool sunshine!! 
Just 3 posts and you've decided to become the technical referee?? 

Tag team shilling that’s a new one for Audiogon.


And Ralph search is your friend, you might want to be reminded, that you were anti GaN fets way back at first, they are still the same ones buddy.

Your so full of it, all you have on your mind is to get your Class-D out there in the best possible (even if false) light that you can, anyone can see it.
You would have been better just bringing it out quietly and hopefully resting on the laurels of your history on tube OTL’s.

One more time for the masses, Class-D is not yet in the "very hi-end range" of amplifiers, like the Classics linear A A/B beasts that are still being made now, or even from yesteryear. Technics Class-D with the SE-R1 are the closest still to date.

Georgehifi idolizes Technics

This answer is for others that are interested.
Yes I sure do admire them in Class-D circles for advancing/sorting out (in the SE-R1) one of Class-D’s main problems, switching noise filtering which creates up to 70-degrees phase shift down into the audio frequencies https://ibb.co/MS3xC6M. Without like some do resorting to a band-aid fix of throwing heaps of "musicality destroying global negative feedback at the problem", pity they don’t want to, or maybe just don’t have the design skill to be able to what Technics did, and put it in the too hard bin??.
The other problem is current delivery into very low impedance speakers, like the classic linear high end amps can, that could take some more time, but they can drive the speakers that aren’t such a savage/nasty load like Wilson Alexia etc, so it’s not an overhaul big problem.

Cheers George

I have to say georgehifi according to you the only amps anyone should EVER own are Gryphon, “big” Krells, or D’Augostino, maybe a JC1 pair.

Lot more big BJT's than just those sunshine

At least your reading about some of them 😉
Must have something that tweaks your fancy 😘

Cheers George

And just because an amp uses tubes, doesn’t make it good. And just because an am is pure solid state doesn’t make it good.

To me the purest form of amplification "so far" to date with least colourations, lowest distortions, unrestricted dynamics, unrestricted current ability even into very low impedances, and for hard to drive speakers
Is high biased Class-A push pull direct coupled solid state amplifier, using complimentary bi-polar output devices with appropriate power supply/s and input/driver stage.
Guess what some of them are? Gryphon, Classic/Krells, Dan/Agostino, some Mark Levinsons etc etc etc.

Unfortunately, these are heavy, costly, and expensive to run.

Many say Class-D is there, I say no not yet, unlike the few here will like to have you believe.
And many others say also myself there are problems with it in the upper mids/highs.
Also it definitely can’t compete with the above into hard low impedance loads of many of speakers, no matter how many watts they have.

Cheers George

newest ICE amps switching at 1Mhz

If you can believe it (please put up a link), that’s a step in the right direction, hope the output switching frequency filtering went up accordingly, like the SE-R1 did, to minimize the phase shift down in the audio band, with resorting to throwing more (music destroying) global feedback at it.

Congratulations George you figured out how to make those Ncore modules sound like bad 1980’s tube amps.

Yeah right your dreaming , they have nailed the Belcanto Ref 600m’s in an A/B at our audio society meeting , using the same MSB discrete dac as the source, the extra buffer is not needed, and it sounds much better without it, if the source is up to it’s input stage 2k loading and low 13db gain and my dac is, you guys have a lot to learn.

It’s almost like your shilling here for someone here??

I don’t know George some of the best sound quality I’ve heard came from Class D amps in active speakers. Effortless from top to bottom.

Bet you just love the sterilised, harmonically stripped sound of the $15k Kii THREE active speakers


Cheers George

Over your head that's for sure.

Is that the same NC500 you bypassed the buffer clearly violating the recommendations of the app note that the amplifier stage be driven by a low impedance source to maintain performance?

You buy them without buffers get a life!!
Just yet another furphy of yours, that you can’t remember to see the forest for the trees??
Yes as I told you once before (is your memory shot) because my MSB dac has twice the output voltage needed from it’s very low output 10ohm impedance balance direct coupled outputs to drive the NC500 balanced input direct, so NO!! buffer board is needed!!

