FWIW, I've been using a "Parasound ZoneMaster 2350" class D power amp and "Parasound NewClassic 200 Pre" and have been thoroughly impressed. Matched up with Audiolab CDT600 and Polk Lis15 + Velodyne sub is giving me the best sound I've owned (or can afford right now). Maybe not quite Audiophile territory, but I'm smiling all day as I work/listen from my home office.
High end Class D amps?
Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
510 responses Add your response
This statement is false. The limitation of a class D amp is similar to what is is with any amp- how big are the heatsinks, how much current can the output devices handle, and how much current is available from the power supply. This statement is just by someone protecting their yet to be released Class-D. If you say then put big heatsinks and power supplies on it if you want them to be able to drive the many hi-end speakers with low bass impedance combined with large amounts of - phase shift. (smoke screen, using small form factor as the excuse) Lets see if the yet to be released class-D amp can truly double from 8 to 4 to 2ohms, without understating as many now do the 8ohm to make the 4 and 2 look good, thank god for Stereophile pulling them up (but quietly) on this understating 8ohm wattage practice Everyone knows that Class-D can’t do the wattage doubling act below 4ohms, it’s shown in every "legit independent test review", mostly by not even giving! the 2ohm figures. And certainly not like the better complimentary bi-polar linear amps can, when driving speakers that have hard loads, like the Wilson Alexia etc. |
Class-D wattage instead of doubling for each halving of impedance load actually gets goes backwards when they see 2ohms and worse if there is any - phase angle involved, because they can’t deliver the current like a good bi-polar linear Class-a or a/b amp can.This statement is false. The limitation of a class D amp is similar to what is is with any amp- how big are the heatsinks, how much current can the output devices handle, and how much current is available from the power supply. The output impedance of any modern class D amp is only a few milliohms (the Purifi module' output impedance is lower than a foot of 18ga wire). So it can double power from 1 ohm to 0.5 ohms as long as the current doesn't exceed the limits of the output section. The real issue is the filter; lowering the load impedance lowers the effective 'Q' of the filter, IOW it flattens out the filter response. So as the load impedance is reduced, the 'residual' (which is the sine wave remnant of the switching frequency) will increase in amplitude. For any speaker this isn't a problem as the residual is very small on any competent class D amp. One thing I find reprehensible is the way the big names have added all kinds of tweaks to Putzeys’ design (op-amps, power supplies) that are completely unnecessary, or even cause spec deterioration, so they can charge more.The reason everyone has different input circuits is because the module itself doesn't have one. Its input impedance is about 2,000 ohms- most preamps and sources would fall flat of their face driving a load like that. When you're designing a module, there is only so much gain you can get out of it, and you have to use an input circuit called a 'comparitor' which tends to have that low input impedance. So some sort of buffer is typically needed. You are correct that this can color the sound if not implemented correctly. Bruno of course has a recommended circuit, but its not cast in stone that it be used. |
This is a smoke screen, they are still "basically" the same, with the same glaring problem, upper mid/highs phase shift, because of the "switching frequency noise filter" on the speaker outputs. The only REAL gains so far have been with GaN output devices, and the only one to utilize the 3 x higher switching frequency that they can operate at, is Technics with the SE-R1. And because of it their "switching noise output filter" is 3 x higher also, therefore there is 3 x less switching noise present at the speaker output at 20khz, and then also 3 x less "phase shift" going back down into the audible upper mid to high frequencies. Until other Class-D manufactures have done this, they have clearly NOT turned any corners, but just taken small sideways manoeuvres to make buyers think they are being innovative. Cheers George |
I'm liking my Bel Canto monoblocks. They have all the power and all the detail and none of the coloration and distortion. Works for me. I have used them now with two different tube (valve) preamps. I've used them with my Acoustat speakers and it really brought them to life. I use them now with Goldenear Triton Ones, which can handle but do not need that much power (partly because they have class D amps built in for the low end) and that sounds great, too. Keep in mind that I upgraded from Adcom, if that helps. |
The idea that Class D amps are overly load sensitive was true with early implementations. We are way beyond that now. Take a look at this page about the PuriFi modules. With a 2-ohm load, the THD+N stays below 0.01% up to full rated power. And to those who say, "The only good ones are made by XXXX." Really? You've heard EVERY Class D amplifier out there, and under a wide variety of circumstances? |
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Check out Channel Islands Audio. They offer a 30 day money back return if you don’t like it! https://ciaudio.com/ |
bluorion:"
@noble100 Thanks for the suggestions----I've heard good things about D-Sonic. What preamp(s) have you used with the D-Sonics? I'm not really a tube person--I prefer SS. I've never had mono blocks so that's something I need to check out too.
