" Where are we at with class D right now? Everyone keeps saying that the future is class D but where is that in the future?"
I do too, and it will come, when they've got it all right, with no compromises. When they get rid of it's "flaws". Every detractor of Class-D never complains about it's bass or upper bass or even lower mids, it's always about the upper mids and highs. Technics with their $20k SE-R1 have broken the Class-D norm and got most of the way to fixing these "flaws", by using a switching frequency at twice the norm, instead of around 600khz they've gone with very special GAN components to double the switching frequency to 1.5mhz, (3mhz would be better) this then allows the low order switching noise output filter to do it's job completely without leaving any effects and any left over switching noise artifacts within the audio band. Cheers George |
I have looked over that Technics technology and hope that it may trickle down into more affordable components as right now 20k is a very hard sell to non believers.
It like everything in technology life it will come to the masses. Just look at all the Formula 1 improvements that all come to your family car within a very short time. Hopefully somebody can make it happen for a lot less dollar! It will, those same EPC guys who made the GAN transistors for that Technics SE-R1, were also the inventors of the "power mosfet" many years ago. They are the inventors (Formula 1 guys) and they sell their inventions to the big semiconductor manufacturers, who then stamp them out by the thousands, and supply them to the masses. Cheers George |
My amps are using the latest Icepower modules (IceEdge) and switch at 500K......however, with the right massaging, they produce sound that is beyond my own designed class A amps
I see just someone shilling his wares. Massaging 500khz switching frequency will only get you half the way to a happy ending. Try 1.5mhz like Technics did, and you'll finish on a bigger high. Or 3mhz and you be in orbit. It will come soon enough, as I said EPC the makers of Technics SE-R1 GAN transistors are the Formula 1 pioneers of the Class-D world, just like they did with Mosfet transistors many years back, and look how quick they took off, must have made EPC some crazy big royalties, they are inventors that sell their patented inventions to the highest bidder. The forula 1 guys of Class-D. http://epc-co.com/epc/AboutEPC/Team.aspxhttp://epc-co.com/epc/Applications/ClassDAudio.aspxCheers George |
the noise problem is dealt with through good layout and compact (surface mount) design. Really then no one one yet has been able to rid of this, and they are mightier minds than you. Only Technics has so far been able to reduce it greatly, with double the switching frequency speed and then the normal output low order filtering of it. As you can see in this simulated 1khz square wave shot, the ideal is the "grey" square wave no ringing. The "red" is the what’s available today and it hasn’t changed, the last photo below is whats representative of today’s class-D’s The Technics is the "blue" uses the GaN transistors, very fast quickly settling and reduced ringing, much closer to resembling the ideal grey square wave.
https://ibb.co/87Kh2mVAnd now bench tests of Stereophile, use a special very low power high order -100db line filter between amps output and test gear input. (Audio Precision’s auxiliary AUX-0025 passive low-pass filter), Which eliminates noise between amp’s output and test gear input so reader can’t see it anymore. 1khz square wave with AUX-0025 filter in place: https://www.stereophile.com/images/1212AM1fig03.jpg1khz square wave without AUX-0025 filter in place: https://www.stereophile.com/images/1212AM1fig02.jpgCheers George |
600khz v 1.5mhz switching frequency
The higher the switching frequency the higher the low order output filter can be set, so by the time the residual reaches 20khz what’s left with the 1.5mhz is down nearly 3 lower in amplitude and has less phase shift in the audio band than that of normal 600khz switching frequency. Blind Freddy can see that. |
I repeat, Blind Freddy can see that.
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I will be A/Bing my super tweaked dual mono IceEdge based amps with the BHK. We shall see what we get.
You and Ralph both, then we can have a clam bake. And you two can have it out. |
ME
Typical of kalali to slur, when can't understand, he can’t see the forest through the trees. |
How am I playing both sides of what fence? The selling propaganda fence of http://tweakaudio.com/ $60 plus audiophile mains fuse. If there a buck to be made from the gullible with snake oil products, mains fuses would have to be at the top of the list. I will not longer respond to you, George . I’m devastated |
What evidence? You know, like 80,000 fancy fuses sold. Hel-loo! Wake up and smell the coffee, guys! ☕️ Mention mains fuses as "snake oil" and look who shows up, the king of directional mains fuse detection, really, and the rest of the fuse crew follows? |
Nelson Pass once said
"The first watt is the most important watt"
Cheers George |
jeffwyo577 posts12-22-2018 2:53amClass D, as soon as your warranty runs out have fun getting somebody to fix it if & when it goes down, with all the surface mount components in new digital amps most techs won't touch them including me
This is also so true, yes built in obsolescence is what they do have, when they go smoking it up. The switch mode power supply (smp) board can "sometimes" be fixed but they do fry up in a spectacular way. The Class-D amp board, when it goes up sometimes becomes a junker, you can usually say goodby to them. And the manufacturers charge like a wounded bull for a new board, even at trade price, that's if they still have them as a spare part. It's sometimes better just to get a new amp if both smp and amp have blown. Cheers George |
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Nobody will be calling any class D amp "legendary" 10 years after it was sold. They’ll all be in landfills. Correct, not only do they sound questionable to many, but owners will be cursing the day they purchased them. As replacement boards will not only be obsolete, but very expensive if NOS in stock. As no one will be able to fix them down to component level economically, 4 layer pcb, double sided componentry, and all smd! all squashed into the size of a pack of cards, good luck !!! Cheers George |
newest class D amps are so good and so cheap that you could just throw them away
That's just great, depends just how well off you are. Try saying this to an owner who Class-D has just smoked it, as see what you get back in return. Also you sell them, so you and are definitely not impartial. |
tweak1
No one has mentioned GaN class D yet. Seems to be a game changer
You need to get out more. https://forum.audiogon.com/posts/1664763
teo_audio
If GaN acts like a V-Fet or a SIT, then they might be on to something.