Well, yes good actives do impress, but I bet my bottom dollar those same active speakers can sound better even again, if they were Class-D on the bottom still, but a nice Class-A or A/B linear on the mids and tops or even the Technics SE-R1 then it won’t be hungry for current "if" the speakers are very demanding with low impedances.

The best I’ve heard Class-D was with BelCanto Ref 600m mono blocks, but into a very easy load 2way speaker with Raven 4ohm benign ribbon tweeter, so much did I like it I bought the same Hypex NC500 modules and use the direct with no buffers and in my second easy loaded system, as you have also.
But they don’t stand a chance in my main ESL based system up against this amp, which BTW has much less wattage!!! .
https://ibb.co/qn6Wnms
https://ibb.co/Qncvkkf

Cheers George

Correct, that why I like passive preamps also, if correctly implemented, as they have no sound.

Listen to many Class-D’s they have great bass great lower mids, but "something thins out" and looses it dimensionality in the upper mids and highs, like a separate amps has been grafted in suddenly.
This is what I mean they when I say they (Class-D) don’t sound like the A or A/B classics amps, effortless (invisible) from top to bottom without character change at all.

Cheers George

Wasn’t even addressing you, but seeing you butted in yet again, wonder if you understand your own ears, I doubt it very much, as you seem to think all that counts is wattage, and have no idea, just how bad global feedback is for sound quality when not used sparingly, and why some of the best sounding amps ever made have only local feedback.

Mola Mola Kalugas No, it is not as good overall as a great  A / AB mono amps. But it does sound great. And it is small, beautiful, cool to the touch, and fits in very well in an 'upstairs family room'.  And it is small, beautiful, cool to the touch, and fits in very well in an 'upstairs family room'. My basement system is better.

Correct, they are a compromise, as they stand. They still need "two problems" addressed I mention, one Technics have done with 1.5mhz switching frequency in the SE-R1

1: They have to correct the phase integrity through the upper-mids/highs (up to 70 degrees out of phase) https://ibb.co/vvwzGV5 because of the (switching frequency and it's output filter) WITHOUT resorting to "musicality destroying" gobs of global negative feedback to repair, as some have tried.

2: And the other is "current ability" to "resemble" doubling of wattage as frequency halves from 8 to 4 to 2 and hopefully maybe 1ohm, so they're not "current starved". Unlike the classic larger A A/B models  Krell, ML, A’gostino, Gryphon ect ect are capable of doing all day and yawn at it.
I can't see this happening with Class-D until future output stages/devices are re-design (maybe with even bi-polar dveices).
And then hope the SMP's are up to powering it all, with no current limitations also, if not then back to better big bulky no noise linear power supplies like I use with my Hypex NC400 (BelCanto Ref 600m) monoblocks.

Time will tell, if they can ever match todays "classic hi-end linear amps", that also took ages to get where they are, from the early days of horrible germanium transistors amplifiers that tried to take over from tubes.  

Cheers George    

Your the fool sunshine, for accepting Class-D the way it is, it has a long way to go to equal the likes of Krell, ML, A’gostino, Gryphon ect, as it is it will only ever be mid-fi if the two problems I mentioned above do not get improved on.
Technics has fixed one of those problems in the SE-R1 Class-D, and "maybe" also the cheaper integrated SU-R1000
And it will never be able to drive magnificent yet very hard to drive speakers like Wilson Alexia’s, like a big Krell, ML, A’gostino, Gryphon ect ect ect can.

that is drive 1-ohm Scintillas

Yes many can "handle" but have pitiful current, because some even have trouble equalling the 4ohm wattage with a 2 ohm load, let alone trying to double. Some even go backwards!!
And as for 1ohm, again they might "handle" it without it dying.

But compare it to a Classic Krell or similar and see which sounds better at 1ohm or 2ohm!

That's why you'll never see independent measurements on Class-D showing it can "almost" double the 4ohm into 2ohm and again into 1ohm from 2 ohm.

