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.
Gallium Nitride (GaN) and is poised to uproot the high-end audio world. In fact
Yes as I posted here, these eGaN fets are what Technics are using in their new $30k class-d and with it are able to double the frequency of the switching noise. And therefore able to remove it with low order filters more effectively from the output of the amp, without coming close to the HF audio band with those low order filters effects (phase shifts) and left over switching noise.
2channel8231 postsAre any other manufacturers using eGaN transistors?
No one I know, it's only a small company that makes them, not one of the majors, maybe Technics have taken all supplies. Maybe this is why from what I heard that the $30k Technics SE-R1 poweramp is for privileged few, and pre order, pre pay.
Erik - those mytek DAC/PREs look lovely. I don't need a lot of inputs, but I also listen primarily to vinyl and don't have lots of high res files, so it would seem to me that I'd be paying good money for something that has features I'd hardly use. My other concern is buying a DAC bundled with anything when the tech seems to change rather quickly. Then again, maybe that's less of an issue than I worry it is...
" Yes as I posted here, these eGaN fets are what Technics are using in their new $30k class-d and with it are able to double the frequency of the switching noise."
Yes georgehifi, you were definitely the 1st to post here and link info on the eGaN FETS that are used in the new Technics amp. I recently happened upon an article about the eGaN FETS while on Audiophilereview.com and didn't recall your earlier posts about them.
My mistake and apologies. I forgot you've been saving up for this $30,000 class D amp. Tim
Thanks for starting the thread. Two of my three home setups are now Class D, the third being a much-loved Marantz 2230. My listening room is the newest, a Rogue Sphinx driving Magnepan .7s, with a Musical Fidelity V90 DAC, Marantz 5004 CD player and Pro-Ject Debut Carbon with Ortofon 2M Red. I just think it all plays together very nicely. Auditioning the Sphinx I also listened to an NAD C368, but thought it had just a bit more sibilance and an amplified character with solo voice, which I'll assume is the effect of the Sphinx's tube preamp section. I listen to mostly classical, jazz and acoustic.
My other Class D is -- please don't laugh -- a Teac A-H01 driving Magnepan MMGWs. It's in the living room, and I wanted to keep the music system as small as possible. When I was shopping a few years ago for this setup, the Teac was one of the few small integrated amps that had a good mix of digital and analog inputs and a subwoofer out. It's got ICE amp modules and a Burr-Brown DAC (I didn't need a phono, which it lacks), so I was willing to give it a go for $330. It puts 43 watts into 4 ohms, which isn't supposed to be enough for Maggies, but they sound great. They seem to love being spread far apart - about 15 feet on opposite walls. They don't go very loud, but they don't need to in this location.
Here's the deal: Like I'm sure a lot of people here, I listen to a lot of live music, meaning symphonic or chamber or opera/musical -- unamplified sound, in other words.As far as I'm concerned, if an amp makes a violin sound like a live violin, and a piano sound like a live piano, etc., it's doing it's job - Class A, A/B, D or whatever. That's what both these Class D amps do, and what the Marantz still does as well. I first heard the MMGWs at a friend's home with a very nice, all-tube amp/pre combo with quite a bit more juice than the Teac. But I've never been disappointed in how they sound with my setup.
Nord One SE uses the same components as the Nord One UP, Hypex NCore NC500, twin SMPS1200A700 PSU’s in ourbeautiful sleek Japanese Mono Block or Stereo Chassis. SE comes with Nord Class A Discrete Input Buffer board with choice of discrete Op Amps, Sparkos SS3602 or Sonic Imagery 994 +£30 and Sparkos discrete Voltage Regulators. Choiceof Dual Mono Stereo or Mono Block chassis
these are what i use in the UK driving my soundlabs they sound amazing prices start around 600gbp up to 1700gbp for the top reference monos which are what i use i have heard nothing like them , very detailed , dynamic , powerful but so musical and natural sounding , i have tried half a dozen class D before these , no amp i have heard betters the nord they ship all over the world
In a digital amp the feedback affects the width of the "on" period.
