great quotes, all of them. I guess there have been members of the Flat Earth Society since time immemorial…. Luddites of the world unite!
Class D amplifiers. What's the future look like?
I have a number of amplifiers: Luxman C900U, Bryston 4BSST2, Audio Research VSI 60 Integrated, NAD C298 and some other less noteworthy units. As I swap them in and out of my main system, I've come to the conclusion my very modest NAD C298 is about all I really need. Granted if I had extremely hard to drive speakers, I might be better with the Bryston or Luxman, but driving my Harbeth 40.2 speakers, the NAD is just fine.
I thought a while ago that class D would quickly overtake amplifier design type mainly due to profit margin which I think would be much greater than A/B and tube. I'm not saying the other design styles would go away, just that D would be the most common style.
Clearly my prediction is not panning out, at least in the mid and high-end audio world and I'm wondering why? It seems companies such as Bryston, Luxman, McIntosh, Hegel and so many others are sticking by A/B. I'm no "golden ears" guy, but is the perceived sound issue(weather real or imaginary) still holding D back? Maybe my assumption of profit margin is not correct? Maybe the amplifier manufacturers are experimenting with D, but keeping tight lipped until release? Perhaps brand loyalists don't want change similar to what happened with "new coke". What else am I missing?
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@deep_333Res ipsa loquitur
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Steeeerike one!
Steeeerike two!
Steeeerike three! Yerrrr OUT!!!
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@grannyring I'm wondering if you can please extoll the virtues of Lyngdorf's approach to Class D, as it relates to this thread? And, hey! by the way ... tysm for the slick custom mods on my 2170! |
No you did not understand me at all sorry... I never said that bigger cannot be better, with or without pre-amp... I never said that upgrading is useless... I never said that costly design are not often way better... I said that BEFORE thinking about bigger, upgrades, and costlier options, we must LEARN about acoustical, mechanical and electrical embeddings and also about synergy and optimization (tweaking ) ... We must learn about our own acoustic experience UNDERSTANDING ... Because beside the "law" of diminushing return there is another principle i name M.A T.S. : minimum acoustic threshold satisfaction... my own system is under 1000 bucks and i dont need anything more...Not because it is the better , it is not, but it is so well optimized and so well embedded that it put me in sonic heaven... It takes me years to understand with experiments in a rooom how to embed a system... its pay now... I listen music with a relatively good timbre, with minimal spatial soundfield characteristics definition and actual immersiveness level optimal for the price... I compute that it will cost me 10,000 bucks to upgrade my satisfying 700 bucks system , nothing less... I dont need it because lost in music i am able to forget sound without being bothered by any too evident limitations... I called that a rightful embeddings in the three working dimensions for ANY system at ANY price : acoustic, mechanical and electrical...
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@deep_333 I've seen that list of quotes before. They got debunked due to their age. A lot of those quotes you listed are from nearly 20 years ago. At that time I was of the same opinion as seen in them. One way you can date the quotes: look at Thorsten Loesch's comment about a 300KHz switching speed. No-one has made class D amps with that low a switching speed in a very long time 😁 So these comments can be discounted as simply out of date. Your comment about GaNFETs seems a bit uninformed to me. Its not that GaNFETs are somehow 'the answer' so much as when they started turning up was also about the time that class D got a lot better figured out (and that was ten years ago...). There's long been a tubes vs solid state debate on the internet, older that the internet itself. All technologies improve in time so one can safely conclude that sooner or later solid state would get good enough that tubes would simply be eclipsed. To tube aficionados like myself this also means that that new technology will eclipse solid state A and AB amplifiers as well. I cannot speak for other manufacturers, only myself and that should be taken with a grain of salt since I am associated with a manufacturer. I've made no secret that I replaced my triode class A OTL amplifiers with a set of class D amps about two years ago and I don't hear any tradeoffs whatsoever. The class D amps are every bit as good and better in some ways then the OTLs. FWIW, the OTLs have been getting rave reviews and awards in the high end press since sometime in the 1990s. As a result I'm of the opinion that class D is something to be reckoned with and isn't at all as you described; it dominates what we in the high end audio world call 'mid fi'- stuff you get at Best Buy and the like. Its been making inroads into high end the last 20 years and at this point, seems evolved enough that any manufacturer of amplifiers will be going out on a limb if they don't get class D figured out. Its that simple. |
