I thought it was time we had a pro- Class D thread. There's plenty of threads about comparisons, or detractors of Class D.
That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.
For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.
Nelson Pass's statement on Class-D in an interview yesterday.
"JS:There has been an explosion in high-end Class D amps in recent years. Some companies now market some fairly sophisticated – and expensive – Class D models. Pass currently manufactures Class A and AB lines only. What are your thoughts on Class D?
NP: Personally I think it’s a miracle that they work at all, but then I think that about my phone, too. I have great respect for people who can make Class D amplifiers sound pretty good, and for delivering low cost, high power, and efficiency. They have earned their place in the industry.
That said, I am not tempted to go in that direction."
Uberwaltz, I would have to agree with you. I think we have the same Nuforce amp and I used to have the same Emotiva amps. The Nuforce sounds more like live music than the Emotiva amps ever did. The Nuforce even sounds more live than my Marsh A200 amp or Rotel Class D amp. That little Nuforce amp is small and unassuming but when turned on, it is amazing.
Welcome to the believers! I think the Nuforce and now the Nuprime were/are very underrated class D amps and I have absolutely no intention of looking for a replacement for the ht rig anytime soon. We cannot even get past 50 on the volume without it being literally too much to bear for long. And that I mean in a good way, not that the sq has degraded but just it is more than our ears and room can handle or need to handle.
Seems like there's a great deal of very positive buzz (no pun intended) about the Bel Canto REF600M's, and at 5K/pr they're not in the stratosphere. I wonder how they would sound against a 5K Pass design.
The esteemed Mr. Pass has done so much for the DIY and audiophile community that I absolutely loathe to criticize him or his works in an open forum, especially since he is not the one participating, george is.
Instead, I will only say that you should spend money to satisfy yourself, not anyone else, including me. Listen for yourself. Buy what pleases you for whatever reasons they may be.
I go to bed tonight able to rest because I know every 4th or 5th message in this thread @georgehifi will be raining on our parade, like warm spring showers on a cloudless day.
Wake up and smell the roses sunshine, Class-D is not as Dandy as you try to make out it is YET. I can quote many more just as esteemed as Nelson Pass if you like.
In the future with higher switching frequencies that look to be promised by the semiconductor tech-heads, it very well maybe the amp of choice, then our heavy, gas guzzling linear amps will become door stops or boat anchors.
Class-D today certainly has it's niche in audio, but it can't mix it with the real top of hiend yet.
So i fell across and have enjoyed reading this thread from page 1 - quite the hike. As an entry level audiophile with a passion for both stereo and home cinema and given the title of the thread I thought i'd chime in. Very much an enthusiast I have some basic understanding, have tweaked existing hardware replacing crossover components etc but do not pretend to understand some of the more advanced electronics principles involved in this discussion. I currently have a combination of class A/B and class D both in my car and home and have a mix of passive and active filters.
I don't expect to convince people looking for high end as up to now I have no experience in this domain but it is clear to me that class D amps are capable of some very serious sound and at specific price points can better other alternatives, this I believe is the common denominator for anyone interested in quality audio and the reason for my post.
I stumbled across and am very very pleased with my latest class D amp which happens to find itself inside a pair of floorstanders, admittedly a bit of an exception from most of this thread. I can highly recommend people investigate the Nubert active range, I'm currently running the Nu-Pro A-700
This is a fully digital class D implementation, so is digital up to the output stage, no DAC but a high end ADC for line in, it has the advantages of 3 way drivers with one amp per driver ( 2 x 90w mid and tweeter, 1 x 300W for the 2 woofers) phase correction and group delay as well as frequency response are managed by the onboard DSP.
There is a lot of technology at work here and I continue to be surprised by these speakers every time I listen. I took the risk of purchasing without listening base on reviews translated from a variety of German audio sites, one of which suggests there is currently no better active speaker under 10k€, class D or otherwise. at 2500 euros the pair they are worth looking into and there are other less expensive models built on the same principles.
Here's one of the reviews that show some of the guts:
10 years ago class D had already been around for a while, but back then they weren't bringing home the bacon against the prior art. But it was obvious even ten years ago that it was a rising star.
In the last few years though its become a technology to be taken seriously. So about a year ago we began working on our own design.
Despite this, I can't call it a mature technology, a since price/performance curves define what is mature, and the technology is still improving at a rapid rate.
The major problem, as George points out, is the switching speed, but in recent years that is a problem that is fading. Part of the issue of switching speed has to do with the introduction of dead time, which makes distortion. But there have been a lot of advances in relatively cheap semiconductors recently, and the result has been that for a given switching speed, there is less dead time required because the newer devices are so much faster.