First, I’m not sure that anyone has proven in a linear amplifier why moderate feedback is a bad thing. Second, in class D it is a couple of stages away from the output signal, so whatever arguments you might have made for a linear amp’s feedback I don’t know that they would work at all.
As I understand it, Technics is using more of a feed-forward loop. They analyze the errors with the output stage, and then digitally correct it ahead of time, before the actual power amplifier stage. Talk about a huge amount of processing and signal meddling though. :)
The Technics approach is VERY similar to digital EQ and phase correction if you were to limit the correction to purely electrical, it is identical in theory.
If you go that far, might as well include the acoustic output of the speakers as well and finish the job. :)
Using feedback to reduce distortion isn't a free lunch though, or is it?
From what is understood for years by the guru's of amp design, is that any amp should be designed for as little distortion, low output impedance ect., as possible without the use of feedback. Then to use just a little feedback if necessary to clean it up if need be.
Feed forward in a linear amplifier is very different. :)
In this case, I’m using it more as an analogy or principle rather than a specific circuit design.
While most amplifiers have feedback at the output stage, the Technics does the correction mathematically at the input, pushing the error compensation from the front instead of the back.
For this reason, I think of this as a feed-forward idea, being the opposite of feed-backwards.
Curious if any of you have tried the Pioneer Elite AVRs and taken a serious listen to the D3 Amplifiers. I am pretty sure Onkyo now owns them all. I use them for 2-channel, it is musical, fatigue free, harmonically accurate to my ears. I does lack the warmth and SLAM if my good Sim Audio separates on my main rig for audio. But I have to say that in many respects it is more accurate in coherent at about 1/20th the price :). I can listen to it all day long without issue. Any other receiver I have owned doesn't come close. It maybe just me, since I dont hear much about AVRs taken seriously for audio.
Erik, What a most informative thread you have going here! Thanks to the fellows above who share their take on the progression of the design of amplifiers. I won't be parting with my delightful Dennis Had Inspire EL84 SET anytime soon, but this Class D amplification has come of age and will only get better in the future.
Several of the Class D amps mentioned above are uber-expensive and clearly out of my budget, but likely not for others. This technology will emerge in more modestly-priced gear in time, such as with the Wyred4Sound gear that can be had for a song. BTW, a pal sent me a note recently telling me that he had acquired a pair of Nu-Force mono's and they bested his high-end Pass Labs amp by a fair margin.
I read elsewhere that RF interference can be a problem with these amps, as well as the need for power conditioners and better power cords, so this may be an issue to be aware of. Cheers, Mark
I am glad you are finding it informative, I'm learning a lot more about the marketplace, and happy to find so many sharing my appreciation for the latest amps!
Nu-Force mono's and they bested his high-end Pass Labs amp by a fair margin.
Which Pass labs amps was this, as I've worked on and listened to mainly the NF 9se v3 mono's, and am very curious to know which Pass Labs they bettered, none I've heard so far.
Thanks for starting this. I had just ordered a NuPrime IDA-16 class-D amp when this popped up.
It is a great amp. Many have already described how good class-D can be so I won't go into that. I'll just say I concur.
Anyone looking for an amp owe it to themselves to at least check out some class-D offerings.
It's new and I'm only a week in with about 70 hours on it but my NuPrime is the most satisfying amp I've listened to since giving up my octal tube pre/845 SET amp. No, it doesn't sound like tubes but it so musical and easy to listen to.
I'm using a little HiFiBerry AMP+ that's mounted on top of a Raspberry Pi 3 Model B in our family room to drive some old JBL 4311B studio monitors. The RPi is running Roon Bridge, so it serves as a Roon output. This combination sounds surprisingly good. I have not tried this little gizmo in the big rig, but it's clear that there's fun to be had at all price points in Class D these days.