And they are, the EPC guys (
Alex Lidow ceo ect) who invented the GAN, also invented the power mosfet many moons ago and sold the rights it to the world, for the moment only Technics are using the GAN with their limited availability $20k SER-R1 amps. Chers George |
There’s a huge difference between a pre-amp and a power amp. Correct, two different active Class-D subs and one SR reciever I’ve had on my HT system, have eventually blown their smp caps, and in a chain reaction taken out the class-d amp as well, luckily new plate amps were available, and at trade price, just cost effective to repair for myself only, no way for a customer, they would maybe have been better of as Ricev’s said junking it and buying a new one. Cheers George |
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Haven’t found a digital which can compete.Most digital are to clean for my ear. Sterile with no decaying harmonic structure, creating too much dead time, are the words I believe you should be using. Cheers George |
There’s always a next-great thing. In the case of fast transistors, cool. Show me an audible benefit that everyone can hear before I get that hyped up about it. It’s what the present Class-D "cons" are all about, listen to a SE-R1. I’d lay money on it, that you’ll put one of the first with your hand up for one when it suits your pocket. And your old one with the lower switching frequency, will become unsellable junk save for use as a bass amp. Cheers George |
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For more information, you may want to contact the company.
Regards, G. If they are using these EPC GaN transistors in this prototype, the only reason would be to be able to attain a far higher switching frequency speeds to 1.5mhz like Technics with the SE-R1. Can you point to a link where you saw this is stated?? Cheers George |
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erik_squires
Which measurements, @kosst_amogan for which specific Class D amplifier?
make up your mind your making everyone dizzy. One day you put s**t on anyone that presents measured proof, the next day your quoting or asking for measurements, ya can't have it both ways sunshine. |
The switching frequency is at 450kHz, no tweeter could possibly reproduce that... Not that anyone would hear it, not even dogs. You need to understand better, it’s not the switching frequency "so much" but the "output filtering" needed to get rid of it that ’s problem, which gives phase shift problems right down to 3-5khz (the mids and highs of the audio band). (That's why any complaints of Class-D is the upper mids and highs, never bass or lower mids). If that switching frequency were to be moved up 3 x higher (like the $20k Technics SE-R1 does with the GaN transistors) then that "output filter" can be also moved up by the same amount, then the phase problems move up as well in the audio accordingly. I would like to see 5 x higher. Cheers George |
which has to be filtered in order to prevent the analyzer from having difficulty; in JA’s words: This is just pure BS and you have been sucked in by those words "your just echoing Stereophiles words" that are advertiser driven, and anyone can see it. And I think you know that, as you don’t want your Class-D to look bad when a 1k square wave is put through it. As no such AP filter was used at Stereophile before, when all Class-D were measured with the same analyzers. And it showed just how bad what was coming out of Class-D’s. Also when the AP filter was introduced, Stereophile use to give the wave form shots with and without the filter. And then later mysteriously only with the filter, probably because of manufacturers complaints how bad it looked without filter. So one can see it was just the ugliness of the wave form without the filter, that potential customers didn’t like seeing, and this effects sales, and advertising. Just like ricevs (Tweak Audio) you are both protecting your soon to be released Class-D amps, and just ricevs you do/say anything not to tarnish it’s launch. Again a blind man can see it. |
Doesn’t matter what spin you put on it, your just in future product protection mode like ricevs. I suggest all members here to look close at these two scope shots of the same Class-D amp this one without the "AP filter" used, this large % of switching noise is what’s being sent to the speaker, and it is NOT repeat NOT!!! going into slewing protection. https://www.stereophile.com/images/1212AM1fig02.jpgThe this a shot of the same amp exactly the same scope shot, but this one with the "AP test filter" in place, exactly the same save for the deletion of the % of switching noise, that gives the impression that this is what goes to the speaker to make it look good to the buying public, but it’s not, whats above is! https://www.stereophile.com/images/1212AM1fig03.jpgAnd let me say, what ever you look at, these are both pathetic looking square wave shots, even for an old cheap 1970’s solid state amp to be producing, yet alone a "today’s state of the art modern Class-D" the only one approaching that is below and now the new GaN transistor equipped Merrill Audio Element 118 monoblocks. Now look what happens to the GaN transistor equipped Technics SE-R1 with far higher switching speeds. The blue trace is what the Technics can produce (hardly any residual switching noise, and look how straight up an down the sides of the square wave is this indicates hardly any phase shift down into the audio band, unlike the 2 above who’s sides are quite inward tilted which indicates phase shift into the audio band. https://www.technics.com/content/products/r1/images/se-r1-img2-2-uk.pngCheers George |
If you like Class-D as it is that's fine.