This means also that higher switching speeds are showing up.
Somewhere in this, a threshold is being crossed. We see this with the many responses on this thread. Class D, while like any other technology that has its better and worse executions, has arrived.
Its my opinion that any amp manufacturer that ignores the implications of class D is doing so at their own peril.
Looks like our first patent in the field will be filed soon...
Class D clearly has even more potential although given the article was written in 2014 I struggle to understand why this tech isn’t more prevalent today. Am curious to open my amps and check the components but given the heatsinks present I suspect it’s not based on GaN tech. In any case I smell the roses and class D has come of age.
tweakjunky I struggle to understand why this tech isn’t more prevalent today.
Because mainstream semiconductor manufacturers like Motorola, Hitachi, Sanken ect, haven’t tooled up for it yet, probably because the inventors of the GaN devices EPC (a small company in comparison) I would say have a provisional patent on it, who were if you dig deeper from what I’ve found maybe also the inventors of the Power Mosfet transistor as well way back. And are now maybe waiting for the best offers from the big boys above. Till then they are probably happily supplying in small numbers to Technics for their SE-R1 poweramps.
tweakjunky Am curious to open my amps and check the components but given the heatsinks present I suspect it’s not based on GaN tech.
Only the $20k Technics SE-R1 has them so far, and you need connections to get one.
I have tried a several Class D amps over the past 18 months. I have owned a PS Audio HCA-2, Classe Sigma 2200i, Lyngdorf TDAI 2170, and now have an Esoteric I-03 integrated.
My ranking in in order of preference is: Esoteric I-03 Classe Sigma 2200i PS Audio HCA-2 Lyngdorf TDAI-2170
I can’t imagine ever imagine getting rid of the Esoteric! Wonderful imaging, dead silent, and tons of power. This 68 pound tank blew me away compared to the other three Class D amps I’ve owned, or any of the other amplifiers I have auditioned/owned for that matter.
I am looking at the classe 2200I right now considering a purchase. How did you find its performance on digital sources? Very interested in your thoughts on this
@uberwaltzi used the Classe for all my video sources and my DAC. It worked very well. If I wouldn’t have tried the Esoteric I could have lived with the Classe for a long time. I didn’t use the internal DAC or streaming capability though.
@uberwaltz - I would have liked to tone down the midrange a little from what RoomPerfect picked, but you can’t make manual adjustments unlike the Classe. It just didn’t work for me in my room.
Agreed it might have been better to be able to tailor the eq manually instead of just having the option to change preset curves from neutral. However so far in my room to my ears I am liking it. I performed a 12 point calibration initially and now I cannot bear to listen to it without the roomperfect running as i have way too much bass colouration. Additionally the built in dac suits my needs well, all I would wish for is a little more power but it seems you truly cannot have everything...lol
I just wanted to say I have been pure Class D for about 3 years and I have never, not once thought to myself "I'm listening to a switching amplifier."
Now, are there things I want differently? Sometimes. Can I attribute that to Class D. Nope, not at all.
Before this I was using a pair of Parasound linear amps to power my main speakers. I've never looked back nor gone "wow, I can really hear the slow switching speed distortion."
Now, if I had tons of cash and space, I'd probably have a pair of CJ Premiere 8s (mono right?). Wow, what amazing amps. But that's because they are just amazing amps, not because I need to get off Class D.
I love all the comments but their is really no comparison, class D is not as musical as a class A amps. Not saying that anyone shouldn’t love their class D amps but let’s not fool ourselves into believing they’re on par with a good class A amp. Like I said earlier I paid 12k for a very reputable manufacturers class D amp and it made me want to trash the rest of my system and speakers. It drove me crazy for over a year and then I finally ended up buying a class A amp and now I can’t stop listening to music. It’s like I have my very own personal concert every night.
@bluesy41 - since you haven’t heard all Class D amps I wonder how you can make a blanket statement. If your $12K Class D amp was the Esoteric I-03 and you didn’t think it was musical then I wonder what “musical” is? I own the Esoteric I-03 and the Mark Levinson No. 585 and I they both sound fantastic to me.
I owned Mark Levington, Krell and ARC and their class D amps did not move me the way class A tube amps does. In fairness it could have more to do with it being solid state vs my preference tubes, however the best amp I ever heard was the Ayre MXR 20. So yes an ignorant statement on my part in saying all. I will clarify and say the class D amps I have heard didn’t sound as musical.