Hello bluorion, I've used 3 very different preamp solutions thus far in my combo 2-ch music and HT 5.1 surround sound system. They're listed 1-3, with 1 being my 1st preamp solution and 3 being my current preamp: 1. A VTL 2.5TL tube preamp, with a set of 4 NOS (new old stock) Mullard tubes replacing the stock Russian tubes, which had a HT/Pass Thru switch. This was my initial preamp solution 2. An Oppo 205 universal disc player that I incorporated into my system with the main purpose being to streamline my system by reducing the number of components and interconnects. 3. A Mark Levinson 326S ss preamp, which has a devoted input for HT that serves as a HT/Pass Thru switch. The tubed VTL definitely added more dimensionality to the stereo sound stage image illusion and sweetness, warmth and euphonic qualities to the tones, as I was intending and hoping. But I also believe these benefits came at the expense of perceived articulation and a detailed presentation due to a decrease in neutrality and increase in distortion and background noise levels. The very accurate, low noise, low distortion and very neutral qualities of the Oppo 205 definitely added very little, if anything, to the left and right channel signals. Unexpectedly however, the sweetness, warmth and euphonic qualities to the tones were still present but seemed to be more naturally produced by the music rather than any tube-like additions, especially on good recordings. But I noticed the increased neutrality and detailed articulation, along with the decreased distortion and background noise levels, didn't enhance my perception of the stereo sound stage illusions being more real and dimensional as the additive qualities of the tubes were able to create. The very accurate, low noise, low distortion and very neutral qualities of my current Levinson 326S preamp, combined with its very tube-like ability to enhance my perception of the stereo sound stage illusions as being more real and dimensional, has caused me to fall in love with this preamp. No matter which preamp you wind up preferring, however, I'd suggest not trying to overthink the system changes involved with utilizing monoblock amps rather than a single stereo amp. Monoblocks just further the concept and benefits of using separate components in the first place. Isolation is improved and cross-talk is reduced, by placing the left and right channel amplification circuitry in their own isolated and shielded cases. For connectivity, you simply run a single unbalanced rca or balanced xlr cable from each of the preamp's left and right outputs to each monoblock's input. Simple and easy peasy. Later, Tim |
I’m in the amps sound similar camp, especially after doing my own blind testing (which was a revelation). I think the Ncores and Purifis have essentially solved any deficiencies. But one thing I will certainly concede: an underpowered class D amp is a horror show, and you probably need more rated power (since the D amps are not rated on continuous power like AB). But these more recent modules have plenty. I use an NCore module design with my Harbeths and it works beautifully. One thing I find reprehensible is the way the big names have added all kinds of tweaks to Putzeys’ design (op-amps, power supplies) that are completely unnecessary, or even cause spec deterioration, so they can charge more. Even his own Mola Mola seems gratuitous. A clean custom-build, like March Audio, is much cheaper and arguably better-performing than the more expensive name brand versions. Of course you give up the credit behind the warranty (Alan March is a one-man band), but you could get twice as much amp for the money, and Alan’s been around a while. |
tvad:"
@noble100, what module is used in the D-Sonic amps? Do you know? I went to the site, and did a quick internet search and could not fine the info. Apparently in the top of the line model it’s not an ICE module." Hello tvad, My D-Sonic M3-600-M monoblocks are over 6 years old now and are their previous model. Mine use Abletec/Anaview class D modules. Their latest M3a-600-M monoblocks are the same price but use Pascal Pro2 modules, that have switch mode power supplies incorporated into the module. I believe these are the same modules that Rowland utilizes in their Continuum S2 integrated amp. D-Sonic's owner, Dennis Deacon, told me when the M3a-600-M monos first came out that he thought the Pascal Pro2 modules subtly outperformed the Abletec/Anaview modules in my M3-600-M amps. I know D-Sonic's top of the line monoblocks have gone through several upgrades and corresponding model number changes over the past about 6 years since I've been aware of them; from the M2-1500-M to the M3-1500-M to the current M3a-1500-M models. Sorry, I'm not certain about the specific modules they used in each but I do believe they haven't used Ice modules in their top of the line monos for at least 6 years, if ever. I'm fairly certain, however, that Dennis Deacon would give you the details if you called and asked him: 800-862-7998. Later, Tim |