Others say they can't, and it's always the mids and highs that is the problem, never the bass because that's what they're good at ever since they first came out.
And the title of this thread is. "The Future of Audio Amplification" and it will be Class-D one day, when they have a total acceptance in the mids and highs for the hiend, not just with those that can't hear it for some reason.
And that one day is getting closer with amp like the Technics SE-R1 and also maybe the
Merrill Audio Element 118 monoblocks if they did it right like the Technics. |
Ricevs, your only protecting your new Class-D baby your soon to unleash on the public, built around the Icepower Class-D modules, it’s as clear as the nose on your face. here’s a free plug, but I think it’ll end up a furphy. http://tweakaudio.com/EVS-2/EVS_1200_amplifier.html |
The resistance to innovation on this forum is frightening. There’s a reason for it, it’s there and real, and if you can’t hear it, fine. But please, don’t tell others they can’t, when they can, and the measurements back them up. And you can’t refute the amount of listeners that can hear the problem with the upper mids and highs. Even the very best of manufacturers have said so, no need to paste up that list again. Some here that have a monetary gain in Class-D and others that own them, refuse to believe that other can hear a problem. They can keep their https://wonderopolis.org/wp-content/uploads//2015/03/1425_3.jpg |
Listeners having a problem with their mids and highs have a system problem not a Class D amp problem.
They don't have the problem without the Class-D in the system, are you listening to your self, and you call yourself a room tuner.
I wouldn't want to guess what you do to counter the mid/high problem. |
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I for one have owned the gamut of amplification (including several class D variants with multiple iterations of Hypex and a DIY amp from Class D Audio). Class D was pleasant enough (with a tubed pre-amp), but failed to hold my attention and seemed vaguely flat and bleached for lack of a better description. This common even with those that persevere with it as above. But some don’t hear it, and because they can’t hear it, they say those that do are full of it, even if measurements are backing them up. Bet you thought there was nothing wrong with the bass though . I still believe it is the future, just not yet, I think the Technics and Merrill ones with GaN technology, are going to lead the way, and take Class-D where it needs to be to compete with the hiend linear amps. The others at the moment are great bass amps, but not hi-end yet elsewhere in the audio band.. Cheers George |
I think you misinterpreted this.
Nobody has been building amps with switching speeds that low in a long time Geez Ralph other way around, get with it, in this case I wasn’t talking about 200k switching speeds, I was talking band-width and the slewing of this square wave I posted up, with and without switching noise embedded in it. |
So that makes the scan frequency in this example only 200KHz(!), Wrong again when have you seen an amp that can do 200khz, have a slewing audio frequency square wave like this, the sides are collapsing in like the leaning tower of pizza Our OTLs are quite good at 1 watt 20KHz squarewaves too. And that is where you should stay linear and with tubes, otl, even add trany coupled, so your not hamstrung to certain speakers. You built your rep on them and now your going to destroy that?. Not a good move, it will come back and bite you on the arse, your just another respected amp manufacturer saying "give me some of that class-D action" |
Also, have you (as George is implying) had a religious conversion to the world of class D to the point of implementing it in your products? A fair question, hopefully without the words prototype or breadboarded that no one else has heard. Cheers George |
Zero-feedback Class D would seem to be a unique twist.
Bit late to the party Merrill already did it using the GaN transistors, I believe the SE-R1 does also. Merrill Quote:
Merrill Audio claims that this is by far their most ambitious design mostly because they are using open loop, zero feedback, and zero deadtime with GaN gallium nitride transistors, which are better than most transistors used in other solid-state amplifiers because that have close to zero capacitance, which allows fast switching.
Plus, the gallium nitride transistors can operate in the GHz range. Gallium nitride transistors offer a fast, clean, low distortion power capability", and so Merrill Audio claims that are "natural and smooth in their musical capability".