I've heard many Class A which I liked less than the Parasound A/B amps, and those are the equal of the Class Ds I have now. I think the idea that all Class A is better than all class D is nonsense.
No offense Erik but I find it hard to believe you can compare Parasound to any highend class A amp for musicality. I get it you love it, but let’s try and be objective. Parasound is a step over Adcom and 20 minutes from extreme fatiguing.
Parasound Fatiguing?? Hahahaa. Some of the warmest A/B amps out there. Run Class A most of the time. And yeah, I've heard _some_ pure class A amps they beat hands down.
Unless of course you measure sound quality by money spent. Then of course, only Class A will be pricey enough for your ears.
To both of you. The Parasound Halo JC1’s in high bias class-a (which is no more than around 20w of A) sounds magnificent, and will blow away any Class-D full stop!!
It seems clear @bluesy41 doesn’t have a clue about Class A Amos. You can’t make broad statements about any amp Class. There are Class A amps on Amazon starting at $500.00 and some of them they sound pretty bad.
The class warfare should really just end. There are very good and very bad amps of all classes. Furthermore one man’s bust may be another’s bounty. That’s how the world tends to roll in general. Deal with specifics not generalized statements that cannot hold true in reality. For example if I designed an amp it would probably suck no matter what Class because I am not an amp designer. Many are very skilled amp designers however and make very good products using their own unique skills to master technology in different ways. Those people are entitled to think their design is best but not at the expense of others. Each buyer will decide for themselves which is "best" for them using all the unique senses God granted them.
Give it up already!
Personally, I’d say Bel Canto Class D amps are one of the best things that ever happened to home audio in my house! They are marvelous sounding modern masterpieces of technology and meet my needs perfectly!
My Lyngdorf 2170 has replaced a BAT VK600SE. Am I happy with what I hear? Heck yes although I believe the room perfect system may have just as much impact on my listening as the amp itself.
Also looking at buying a small Bel Canto integrated for my daughter.
Exactly like the A21 and A23, the the JC1 is high-bias Class A/AB.
(model names in sentence above are links)
Good amplifiers.
Have not heard the JC1, just the A23 and A21.
I have to agree, "class warfare" in this context is meaningless and with little to no supportable evidence. This is what showrooms are for though. Buy what you like listening to, which needs no justification.
Hi Erik, thanks for starting this thread. Another + for class D. Bought a NuForce integrated for a bedroom system. It sounds unbelievably good considering its cost. Without regard to cost, it sounds quite good. A little on the warm side, no sibilant hash, non-fatiguing, pleasant, musical. What more could a sane, rational person desire?
Tom - Yeah, I’m using an NAD D 3020 in the bedroom. It’s a hybrid Class D designed by Hypex, so it runs a little warmer than you’d expect. It’s really quite nice.
One thing I’ve learned recently is NAD is using 3 different types of Class D:
1 - Direct Digital 2 - Hypex Ncore 3 - The Hybrid approach they used in the 3020.
It would be interesting to compare them side by side! I will say that while I am a fan of Class D in general, I’ve never heard a PWM amplifier I actually liked the sound of. I suspect they get the feedback (if any) quite right and can’t solve the output filter issues well.
@erik_squires FWIW the phrase above is a marketing thing. It means that the amp has a DAC as its input, but the amp itself is actually analog, like all class D amps are. IMO/IME marketing terms like this tend to confuse the marketplace.
@tomcarr ’PWM’ stands for Pulse Width Modulation. Such an amplifier usually has something like a triangle wave oscillator in it. The incoming audio is compared to the triangle wave and this determines how long the output devices are either on or off. The switching frequency (which is otherwise determined by the frequency of the oscillator) is then stripped from the resulting signal and what’s left is the audio.
So, with all of this Class D talk, where to the new ATI 52X and 54X rate in the scheme of sound quality? I have read great articles saying how wonderful they are but what about people who have actual experience with them who don’t work for a paid magazine?
In a home theater application will there really be much difference than say running an older parasound or anthem amp?
Thinking of buying the d3020 for my daughter's room and pairing with a pair of epos els3. Sources would be a tt as I see the v2 now has a mm phono input and a PS3 via toslink.
Well I bought a NAD D3020V2 and have to say pretty darn impressed for the money.
Great features include a built in MM phono stage, an additional analog input,a toslink input and a spdif input. Another nice touch is a subwoofer output. Add all that to its tiny form factor, if you cannot find room for this then there is something wrong!
