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.
So, I’ve been pondering and studying class D, from the layman’s perspective (I’m no electrical engineer, can’t solder, can barely find the transformer), for several weeks. I’ve particularly reviewed Wyred4Sound, D-Sonic, Class D Audio, Apollon, Nord, VTV, Emerald Physics and others. I was excited about purifi and discovered a very good deal on the VTV website, but then when I called out for reports on VTV, as little can be found online, I was immediately met with a critical review, claiming that VTV did sloppy work on the purifi amp this person ordered. I came away concerned that I might have to ready myself for repairs, on a new amp, which this other gon’ers amp required.
So, here’s the deal... I have a new pair of Tekton Moabs, which at 98db are efficient. I’m using a Schiit Saga (tube+passive), as well as a Modi 3. I also run a Nuforce STA200, which is delightful for most listening. Unfortunately, it does not pound out the lowest notes when needed, and when I push it into 90db and up, it quickly heats up to a point where it’s obvious the amp is struggling. I want a cool running, efficient amp. I’m sure tubes would sound great on the Moabs, but we hit 93 today, and 105 (and higher) is just around the corner.
...and so, to conclude: Do you have a recommendation for a class D amp that would match well with the Moabs?
I've had a pair of PS Audio M700s for a couple of weeks now; I understand them to be "Class D." They're very good. I think I prefer the Belles 350A Reference (at least in my room, system, etc.), but I could never say the M700s aren't terrific sounding.
You are kind of hitting on a topic I’ve written about here for a bit, which is habit, taste and training our brains to appreciate different things.
For whatever reasons, my brain is wired quite the opposite. I don’t like the sound Pass amps make and often prefer other brands, and many Class D amps.
There’s no right or wrong, you can’t convince me to like a Belgian White ale either. :)
This is a fascinating discussion. I love tube amps like made by Canary, I have their 160 wpc monoblocks and I am thrilled with my Pass Labs x250.5 amp paired with Don Sach's preamp.
My brain does not appear to be wired in a way that class D amps sound good to me. Hopefully the technology will advance and I will have another amplifier type to lust after, collect and rotate thru my systems.
Just got my first class D amp, based on the Purfi 1ET400A. I have to admit I am pleasantly surprised with the detail and just boogey factor this little amp does.
Every time I see a thread like this I remember a scene from the movie Gettysburg - "I take men one at a time. Anyone who judges by the race [group] is a peawit."
So it is, I think, with Class D, or A, or B, or any other variant.
Yes most techs will not repair Class-D down to component level, too time consuming and difficult to trace faults with these surface mount, multi-layer boards class-D amps have in them. Because everything is is so tightly packed, so they can squeeze them into mini chassis. They just want to install complete "expensive" new board/s. Trouble is many of the manufacturers don't have old model boards in stock.
Class D is not digital and there are no "digital" parts in the amps. Class D uses chips that are easily attainable and will be around as long as parts used in Class A amps. Here is the rub......if your class D module breaks then it is usually replaced by another module. They are designed to last years and years and they are inexpensive enough that they can be replaced relatively cheaply. However, if you paid $2000 for a class D amp today and one of its modules died 10 years from now would you even have it replaced for $300 or would you rather get the latest $500 amp that sounds even better.....they will get better and better and cheaper and cheaper. This is, of course, the same with class A/B amps. Imagine buying a $20,000 class A/B amp today and it goes dead in 10 years.......by then you could probably get a $2000 amp that sounds better.....so just have the old amp fixed and try and sell it to someone. We are reaching the end of the "You have to pay thousands and thousands of dollars to get great sound game"
Now if you have an amp designed years ago by someone now dead and there are not any schematics for it (for instance Spectron Audio....makers of class D amps from 20 years ago)........then good luck trying to get it fixed. So, just junk it and buy todays even better sounding class D or class A/B amp for less than what you paid for the Spectron......not really a big deal unless you are really cash tight.
Here today gone tomorrow world of digital parts and design would make me seriously think about putting serious money into a product that may have obsolete parts in the future that aren’t available.
I have to say the modules I’ve seen were barely serviceable. I like the sound of the ICEpower modules, but having attempted to service several of them which arrived with broken off caps, it was a real challenge. They are packed tight and with little care for easy disassembly and re-work.
Every other amplifier I've worked on fell apart (in a good way) as soon as I realized where the screws were that were holding it together.