Can someone please explain the wire with gain concept? My understanding is that it's both a pretty cool and also a novel approach, but I'm not real hip to the technical stuff, esp the Pros and Cons. I rely on the opinions of others for that. This thread appears to have some of the most well informed members, tho. For what it's worth, style is actually not only something that I take into account, but it's part of the reason I moved in this direction. I personally find the Lyngdorf style to be sexy as hell and it goes along with my decor beautifully. Very modern and cool with clean lines and not only does it only have 2 knobs on the front ... the action on the volume knob is totally freaking cool. : ) |
@soix LMAO Pretty hilarious! |
So, if I understand you correctly @mahgister then the idea that the old school separate pre amp and amp approach being "better" would sort of fall under the bigger is better type of logic, as well? I've only had my tdai 2170 for a little less than 2 weeks but so far the biggest trade off I've been able to observe is something I read about in nearly all of the reviews is what I can now confirm as the blackest background ever. I'm sure someone's gonna show up lately to dispute the virus of the approach, which I understand very little about b/c I have zero interest around the subject matter, But plenty of our members do! And I know not everyone around here is into the high end cable thing but I'm a Nordost kind of guy, which is a very freaking expensive habit so how nice is it to be able to cut out some of that cost ... as another true trade off of the approach. so far, the trade offs are sounding pretty sweet! |
Dogma run amok. Anyone who values and respects the opinion, experience, and knowledge of @deep_333 over @atmasphere please raise their hand. Joke. |
The "Law" of diminishing return which is not a law but an observation had two faces: a subjective side and an objective side... The subjective side is related to our own acoustic history and learnings and limits in qualitative discerning power and abilities... The objective side of this observation reflect the ALWAYS NECESSARY optimal trade-off choices or the non optimal one , introduced in the audio gear system by any components design limits when embedded in a room optimally or not and coupled with other design reflecting other trade-off choices too ... Most people confuse this two correlated side of a problem with a "law" which anyway is not a law but an observation about the psycho-acoustic subjective factors and the objective audio design factors, they reduce or simplify it for everyone with a negation of the alleged claim that " improving" or "upgrading" ONLY the gear will NECESSARILY improve the acoustic and psycho-acoustic experience, most people reduce and simplify this observation even more when they say that the hypothetical claim about a direct linear link between price and acoustic quality experience is false ... This observation , called improperly a "law" , is a very astute and true observation of a complex psycho-acoustic problem coupled to acoustic and physical material electronic design ... ... |
@inna are you familiar with the law of diminishing returns? |
Those quotes have little value with out a date. In my opinion any criticism is welcome, but it would be more helpful if it were based on listening to actual, specific components, not a google search. And did you have to make fun of the Special Olympics and athletes with disabilities as a way to criticize class D? Not cool. Many of those athletes are more more fit and better athletes than 99% of the general population. |
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Bob Carver
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I’ve been wanting to try Class D amps for a very long time - for energy efficiency and heat management (I don’t have AC). I put it off for years because I was concerned about some of the criticisms. I was convinced after Ralph said his Class D was as good as his tube amps, and also after reading some of the AGD reviews and reading about Alberto’s history.