Cheers George

Dream on Eric you have no ears, it has problems, and Techincs have gone the distance in the SE-R1 in curing one of them it with 3 x higher switching speed (1.5mhz) and so 3 x higher low order output filter, as not to introduce any phase shift down into the audio band, without the need to increase any global feedback as some do, which we all know, large amount of feedback is not a good thing.
Also Class-D has problems with low impedance loads, that’s why you never see independent tests showing the 2ohm wattage almost doubling the 4ohm wattage. Even the Technics SE-R1 still has this problem. You have no idea!

that you lie or get hostile about something

Hey sunshine, if you look back just one post, it's Ralph that got hostile calling rubbish on me first, I just reciprocated the same back, get a life, or stop shilling/stalking 

Rubbish. Bruno Putzey’s UcD module, which is quite old at this point (and predates NCore and Hypex), has less than 1 degree of phase shift at 20KHz. It switches at 400KHz and is self-oscillating, with about 40dB of feedback.

Serious!!! your rubbish, those things have always sounded crap in the upper-mid/highs, most probably because of all that global feedback, that’s why it’s considered an ok bass/sub amp.

It does not matter that Levinson used a bunch of air core coils (one thing does not make a whole).......what matters is the sound.

I did not say that it was the idea of  series'd air core coil output filters that ML used to get a steeper roll off as not to give phase shift down into the audio bad that made it sound bad.
The fact that a big company like Mark Levinson knew that it is a problem with Class-D, as this phase shift graph from output filters shows (red) https://ibb.co/vvwzGV5

That's why it's seems only fixable by moving the switching frequency and  filters way up higher so there's no effect of phase integrity down into the audio band, and the only way to do this is move the switching frequency up much higher to 1.5mhz and the filter as Technics did with the SE-R1 and hopefully with the SU-R1000 also.

And you can't fix it but throwing "more global feedback" at it, as that is a sound destroyer in itself.  The only way is the > 1.5mhz switching frequency, so the filter can do it's job without introducing phase problems down into the audio band.

Ferrite messes up the sound. So, why do we have ferrite coils on the output of all class D amps? It is because they are smaller, cost less, have less resistance, run cooler and have better contained fields so there would be less rf outputting the amp. It is not because they sound good. If you use a better sounding air core coil the board has to be bigger, the coil costs more, you have to use a large gauge coil to get the resistance down, and you might have to add more shielding in the amp to make it pass rf standards.

You got that right at least!! and it’s why ML in their megabuck class-D flop, use big "air cores" in their No.53 monoblock, and used 4 of them in series to get a far steeper slope to cut the switching frequency noise out, so it doesn’t affect the audio band phase integrity.
https://www.stereophile.com/images/styles/600_wide/public/011212ML53-600.jpg

gFi it’s shocking that you don’t know the difference between your and you’re/you are you’re- you’re ignorant

You’re ignorant, I meant to say (your amp)
Either, or either, so long as you know. To me the fact is you’re being ignorant to this graph.
.

You still need to let it sink in sunshine, I showed you what your amp that you push incessantly does to the phase integrity of the upper-mids and highs, up to 70’ out of phase!!!!!
Oh yes!! wonder why most gripes about Class-D’s sound, is about the upper-mids and highs, never it’s bass.

https://ibb.co/vvwzGV5

You still need to let it sink in sunshine, I showed you what your amp that you push incessantly does to the phase integrity of the upper-mids and highs, up to 70' out of phase!!!!!
Oh yes!! wonder why most gripes about Class-D’s sound, is about the upper-mids and highs, never it’s bass.

https://ibb.co/vvwzGV5

Whatever sunshine, your the man. And thanks again for the bit of shilling.

None of the others have the product they sell as their avatar.

Thanks for that, you can't tell what it is till you zoom on it, you need commission for that little shill.

1. Class D audio (under the Premium Audio name) will soon be releasing their "baby" GaN amp.......stereo, 150 watts a channel into 8 ohms, balanced and unbalanced inputs for a mere $699. 100K input impedance. You will see a tiny bit of info here....wait for the second slider to load to see the pic

https://premiumaudioproducts.com/

Looks very much like the older USA company USA Audio or something even the advertising and MADE IN AMERICA proudly stated, if you look back at my GaN posts, they did say when I emailed them about a year or two go they’d be bringing out an US made Class-D using GaN technology soon, and it will be under $2K.
Guess they finally done it.