Another thought on class D and design. One must also consider longevity of parts used and future serviceability of current digital parts implemented in its design. Here today gone tomorrow world of digital parts and design would make me seriously think about putting serious money into a product that may have obsolete parts in the future that aren’t available. Unless a manufacturer stock piles enough parts for future service needs your probably looking at Something that’s worthless if it needs repair of digital parts that are unavailable. Even then there’s no guarantees that a manufacturer will still be around to service it.
Nice thread Erik. I bought the ATI NC528 class D amp to replace an ATI 6012. Needed more power for the new woofers in my Linkwitz Lab Orion speakers. The Orions need 8 channels of amp. One for each driver. The 528 has linear power supplies. Someone asked about soundstage depth. My back wall is 20 feet behind the speakers and the soundstage can go well beyond that. The ATI sounds nuanced, has great dynamics and musical ease. Sounds as good as the front end components. Just bought a used phono-preamp. Asked the vendor who is going to sweep that giant soundstage? I used to own a First Watt SIT2. Class A Magic with the right loudspeakers. But the ATI class D with Orions is also magical.
I just replaced a Schiit Vidar with a Parasound Zonemaster 2305 and find it a great addition to my system (and I really like the Vidar!).
I can’t speak to the technology points being raised however for myself Class D gives me a level of performance that I could never afford in a Class A, A/B amp.
Interesting. I would only offer the following on that. The Vidar measures better in many of the specs like crosstalk and frequency range. It also costs about half of the Parasound 2350(I don't think there is a 2305, you must mean the 2350).
I suspect the reason you like it over the Vidar is because it is giving you 3 x the wpc. You could get 400 wpc if you had 2 Vidars, and ran them in mono, for roughly the same cost as the 2350. Different strokes for different folks...
+1 atmosphere Another prime example of the universal principle that georgehifi happens.
Due to the vast amounts of prior fecal matter georgehifi has dropped on this Audiogon Forum over the years, an elite group of the world's best scientists currently believe after completing their thorough analysis of this over abundance of raw data, that this principle can be relied upon to such an exceptionally high degree without a single exception that this Principle merits upgrading to a Law, pending peer review.
If you want to look at another very respected amplifier design that has a residual waveform imposed on the output signal, look no further than the Berning amplifiers. These amps are excellent; they are liked by everyone who hears them. They employ a switching power supply at their output which is modulated (loaded) by the operation of the power tubes. The switching supply thus has the audio signal imposed on its output. The switching frequency is then filtered out, leaving the audio signal to drive the loudspeaker.
If this sounds familiar to those versed in class D amplifier concepts, it should because its a very similar idea!
So how is it that such a respected amplifier as heard by all comers gets a Murphy while class D does not? They both have a residual. The conclusion can only be that the residual is not harmful in either case.
dutch12 I recently purchased a used Belles 150A V2 I never thought class D could sound like this after all the negatives I’ve heard...they just haven’t heard the “right” class D equipment I guess.
Sorry to burst your bubble there Dutch old mate. But the Belles 150A V2 is a 150w Class-A/B linear amp, nothing to do with Class-D. https://ibb.co/yn8f6FJ
And your right the
Belles 150A have a great sonic reputation, probably better than most Class-D, except for maybe the Technics SE-R1. Stick with it you’ll be happy for a long while, till Class-D rids itself of it’s Achilles Heel. Like what Technics did to combat it with SE-R1, but yet to remain affordable as well, instead of being $20K.
I recently purchased a used Belles 150A V2 for my second system and I’m amazed at the sound. The rest of the kit is a Luxman C-300 pre, Cambridge Audio CNX V2 streamer, Ryan R620 speakers and Clear Day double shotgun speaker cables and Silnote Audio Morpheus Reference classic interconnects. Every time I listen I have a smile on my face. I never thought class D could sound like this after all the negatives I’ve heard...they just haven’t heard the “right” class D equipment I guess.
Actually Georgehifi, YOU made the claim the the output of Class-D is not recognizable, and then you compared the switching residue internal or external,
Go back and read a bit more carefully, please🤦♂️.
If the Class-D output filter is removed, then "input test signal" (not switching noise as you say) is not recognizable at the output terminals because of the switching noise monsters it. With the filter in place, it still sad with residual switching noise, but recognizable, as to what’s going into the input.
Well I just picked up a used Spectron MKII to drive my .7's Maggie's. This class D amp was designed my John Ulrick and who was co founded of Infinity with Arnie Nudel back in the late sixties. This amp is a beast and weighs 52lbs! Has all kinds of power and with do 65 amps fo 500 milseconds when needed. The pre I use with it is the VAC LS 15 and I think it's a very good match. Songs that I've listen to for years now have a intensely close to a live event that I've never heard before. At first I thought it was a little on the anilitical side, but now my Maggie's are projecting more inner detail with the proper energy and now I'm thinking at least to my ears anyway very precise and accurate would be more fitting.