And after doing this, since the distortion was eliminated, there was no reason to use any feedback at all. He went on to tell me that he is very proud of not having to use feedback.
Eliminating feedback has two distinct advantages. The speed capability is increased significantly and a remarkable gain in the clarity of musical information is achieved. Since there is no signal loop-back, all the feedback loop distortions as well as the attendant time delays are eliminated.
Cheers George |
You sound like your either a dealer or in the manufacturing chain for Class-D, if so which one do you sell, make or affiliated to?
Cheers George |
good Class D is better than several Class A amps. Maybe against backyard junkers. It’s not yet, only in the bass. But soon hopefully maybe everywhere. |
Eric you've tried numerous threads to get this Class-D "praising thing" on a roll, never to keep going, because of the "non acceptance" by way too many for you to counter.
Give it up be happy with yours, that you say you can't hear any problems with it.
And let those that can, and have been down that path go the way they want.
The only ones that are really backing you, are manufacturers that are making, going to make, or selling them in retail supply, they all have a monitory interest in doing so.
It almost sounds like sometimes you asking for acceptance for owning Class-D and listening to it.
I've always said Class-D will be the top dog one day, just not yet, all the detractors (designers and audiophiles) of it have the same common complaint, it's the upper/mids and highs that are the problem, never the bass, this is a done deal showing where it needs to improve. |
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assuming the are the same George who reviewed the Hattor passive pre with a Nord
Sorry you need to do your homework there sunshine, you've got the wrong George I'm afraid on that one.
I'm fine with it if you don't like class D for whatever reasons, just don't tell me it is garbage
No one said it was garbage, I said it doesn't compete with hiend linear amps "yet"!!, one day it will with the likes of the Technics SE-R1 and the Merrill Element 118 now using the new GaN technology that it needs to be rid of it's achilles heel to get there. Cheers George |
Oh and the guy who has done it successfully is only a "semi pro".
Semi "for it" because of his statement. (forest and trees mapman) "evolutionary pathway of audio design that MAY produce even more astonishing results IN THE FUTURE"
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michaelgreenaudio
Thanks for the link George.
That's ok Michael, here another little read you may be interested in, it from the AES Berlin White Paper presented by EPC's (GaN) Steve Colino and Alex Lidow inventor of the Power Mosfet all those years ago. EPC's White Paper "excerpt" on GaN technology used in the Technics SE-R1 and Merrill Element 118: "You can increase switching frequency and audio bandwidth to reduce the filtering cost. The choice in optimal switching frequency is always a trade-off in EMI profile, efficiency and audio performance. The ability to use much higher switching frequencies before compromising efficiency allows for a much range within which to make this trade-off. The result is a more optimized audio solution without fear of Thermal or EMI boundaries.
Most importantly, you will be providing, by far, the most realistic listening experience to your customer in a Class-D system." This is why you'll see, Class-D's with heat sinks inside for each channel like the Technics SE-R1, if they've used the higher 1.5mhz switching speed available to them to use with the GaN. https://abm-website-assets.s3.amazonaws.com/ecnmag.com/s3fs-public/embedded_image/2018/02/figure1.PN...I also asked EPC by email what manufactures other than Technics and Merrill Audio are using or developing Class-D amp with their GaN technology, they replied today, other than the two I mentioned, they said: " We are unable to reveal due to the Non-Disclosure Agreement (NDA) with our customers.
But I can assure you that there are several customers globally, developing with
eGaN FETs for Audio applications, primarily due to the benefits it offers." Finally it seems Class-D has stepped it up in a big way in technology because of EPC's GaN technology, and maybe put up a fight against the very best of linear amps for sound quality in the mids and highs, I think they already have that mantle for bass performance. Cheers George |
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aolmrd1241
Here is another GaN amp to add to the list... You can read more about it in these publication reviews http://agdproduction.com/news.htmlYeah?? I don’t know about that one, jury’s still out, till we hear more about it. Looks to me like a bit of a furphy to gain an edge with the tube brigade, and cashing in on new technology. Might still sound great. I ask, why put solid state components inside an old 6550 vacuum tube envelope, bet it’s not vacuum’ed back out and sealed again either. Still it may sound good, just the whole gutted tube thing, stuffed with solid state, and still using all the tube pins as power/current transmitting contacts???? PS: OK he’s shown all his cards, in this statement " Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. “Otherwise a class-D amp just looks like a box,” he said. The amp uses gallium nitride MOSFET output transistors, which Guerra says switch faster and allow the amp to have a noise floor in the -120 to -130dB range. Power is rated at 200W into 4 ohms." Good on him, I think it was a bad move to do it. (must have been an Italian brain snap to do the tube thing, they do make some of the best and worst cars also) Cheers George |
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