Hi Everyone, I owned a Rogue Pharaoh for over a year. I can attest to how good it sounds...it was a vast improvement in every way over the Cronus Magnum it replaced. It drove my Magnepan 1.7s very nicely. What I really enjoyed was how responsive it was when tube rolling the two 12au7s in the preamp section. You could really taylor the sound to you music & speakers.
I think we'll all live long enough to see the day when Class D is the only amp used in subwoofs. The little 350-watt plate amps in my Tylers allow for a higher-frequency roll-off that spares the tubes some real heavy-lifting and allows them to concentrate on critical mid-bass, mids and highs where (don't want to start a flame-throwing contest here) tubes still reign supreme. I also have one of those little cigarette-pack-sized 20 WPC Class D Lepais (which always seem to be on close-out for $20 from Parts Express ) that is on 24/7 hooked up to a pair of small $60 Dayton speaks for the TV: net result being an $80 "sound bar" that sounds pretty good and beats anything from Wal-Mart for $<200. (I mean, who wants to waste tubes listening to Judy Woodruff or some ancient B&W movie with a crappy sound-track anyway?)
Subject for another thread, perhaps, but why do the makers of of $2,000 flat-screen TVs include sound that is worst than a 1950s transistor radio? Class D amps seem to be very much more speaker impedance sensitive than traditional A/B types. Knowing that an 8-ohm (nominal) speaker can wander down to 2 ohms depending on the music, I wonder about the effect on Class Ds at high levels with fussy electrostats, for example.
So much in future will depend on execution just as it does now: pwr supplies, the outputs' electrical behaviours, good ol' quality control, the quirkiness of the specific technology and the like. I can just see a snobbery develop amongst transistor types towards Class D amps the way some of my tube-loving brethren hold against s/s/ amps. The ultimate arbiter will be the ear, and we each have a different pair ...
I love my little Benchmark AHB2 amps. They are A/B with class H rails but minimize the distortion to pre-amp levels using feed forward error correction. Ultra small and fast switching power supplies that move the switching out of the range of human hearing. There are a lot of exciting innovations on these. They whip around my Maggies like nobody's business, are crystal clear and are dead quiet even at concert volumes. I don't have to turn them off like my Pass amp. . .
I have 2 PS Audio D amps,they are good enough for me and I have no problems with better or newer technologies...after all it is the sound that counts...
@hgeifman I'm in a similar situation. I just purchased the Bel Canto Ref600m monos and will be driving them directly with the PS Audio DirectStream Junior. The DSJ isn't quite the M1 DAC, but I hear they are both similar in the way they present more of an analog sense of ease and lack of digital glare. I'm excited to get my new setup running.
This setup is an upgrade to my previous pair of Cambridge Azur 851N DAC driving an Audio Research DSi200 which is a class D integrated using a linear analogue power supply. I was actually very happy with the ARC, but it had a passive pre section that couldn't be bypassed to use just the power section. I need a power amp that will allow me to control volume digitally elsewhere in the chain (and perhaps do some DSP/crossover stuff with a DEQX in the future). The ARC amp had awesome drive and really wide soundstage. Everything I read about it online was very positive from 6 Moons, Absolute Sound, etc., but ARC stopped making their class D line. I always wondered why. I can only speculate. It certainly wasn't from poor reviews.
@neil_squires@neil_squiresand Tim, harmonic distortions lower than 0.005% have already been achieved in class D for a few years. One example is the Mola Mola Kaluga designed by Bruno Putseys using an enhanced NC1200 Ncore modules. THe amp is rated at less than 0.003% across the audible frequency band. The big Rowlands M825 and M925 amps also exceed the 0.005% target, but their price tag makes them somewhat more exotic.
The interesting thing in Gallium Nitride transistors is not so much whether they can in principle enable a high priced class D amp like the panasonic to achieve distortions lower than 0.005%, but if the technology could bring such performance in designs that serve the sub_$10K market, and perhaps one fine day, even below the $5K market.