Sure 30wpc is not going to rattle the roof beams but paired with Epos ELS3 speakers it plays louder than I need it to. Oh headphone output as well so very hard to criticize for a bedroom unit or third system which is where it now resides.
$300 shipped as a factory NAD refurbished unit with full warranty.
So, with all of this Class D talk, where to the new ATI 52X and 54X rate in the scheme of sound quality? How do they compare to the D-Sonic and their Pascal modules?
You’re likely getting no responses to your request for sound quality reports on the 2 newer 52X and 54X ATI class D amps because you’re only reaching members who own one of these specific amps AND happen to still be following this long running thread. You may get more responses by starting a new separate thread.
Sorry, I’ve never auditioned any ATI class D amps but I can verify that the D-Sonic M3-600-M class D mono-blocks I own are excellent amps. However, I bought mine about 4 years ago when they utilized Anaview/Abletec ALC1000-1300 class D amp modules. Anaview discontinued the ALC100-1300 modules in 2014 and I believe the current D-Sonic M3-600-A monos utilize the newer Anaview AMS-1000-2600 modules. I think D-Sonic only uses Pascal modules in their top of the line M-1500 mono-blocks. Both Anaview and Pascal are Scandinavian companies and their class D modules differ from most by combining the amp section and the switch mode power supply (SMPS) on the same board. Most other class D module design/manufacturing companies, such as Hypex-Ncore and B&O-Ice, offer the amp sections and SMPS as separate products on separate boards.
I asked D-Sonic’s owner, Dennis Deacon, back in 2014 about the sonic differences he noticed between the Anaview ALC-1000-1300 and AMS-1000-2600 modules and here was his response:
" Tim,
I have been shipping amplifiers with the new AMS1000-2600 modules. The sonic differences with the previous ALC1000-1300 are very subtle with most source material. They do have a more natural resolution of detail and a more natural impact in the upper bass to lower midrange area. This is where most big dynamics are heard such as percussion, cellos, baritone and bass horns."
Here’s the name of that thread that you might find useful and interesting:
I just spent the last hour catching up on this entire thread.
@erik_squires Well done, my friend! You’ve navigated a wonderfully positive thread.
@georgehifi Great contributions throughout. I very much would like to have seen the YouTube videos from EPC regarding their new class D modules for audio applications. Alas, they were blackened out on my iPhone. But I did enjoy your shares about new Gn-based transistors having higher switching frequencies. And your Aussie round table thread from high-end designers was special. Erik might complain about your rain, but it’s welcomed by me, as it seeks to clarify where the class D tech needs to improve. The opinion of Nelson Pass is a good benchmark to base all future commentary. 😂
@atmasphere And yes, the motivation for class D amplification was all about increasing dynamic headroom—avoiding clipping. Yet, as @atmasphere will point out, it’s the first Watt that matters the most and where the class D tech really needs to focus.
As a teenager, I auditioned an Infinity SWAMP, which was a class D amp the late John Ulrick designed and based upon tech that John and Infinity was awarded a US Patent for. I bought a Digital One amp from Spectron Audio (apparently now defunct) in 1997 or thereabouts. I spoke with John numerous times about his topologies over the years. He said the SWAMP design was ahead of its time because the high speed switching transistors really didn’t exist during the 1970’s to make the amp stable. That all improved later in the 1990’s. He later told me in ~2006 or thereabouts that John Dunlavy used the Spectron amps to voice his SC series of Dunlavy speakers. He said that my SCIVa’s mated with the Spectron amp was a magical combination. I only saw one post here from a contributor who had a Musician III amp.
So my question is: how do the Spectron amps stack up in the mix of present class D amp technology? Back in the day, it was a 300WPC 8-Ohm) stereo amp at $2500. I’d appreciate personal accounts rather than speculation.
celander He later told me in ~2006 or thereabouts that John Dunlavy used the Spectron amps to voice his SC series of Dunlavy speakers.
https://www.stereo.net.au/forums/topic/49395-why-are-some-speakers-suited-to-valve-amps/?do=findComm... " I’ve set up Duntech Sovereigns, it is abundantly clear that John Dunlavy designed them to be used with the very lowest output impedance amplifiers available. They don’t even wake up when connected to even quite prodigious valve amplfiers. Even highly capable amplifiers like the ME850 barely get them under control. It takes something like the big Krell monos, or an ME1400/1500 to make them sing."
Pretty sure the Dunlavy SC’s didn’t vary much at all from the Duntech speakers. The SC’s have a nice impedance response (6-ohms). The Spectron Musician III amp has a fairly low output impedance (< 0.1-ohms) and a high damping factor (500:1).
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