I just got the new AGD Duet monoblocks - I went with AGD because I wanted the extra power, 300 watts at 4 ohms, and because of the possibility of upgrades as the technology improves. I’m still breaking them in but they already sound great. My other SS amps are the Pass INT-25 and the Boulder 866. I’m in the process of putting together my "retirement" system and I’ve made a LOT of recent changes, so I don’t want to try to compare the AGD Duets to the Boulder 866 yet, but my initial impression is that, in my system, the AGD Duets are certainly as good as and possibly better in some aspects. I’m using the Playback Designs MPS-8 CDP/DAC with balanced interconnects connected to the Duets and using the PBD volume control, driving YG Hailey 2.2 speakers. At some point I’ll put the Boulder 866 back in for a comparison, but my plan is to keep using the AGD Duets with the YG speakers and moved the Boulder to a second system. Alberto has been great to work with and I highly recommend checking out his web page that has info on his designs and his test results. At some point I also want to try Ralph’s Class D amps, and it would be fun to compare them to the AGD. If anyone in the Denver/Boulder area has the Atma-sphere amps, I’d be willing to get together to compare them. I’m glad I waited this long, but I do think now is a great time to try the AGD and Atma-sphere Class D amps. |
@atmasphere THANK YOU for that explanation. Now it finally makes sense. We are not "doing" Class-D "just to be doing it" for the fun of new technology - there is logic behind the "why" of doing it - which is to achieve lower distortions in the audible range, to make music sound more like music. That answers my question perfectly. I visited your website. Beautiful amps. Good luck going forward. |
@moonwatcher Class D offers something that is very hard to achieve with A and AB amplifiers: a very high value of Gain Bandwidth Product. Most solid state amps use feedback, but as you might know, feedback has gotten a bad reputation in high end audio, not because it doesn’t work, but because it usually gets poorly applied- and so causes distortion of its own, adding many higher ordered harmonics (to which the ear is keenly sensitive and interprets as harshness and brightness). So the answer is pretty technical. One reason feedback has this bad rap is because when the GBP limit is reached, feedback decreases on a 6dB slope and perhaps faster with succeeding octaves. This can and does happen as low as 1KHz, so distortion will begin to rise- putting higher ordered harmonics in the most sensitive region of human hearing. What I’m talking about here is easily measured: distortion vs frequency. When you have enough GBP, distortion vs frequency can be a ruler flat line across the audio band. This allows the amplifier to be smoother in its presentation, with greater detail at higher frequencies (since distortion obscures detail) without harshness. Smoother and more detailed at the same time is a good thing IME. Class D makes an enormous value of GBP available to the designer. So you can run very high amounts of feedback without getting into trouble; we’re running 10x more than conventional A or AB amplifiers. This makes possible an amp that is smoother and more detailed than conventional A or AB designs (even in tube embodiments), eliminating the benefit that class A used to offer. The reduced heat, reduced size, weight and cost are all nice side benefits. |
@moonwatcher Yup. My sentiments exactly. BTW I recently spent $$$ doing full upgrades of my McCormack amp (Class A/B) but came very close to going with a GaN amp. Came down to that I really liked the sound of my amp and the prospect of significantly improving upon that with SMcAudio upgrades just seemed like a low-risk option sound wise while switching to a different amp/technology might just end up being trade offs instead of a total upgrade. The devil you know…plus the upgrade was considerably cheaper than the GaN amps I was considering, so there’s that. It’s a journey fer sure. |
@soix thanks. I'm glad it is improving if this is the "future" of what sonics we will have. I'm 65 and likely won't have to worry about it, but I hope it will get better and better - at least as good as the best Class AB amps are, and if the transfer function can be attained that gives them a touch of "tubiness", then all the better. |
@moonwatcher Because it keeps getting better and better especially with the latest GaN and Purify amps that are being compared very favorably to top solid state and even tube amps. When Ralph at Atmasphere not only designs a GaN amp but chooses to use it in his own system over his very highly-regarded OTL tube amps and that avoids all the expense and heat of tubes in a much lighter and more compact design it’s hard to deny the technology’s merit and future potential. Plus, at least in the case of the Atmasphere and AGD amps, they’re upgradeable as the technology continues to improve. The times they are a changin’ and ignore it at your own risk. |