Class D for Bass is the Best. For Upper Bass/Midrange/Treble. I run Orchard Audio STARKRIMSON Amplifers for those sections and an ICE Power AS-1000 Class D Amp for the Bass Drivers (one inside each KEF 105/3 cabinet). All fed from a BAT VK-50SE. The best of both worlds ! Sometimes for fun, I'll run my McIntosh MC50's on the Upper Bass/Midrange/Treble. The difference in SQ is minimal between the Mac and the STARKRIMSON even though the Orchard Audio amp peaks at 300W@4 Ω whereas the McIntosh peaks out at only 70W@4Ω. The McIntosh's however are way more reliable whereas the STARKRIMSON Amplifiers have self destructed both in my system and at a friends house. Such a beautiful sounding Amplifier in such a small package. Add some Voltage Overload Protection on the DC in, and Speaker Short Circuit Protection on the output and you will have a World Class Amplifier that the majors should worry about. |
As a relative newbie can you help me learn by explaining your response in a little more detail? Generally I find Class-D don’t do well below 4ohms, not even the mighty 55kg Technics SE-R1’s. Class-D wattage instead of doubling for each halving of impedance load actually gets goes backwards when they see 2ohms and worse if there is any - phase angle involved, because they can’t deliver the current like a good bi-polar linear Class-a or a/b amp can. EG: Gyphon’s etc. That’s why you always see linear amps driving speakers that present loads in the bass where current is needed down to 2ohm or even less with - phase angles like the Wilson Alexia 0.9ohm etc I have a Hypex NC500 monoblocks 340w-8ohm 600w-4ohm, similar to Bel Canto Ref M600 mono’s, but with bigger linear supplies, not smp. They sound good on some Raven tweeter’ed 2 ways I have here that are 4-6ohm benign load. But put the same amps on my big ML esl’s and they don’t do it at all sonically they go thin and loud. My less powerfull linear Class-A/B mono’s 180w-8ohm 360w-4ohm 700w-2ohm sound much better. Go louder, sound bigger with body, richer, tighter and far easier to listen to, with a huge walk in sound stage where the ESL speakers just disappear, the Class-D’s sound loud also, but like they are being fired at you from a point source and being squeezed out at you. But hey don’t sweat it, you’ve got Maggies, and Class-D likes that load, get some used BelCanto Ref M600 monoblocks they should suit them well. https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifier Cheers George |
I drive my Maggie's. 7's with the Spectron musical MK ll class D amp The company is no longer in business as John Ulrick the designer passed away The amp weights in at 54lbs output is 500watts@8ohm 650@4ohms and 1,200 watts@1ohm/65 amps for 500 milliseconds my tube pre amp is the ARC LS15 To my ears and anyone that have listened to my system are duly impressed, to say the least |
Now I can't say from many AB comparisons as I dont have access to much audiophile equipment here, but for the money I've been very impressed with a Rogue Sphinx V3. Rogue is best known for tube offerings but also does class D. USA made, awesome service. It's an integrated with a true Class A pre amp section. Not sure what your budget might be but at about $1500 it's a deal. Uses Hypex modules in a traditional configuration. Also, Rogue offers the Pharaho integrated with 300 wpc and "integrating a true class A pre amp within the Hypex modules". Its a different configuration/topology but I've never heard any comments on the sonic differences. Would love to hear from Agoners if they have any experience. |
baconboy I always knew the Maggie’s were capable of and the Peachtree makes them sing. Class-D likes benign 4-6ohm loads with low - phase angles, and that's what the Maggie's are, but when the loads get tough, then big Linear Amps come out to play. Cheers George |