For those that wish to see what goes in and what comes out between
Class-D v Linear amplification which is closer to the original input, or
closer to "straight wire with gain" as what was the start of this
But here we see a 10KHz waveform, which is difficult for many amplifiers. Imposed on top is the residual, which is about 250KHz, which is low by modern class D standards:
Note the scale on the left side of the image- its not there! There's no way to tell how strong this signal is, but the residual is a clue; its about 1/4 the total waveform amplitude. Since we don't know the power of the amp, we can't say how high this should be but if its 0.25 that would fit for an amplifier that makes 100 watts. If that is so, the amplitude here is half that of the waveform in the the next image, which is 1KHz instead of 10KHz!
George's attempt to put class D amps in a bad light on this account is debunked.
It appears instead there is an attempt to mislead people by a of slight of hand, which doesn't win street cred. The factor of 10 between 1KHz and 10KHz is pretty significant! In order to reproduce a 10KHz squarewave the amp needs bandwidth past 100KHz. That's hard for most amplifiers, tube, solid state or class D.
George, if you want to show how class D falls right flat on its face, show a 10KHz input waveform and the same 10KHz output waveform **at the same amplitude** of two example amplifiers. Make sure the outputs are shown at the same amplitude as well. Doing what you've done here is not just sloppy, its looks deceitful as well.
the idea that anyone would run one without the filter is ludicrous.
Your scare mongering. No one said run or listen to class-D without the output filter, it said to "look" at it. Whichimplied to see it on a scope as that’s what was being discussed, comparing input wave form to output wave form, far from the same or what your implying.
For those that wish to see what goes in and what comes out between Class-D v Linear amplification which is closer to the original input, or closer to "straight wire with gain" as what was the start of this
The operating principle of a class D amplifier is that it uses a filter to eliminate the switching waveform from the output. In this manner Class D shares the function of the filter used at the output of the Berning amplifiers. In either case, this is part of the operating principle and can’t be separated out; the idea that anyone would run one without the filter is ludicrous.
And then without their output filter, the input wave form will be
unrecognizable from the output, because of the HF garbage, and melt your
tweeters silently in a nano second.
The operating principle of a class D amplifier is that it uses a filter to eliminate the switching waveform from the output. In this manner Class D shares the function of the filter used at the output of the Berning amplifiers. In either case, this is part of the operating principle and can't be separated out; the idea that anyone would run one without the filter is ludicrous.
I auditioned Flying Mole at RMAF several years ago. To say that they sounded utterly uninspiring to me would be a magnanimous instance of audiophilic kindness.
Thankfully, even back then there already were phenomenal music makers running in class D... One obvious example was the Bel Canto REF1000 Mk2, which I listened with immense pleasure at the rame show.
Yeah, I would have to agree, GeorgeHiFi. The ML speakers you tried the Flying Moles with wouldn't be exactly conducive to a great listening experience. Too bad. I was using Mag-Planar that were really fast and efficient. But still eventually went back to the tubes.
coffee-jerk At some point I will have to try the 600M’s.
Yes you should, as they to me and others sounded better than the Belcanto Black mono’s and Ref 1000 mono’s, still wouldn’t put them in with linear hi-end territory driving hard loads especially
I have Bel Canto 500 monos and a BEL mk V. This is my second BEL, and is kind of the ultimate expression of Dick Brown’s old lineup. Back in the 90’s I had an earlier BEL which I preferred to the smaller Krell and Mark Levinsons. It was really kind of a giant killer, at the time. Now, I’m really surprised at how good the Bel Canto’s sound. Depending on the speakers, I prefer the Bel Canto’s ICE class D to the BEL’s class A. At some point I will have to try the 600M’s.
The admins keep removing posts of mine which are factual and impersonal. So I’m going to keep posting smaller and smaller posts to see what exactly it is they are objecting to.
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.
I'm curious why you'd want to participate in this thread, with exactly the same 3 arguments you've made before. Over and over again, especially since it seems to most readers you keep attempting to hijack it.
Is there a new argument? Is there some reason why you don't actually go start a Class D bashing thread and leave this one for those of us who like Class D?
Also, you have been debunked 50 ways from sundown. Over. And over. And Over. By everyone.
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