Dropping back and punting. Just the basics. Why is there this "push" to Class-D in the first place? What do you gain? In what way would they ever be sonically better than a good Class A or AB amp? |
The non- modified Peachtree GaN 400 is a beautiful , lush, full sounding amp that is smooth and detailed at same time....BUT....use a Tube Preamp....Thinking about Ric Shultz's modding this amp but it's soooo sweet as it is..When you win the Lottery, get an Aavik with the Pascal module.....That's another world. |
I believe direct digital amps are the future. With regular class D you need a DAC and maybe a preamp. Direct digital amps are not only simpler but purer sounding. The modified Peachtree GaN 1 is incredible. Best sound I have heard.....and cheap. Modified streamer into this $1800 (with mods) thing and you are in for serious sound. The Mark Levinson (Daniel Hertz is his new complany) direct digital integrated amp (Maria 50...$10K) is probably even better. He has written software that improves the sound of any digital source......and according to Steve Huff....it’s the real deal....He likes the Maria amp better than any Class A or other Class D amps he has EVER heard. .please check out these links: https://www.youtube.com/watch?v=TJ2fDLh1NX8 http://tweakaudio.com/EVS-2/Digital_amp_mods.html https://forum.audiogon.com/discussions/peachtree-gan-1-beta https://danielhertz.com/collections/amplifiers/products/maria-50 and for bi-amping and or making your own speakers.......well, this is incredible: http://tweakaudio.com/EVS-2/DIY_Bi-amped_super_speaker.html I think that Levinson will license this technology so other companies can join in the fun.........come on Ralph.....you know you want to try it! NO FEEDBACK.....no analog amplifier circuits....no tubes....no preamps.... no analog cables....this is way cool!
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@inna I don't think if I was trying to fool people that I would last very long- things like that have a way of being found out. There's a very simple way to tell if I've been straight up 😉
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I remember, not all that long ago.... "Class D? Not worth a sh*t...." My, how that’s changed...*s* I’d like to see an amp designed along the lines of my distribution amp, but laid out on the ’style’ of adding a card in a puter.... Want another channel? A pair? More power? 'Dial-able' power? 4 linked as a monoblock?! Buss line switchable to discrete inputs....Independent or mated line level....2>16 ohm outputs...dial up the ’response characteristic’ you’d prefer with the mating pre.... Start from there and dream up the next class... ;) Complain about that for awhile, Then....😏 ...begin to stop ’dissing’ that.... |
It depends on what you are looking for in sound quality. I would love to design a Class D amplifier that outperforms our Class A mono blocs but so far we cannot. No even close. BUT sound quality depends on the design, implementation and parts quality for the component. We have a listening room in Northern New Jersey and everyone is welcome to come and bring their gear in to hear in our systems. We do enjoy the company and meeting new people and are always willing to learn. Happy Listening. |
From the Design Group that did the LSA Warp-1 and the new Emerald Physics EP-600.2SE… we think these $99.50 Wireless, Streaming Mono Blocks are pretty cool.
We like Class D :)
Built for Music and loads of Fun! |
“Class D” as a category is likely to be diffused across newer hybrid topologies ( Class G, Class H) and “digital” amplification in active powered speakers that will obviate the need for standalone amplifiers altogether while adding utilities like room correction. Class D may not displace retro technologies such as tubes, but it is likely to displace A/B topology as performance and combined A/D and GaN FET designs improve. |
We are all lucky to have an expert of this caliber swimming in this little pond... Any attack on his moral standing as a member of audiogon must be counter with vigor... We can loose many other members without loosing much, beginning with me, but no serious audio site can deal with an helpful adviser lost of this caliber... Those thinking the opposite are idiots.. I dont mince always my words... Nor am i always diplomatic,..Sorry... I know you think the same as me ... 😁 Anybody reading his very informed posts think the same... I know nothing about amplification design but i am able to read articles and tech information...