I originally had my Magnepan 1.7s paired with a Peachtree Nova Preamp and a 220 watt amp and the results were good but nowhere near great. I sorta lost faith in class D amps and set my sights on a ‘McIntosh level’ amp however my bank account said ‘that ain’t happening’! Recently I upgraded to a Peachtree Nova 500 integrated amp and the difference is night and day. There is a presence and detail now that I always knew the Maggie’s were capable of and the Peachtree makes them sing. Class D amps have come a long way and more power helps too. https://www.peachtreeaudio.com/products/nova500 |
The new NAD M33 has the new Purifi Eigentakt amps that has sound so clear that any distortion is nearly beyond the means to measure it. It’s won several awards this year. I own one and love it. If you’re looking for great Class D amplification that’s said to be “revolutionary” you owe it to yourself to check it out. |
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I would add a couple more brands to those already mentioned by goldprintaudio and roxy54 that I personally own and know are very good: $ Class D Audio $$ Emerald Physics $$$ D-Sonic I used the number of $ symbols to denote general price level, the more symbols the higher the general prices from the brand. The truth is there are a lot of very good class D amps currently available, ranging in price from about $500 to $50K plus. I’m fairly certain more good brands and models will be mentioned. It seems like you’re already aware that there’s generally a wide range of opinions on the sound quality and performance levels of class D amps. Based on prior threads on class D, you’re likely to receive the usual parroted claims of ’it’s only good enough for powering subs’, ’there’s something wrong or missing from the sound’, ’it sounds overly sterile or bright’ and ’it’s not quite as good the best traditional amp types yet’. When I read these type of replies, I usually assume that most of these individuals have obviously never listened to a high quality class D amp and simply just don’t know what they don’t know. I suggest you try to listen to several high quality class D amps, as well as several traditional high quality amps, and rely on your own sound quality perceptions, preferences and judgement. It’s important for you to realize, however, that many good quality class D amps are sold online only and are not readily available to audition at some retailers. But this has its benefits, too, since this has typically resulted in lower amp prices and most class D companies offer free in-home trial periods of their amps for about a month. Just like other amp types, not all class D amps sound the same. Based on the 3 class D amps I own and the many I’ve listened to, however, my opinion is that they all share some similar basic qualities: very good bass response due to exceptionally high rated damping factors, an overall neutral presentation along with very low distortion levels and a dead-quiet background noise floor, which results in high levels of detail and a very realistic and 3 dimensional sound stage illusion. If you’re looking for a high powered amp or amps to drive a pair of inefficient speakers, that are also very competitive sound quality wise with the better class A and AB amps but are less expensive, I’m not aware of a better solution than a good quality class D amp or pair of monoblocks. I was searching for virtually the same thing as you are about 8 years ago, after my Aragon 4004 MKII high powered class AB amp died on me, and I needed a reasonably priced, high powered replacement amp to drive my inefficient, 86 db/at 1 W, Magnepan 3-way dipole main speakers. I bought my very 1st class D amp, a Class D Audio SDS-440-CS stereo class D amp, for about $600 and was amazed how well this amp drove my pair of Magnepans. I remember being stunned that this relatively inexpensive amp, that was about 1/4th the size, weight and price of my former Aragon amp, was able to significantly outperform it in every category I care about while consuming a fraction of the electricity and never getting warmer than tepid to the touch. I was so impressed, I bought an Emerald Physics EP100.2SE stereo and a pair of D-Sonic M3-600-M monoblock class D amps in fairly quick succession, mainly out of curiosity and to explore just how well these newer type amps actually perform. I discovered the D-Sonic monoblocks are the best amps I’ve ever used thus far on my Magnepans. They’re about $2,100/pair, I’ve been using these for the past 6 years, they’ve been powered on 24/7 the entire 6+ years and they’re still performing great. If these are within your budget, I suggest you at least audition a pair of these for a month for free. I seriously doubt you’ll want to send them back for a full refund. Best wishes, Tim |