PM: Guess they’re Covid effected, as the sites closed to any ordering.

To others that care about these forums.

All we have are manufacturers and their shills, with incessant agenda to get he ball rolling on their latest class-D products, and they use these forums to slyly advertise what they have coming up for sale, and will stop at nothing to counter anything that may effect those future sales.
See the immediate angst cause to them with the professionally ready made diy GaN Class-D kit I put up above, which is probably better than anything they could do.

One here especially put rubbish on the new GaN transistor technology way back when I showed it to all here, and he said it has no advantage over the Class-D technology used.

But now he’s has changed his tune and is actually pro GaN transistors, funny what the mighty $$$$ brings out in people. Like I said they are just here to slyly advertise their goods. You can’t believe them, especially the fusers!

At least companies that use GaN like Orchard Audio, AGD ect don’t come here behaving like them.

Cheers George

Build your own GaN based 200w 8ohm stereo power amp

For those who have experience and can kit build, here is from the ones that made GaN technology happen for Class-D.
A ready made 200w @ 8ohms 300w @4ohms stereo Evaluation board for $1k.
Stick it in a nice ready made Chinese chassis add a powersupply and your up and running.
I don’t think they used the 1.5mhz switching like Technics did, but it should be as good if not better that anyone else’s that will be much more expensive

https://gansystems.com/wp-content/uploads/2020/05/GS-EVB-AUD-xxx1-GS_Technical-Manual_Rev-200526.pdf

https://au.mouser.com/new/gan-systems/gan-sys-gs-evb-aud-xx1-gs-audio-evb/

https://au.mouser.com/ProductDetail/GaN-Systems/GS-EVB-AUD-AMP1-GS/?qs=vHuUswq2%252Bsym8eVHEaFTmw%3D...

Cheers George

Must be soon, you really have gone into full product protection mode, and there’s no stopping you.
Good luck is all I can say, for your new Class-D venture.

And Class-D technology has not progressed as much as you want all to here to think (for sales), sure the GaN transistors that I first showed here years ago as a far better alternative for Class-D, you were quite negative about back then, and now you say you use them. How ironic.
I first showed the GaN power transistors from EPC (https://epc-co.com/epc) inventors of the Mosfet, to all here many years ago, and yes they have improved things a little, but the only one to use them fully and make a dent in Class-D’s Achilles Heel "switching frequency/switching noise/phase shift" has been Technics with the SE-R1 and hopefully the new SU-R1000 integrated has the same genes.

This statement is wildly incorrect! So this isn’t just about power!!

It’s more about power, because you can’t see the forest for the trees, with what Mark Levinson tried to do by series up "low order" output filters (so they don’t burn out) and trying to get a steeper roll off as not to introduce phase shift into the audio band in the upper mid/highs, which they achieved, but it had then other problems. https://www.stereophile.com/images/1212ML53fig02.jpg
Instead the simpler fix of of doing what Technics SE-R1 did and just raise the switching frequency to 1.5mhz.

Sorry, again, your show how ridiculous your statements are.

How is that any different from digital audio,

The amount of power the filter has to contend with in Class-D amps compared to a dac, now your showing how ridiculous your statements are.

https://www.stereophile.com/images/1212levin.side.jpg note the size of the 4 x!! output switching frequency filter coils in this $53K ML Class-D they had to use, and that’s a monoblock. They tried to series them all up from what I was told, to get a quicker/shallower roll off, as not to effect the phase down into the audioband like this https://ibb.co/vvwzGV5, but it was a disaster as I believe they reacted with each other at certain frequencies and rang, which was what they were trying to get rid of in the first place "switching frequency noise"

Fig.2 Mark Levinson No.53 Reference, small-signal 10kHz squarewave into 8 ohms (no AP testing low-pass filter).

An amplifier with a switching output stage produces ultrasonic noise. However, with no signal, the No.53 had 7mV of noise with a center frequency of 197kHz present at its speaker terminals, which is significantly lower in level than with a conventional class-D amplifier.