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jaytor thanks for the clarification. the patent must have run out, and that technology has not taken the industry by storm. It did it’s job with essentially no heat in my office, but you are right, I never thought ’this thing sounds great’, just gave me music. Class D must be low heat, do some of them sound 'great'? ................................................................ I know it’s off topic, apologies to OP a bit more about Carver for anyone who cares: The Carver tuner got amazing reception and sounded darn good as I remember. https://www.kenrockwell.com/audio/carver/tx-11a.htm I’m using the tuner in my vintage McIntosh mx110z tube tuner/preamp. It needs a good signal which I have. Sounds terrific. Most people, past and present have never heard terrific FM. Richard Modaferri said "there is nothing I could do to make that tuner better". He designed this McIntosh Tuner https://skyfiaudio.com/products/mcintosh-mr77-mr-77-vintage-fm-tuner-richard-modafferi-serviced-dole |
Be it class D or similar switching technology, it is the future. Linear amps of all kinds will become a niche market. The only good thing about that is the great progress that has been made in both quality of the amps, and in understanding what kinds of DSP can be used to provide the euphonic distortions some prefer. First generation ICE modules were screamingly horrible. Newest Purify very clean. Not to my liking but I can accept the progress. Speaking of Carver. I remember when someone said he could not make a SS amp sound like a tube, so to prove it, he made a very good tube amp, and then tuned a SS to be very close. Not as close as some wanted, but he did make a marvelous tube amp. Silver Seven if I remember. Manley showed us how changing the grid resistor changes the tube sound to be almost SS. The relevant point is that it is the transfer function, not how you get it.
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@elliottbnewcombjr - The Carver amp is not class D. It uses a class G output stage. This is essentially class A/B with multiple supply rails which are switched in based on the signal level, so in most situations, the amp is using relatively low 25v rails. It also employs an unusual power supply design where the primary (connected to the mains) is switched using a triac (similar to a dimmer switch) to minimize magnetic core saturation allowing a much smaller transformer to be used. This design produced prodigious power for it's size, but was not a particularly good sounding amp (in my opinion).
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I think this post is off base. Ralph can use any amp he wants in his system but chooses to use his GaN amp — not really sure why he’d be fooling himself. And unlike some others here he never tries to “sell” his stuff here and mainly just provides very knowledgeable and helpful info to folks on the site and most of the time on topics that have nothing to do with his products. Not sure where all this cynicism is coming from. |
Well, 40 years ago, Bob Carver's Cube was Class D wasn't it?
https://www.hifinews.com/content/carver-m-400-cube My friend Wayne at Harvey's let me know one was coming out of the shop to the used shelf. Like many purchases from that shelf, I didn't need it, bought it just because. Ended up using some inefficient speakers in my office, put that cube in a tight space on a shelf near my head, on for hours, the heat was nearly non-existent, I also has a Carver AM/FM Tuner with his unique features, and ended up with nothing but respect for his mind. Point is, here we are 40 years later talking about Class D. They have been all around us for years, current uses listed on wiki are interesting. Scroll down to uses https://en.wikipedia.org/wiki/Class-D_amplifier I imagine my self powered home theater sub with 1000 watt amp is class D, I sit very near it, no apparent heat. Yet, I am skeptical regarding using Class D in my primary listening setup. I've never heard Class D in a main music system. In any case, I prefer tubes since inheriting (in 1973) a tube unit made in 1958. I only sold those mono blocks (to Steve at VAS) because they didn't have remote volume and I liked the new to me Cayin's sound as much as them. |
After years of reading posts we can distinguish easily honesty and stupidity... Atmasphere is under the label "honesty" for me... it does not means that he is right in all he said but that he put his name on what he said... I believe him , anyway i had no competence in amplifier design...but he is not alone in a desert , others experienced this new types of amplification... Then listening to atmasphere explanation and thinking about it is better than accusing him with no competence to sustain the accusation .. My 2 cent.... |
Ralph certainly needs no advocate to ’defend’ him, but could not stay silent after post that is written above.Whatever Ralphs ’purpouse’ might be, I have learned a lot reading his posts. He even found the time to answer my private msg.about hi fi gear that was not produced by his company. On the other hand, I am quite certain that nobody will find the ’purpose’ of the posts written by ’author’above... |
For my listening needs high quality tube amplification (Low-moderate power genre) is my best option. Simply my individual conclusion, we all differ in preferences. I won’t question another’s motives. Which ever amplifiers Ralph prefers he’s certainly capable of explaining a particular preference. One can accept his rationale or not. Charles
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