IMO the components and speakers that you are going to use with Class D amps are very important. I know Merrill personally and I also know Tommy Obrien. Both are dedicated to their products. I have heard them in various systems some that sounded really good and then others that did not impress me. I am a tube guy so I like the dimension soundstage that tubes offer. |
There is only one so far that has taken Class-D and it’s operation to the technology edge, that "could" even better the best Class-A or A/B’s. And that is the Technics SE-R1 that uses linear power supplies, the latest GaN devices, and has taken their "switching frequency" nearly 3 x higher than any other Class-D’s have so far, which means 3 x far less switching frequency residual noise and all important phase shift at the speaker terminal outputs. This 55kg monster has taken Class-D technology to the limit "for now." https://www.stereophile.com/images/styles/600_wide/public/010517-Technics%20SE-R1-600.jpg https://cdn.shopify.com/s/files/1/0258/1705/5311/products/parts_image_540x.jpg?v=1586671330 https://www.technics.com/us/products/r1/se-r1.html Cheers George |
Amps based on the PuriFi modules have received glowing reviews. One example is the NAD M33. There also are some small shops assembling amps from PuriFi and other components. Nord and Apollon are two. I'm pretty sure that 6Moons really liked the PuriFi demonstrator amp. I find it difficult to follow their reviews, between gobbledygook, constant reference to products I don't know, and tiny paragraphs of text sandwiched between huge ads. |
I use Class D Audio for center and surround speakers. They sound great in that capacity. I have another Class D amp with upgraded power supply and two modules bridged for mains, it sounds very good, but I haven't used it for months now since my 3C24 amp came on line. The 3C24 has much lower sensitivity than the Class D, so it's used every day now, so I don't have to adjust my pre-pro (Arcam AV-9) mains channel every time I use my HT system. It sounds great, and at 73 YOA, I figure why not use and enjoy it at all times? Regards, Dan |
I like a valve preamp and Class Ds in the summer. I change to a valve power amp in the winter, spring, and fall. I still use Class D for bass duty, 365. Then an A/B for a servo sub system from, GR.. It runs pretty darn cool on all Class D. I like Nords Buffer boards. I also like Sparco 2590 pro chip.. mids are WIDE open with that op amp..and the highs won't blister your ears if your into hard domes. I'm not... Do they sound better than my Cary V12r, NO. Man I got it sounding special.. For monitor duty, ONLY NO BASS. BUT the Class Ds, are pretty darn good.. BLACK background.. I love um.. Mac, Pass, Mark L, Ampzilla, Accuphase, I've had a few... Class Ds are the Bomb.. Regards |
I have replaced a pass lab 150.5 , Bryston 14bsst and adcom 5800 that powered my 5.2 system with all class d. Not only does the change sound better but no heat problems and using less electricity. Much happier with smaller footprint an not having to move 75lb slabs makes moving things around a snap. I have hypex n core 400 mono blocks for surrounds a EVS 1200 for mains and a dual hypex nc502 amp bridged for the dual subs. A lot more juice for a lot less money that in my opinion sounds better. |
I don’t have experience with those integrated amps, but I think the character of the preamp will be preserved using class d. I think a nice tube pre and a class d amp would be great. For me it was all about whether the speakers will respond to the additional power. My McIntosh was going into protection mode more frequently than I liked and that was an additional incentive to try class d. My wife complains about how loud I play my tunes. Lol. I also like having a back up amp in my main system. Don’t be intimidated by the naysayers to try class d. |
@flatblackround Very interesting---I wondered about something like that. Using a high end integrated like a McIntosh or Luxman as the preamp and using a class D power amp. Like using an Accuphase integrated with a Bel Canto amp for more juice? Will it sound that much different than using the integrated alone? |