On the other hand, the audible performance of an amplifier is not created by one particular measurement, nor by a slew of measurements, but by the effect -- iuntellectual and emotional alike -- that the device is capable of having on a listener... Plenty of amps of any class can mesmerize a listener, with a somewhat weaker link to their total declared distortion.
Owned 4 pcs mono Spectron Musician III MKII for the past 8 years driving large planars. Never powered down and the music out of the planars is puresex.
I took the Class D plunge just a month ago for my home-office system as alternative to the Triode TRV-A300SE Integrated. I purchased the "Waring" Integrated from FLEAWATT (25 wpc into 4), the owner, Derek makes them himself. This little guy (the amp) uses a TPA3116D2 chip and it's built w/ Dueland cotton/copper wire. My Dell computer (JRIVER server) is connected via USB to a Chord Electronics QX (British version) DAC, then downstream of the integrated, Antero bookshelf speakers w/ a 92 dB sensitivity. Does the music lack, euphonics? I'm not hearing it .... and the sound is impressively detailed and transparent, quite musical while bass extension is excellent and tight. I like it so much, I've got him making me another model~!
I've come to a Class D amp not through any intentional act, but purely though preference for the sound quality. I had tube gear for years, then moved to Naim for about 10 years. I was going to upgrade along the Naim chain until I heard Devialet. I bought a D120 about two years ago, then upgraded to a D220 Pro in December. I've never had better sound in life. Musical and accurate and emotional.
There aren't that many absolutes in the audio world. You can do SS or Tubes well or badly, and there are a lot of approaches to class D amps as well. But I would not go back to Naim or McIntosh for anything. And nobody who hears my system comments that it sounds metallic or artificial. Source quality matters, cables matter, power quality matters, and of course, we all have our own preferences in musical reproduction, But those who dismiss class D out of hand probably haven't heard a good system. Or else they just like the sound of tubes and their particular sonic signature.
I think you are going to be very pleased with the Bel Canto Ref 600M monos. I just got my new pair installed a couple days ago, also replacing an ARC Class D stereo amp, model 150.2. The Bel Cantos already sound great, though I expect they will provide even more improvement with more break in.
My own theory is that ARC discontinued it’s Class D amps (and thereby all SS amps) to reduce and clarify product lines now that it is under common ownership with MacIntosh--ARC to concentrate on tube gear and Mac to do the big line of SS amps.
A well designed Class D amp will bring you in and draw you closer to your music. You also will hear deeper into your music and the details you never knew existed before suddenly appear as if previously you've been listening in a fog bank. My analogy/ the difference would be like looking through a dirty pane of glass as opposed to a sparkling clean one. I own two Class D amps and love them!
phd A well designed Class D amp will bring you in and draw you closer to your music. You also will hear deeper into your music and the details you never knew existed before suddenly appear as if previously you’ve been listening in a fog bank. My analogy/ the difference would be like looking through a dirty pane of glass as opposed to a sparkling clean one. I own two Class D amps and love them!
Odd the opposite of what was heard from the $50K Mark Levinson No.53 Class-D monoblocks
Stereophile's Michael Fremer listens to the ML No 53’s. "Through the No.53s Cassidy’s voice was pinpoint sharp but the reverb, instead of being airy and ethereal, sounded like a hard haze that obscured detail at low levels and became fatiguing at higher ones. As seems to be the case with switching amps, no matter how carefully designed, the higher in frequency the music goes, the more problems there are. That also holds true the more you turn up the volume. Generally speaking, the louder I played the No.53s, the more pronounced the haze. The more high-frequency content in the music—women’s voices, cymbals, reverberant backdrops—the more the haze intruded on and obscured the images, forcing me to turn down the volume."
Georgehifi, price don't always dictate performance and you sir do not have my speakers. Mark Levinson builds conventional amps very well but maybe he should leave the design of Class D amps to manufacturers that have had a good track record of building excellent sounding Class D amps. Class D does require experimentation, careful matching with the right speakers, interconnects, power cords and preamps to get the most out of them.
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