(The Anthem Class-D amplifier for example) https://www.stereophile.com/images/1212AM1fig02.jpg

But it worked in getting rid of the switching noise in the $53k ML class-d by here is the 10khz!!!!! square wave with NO external AP testing filter used, almost perfect https://www.stereophile.com/images/1212ML53fig02.jpg, no embedded switching noise, "unheard of for a class-D", except for Technics SE-R1 with does it by moving everything (switching frequency and low order low pass filter) up much higher to 1.5mhz.

The notion that you need Mhz sample rates to achieve high-quality reproduction is pretty ridiculous

No because it's only to get the low order output filtering on the speaker output up high also, so then you can get rid of "all switching noise" without effecting the phase integrity down into the audio band.
Like effects this. 70 degrees out of phase at 10khz and still out of phase at 1hkz https://ibb.co/vvwzGV5
And mhz switching frequency will DO IT WITHOUT the use of large amounts "global feedback". And ghz in the future even more so maybe one day.

NB: Not ridiculous!!!

All I can say Ralph after all your put many downs on anything mentioned threatening the release your upcoming Class-D. And all the technical praise you give it.

1: Better be a real good one
2: Designed by you.
3: Have no after market "tweaked" BS modules like, ricevs, pascal, Rowland, red dragon etc etc etc, it may exposed for doing it.
4: Be reasonably priced

George missed my debunking of his use of Cyril’s comments earlier on this page.

You are good with tubes granted, but sales for them, especially OTL are waning, you need to shill for you Class-D, you are nothing compared to Cyril Hamer for solid state design. And here the story ends.

The idea that you need GHz switching speed in a class D amp is rubbish.

And that’s another twisted furphy of yours. That statement of his say mhz for now as Technics have done with the SE-R1.
And the the ghz reference said by him is looking into the future of Class-D.
  
Can you or the other one see the forest for the trees, or is something like the mighty $$$ stopping you?
https://cdn.blog.ucsusa.org/wp-content/uploads/csd-blog-head-in-sand.jpg

I will state again for the slow kids at the back of the room

There's only one slow one here, that's you sunshine. 

Please show what you’ve done in solid state amp design, that can even come anywhere near close to Cyril Hammer’s Soulution range of power amps. You should at least believe him about Class-D switching frequency if not me.

I think Cyrill Hammer (of Soulution) https://soulution-audio.com/
knows more about solid state circuit design in his little toe than you and ralph combined could wish to know in your lifetimes.

needing switching in the GHz range is really quite laughable.

There you go again, he said

"that provide switching frequencies of several MHz or even GHz."

"Even" is the word there sunshine, looking towards the future would be even better to have ghz when technology allows, to get rid of every little trace of switching noise, without any phase shift anywhere near the audio band. Stop being such a putz.

I don’t see anything.
That GHz comment really makes me suspect his depth of knowledge on the topic is really quite weak.

True, "you see nothing."
Please, and to state his knowledge is weak, is seriously laughable coming from you.

If Class D was even 10% as bad as he makes it out to be it would be a non-issue.

Laugh all you like, Putz!
Like I said you are the rumour spreader, not once have I said Class-D is bad, if fact I’ve praised the Hypex NC500 with linear power supply monoblocks (given the right loading) that I own in my second system. Class-D has yet to reach the same sound quality as good linear amp in the upper mids and highs.

What you need to get right, is that I say Class-D the way it’s used (except for the Techincs SE-R1) has problems that MANY hear in the upper mids/highs, the deaf may not hear it.
And this is a long way being fixed in the Technics SE-R1 by having a 1.5mhz switching frequency/low order output filter instead of 400-600khz as all are today.

And those that are, or going to use the GaN transistor technology have the chance "to use 1.5mhz", but don’t, probably because they don’t have the R&D knowledge skill of Technics behind them to do it.

And btw Cyril Hammer was the first to say this, even before GaN transistors were released to the market. And has more solid state knowledge in his little toe than some "tuber" here saying anything else.

Cyrill Hammer (Soulution)

"if you want to have your Class-D product performing at the cutting edge it is not possible with todays known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz."
https://soulution-audio.com/series7/soulution-701-mono-amplifier/