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.
Thank you you for taking the time to share great insight on Class D amplification. A bit of clarification on couple of things, in your comments,
"Class D tends to be fast, unless slowed intentionally or with a tube" - Are you referring to mating Class D with a tube preamp/Linestage?
In reference to above comment, the end user should be able to reduce "Coherency Distortion" issues with a tube pre as pointed out in your Synergy 2 paragraph, right?
I have been experimenting with Tube/Class D amps in a bi-amping setup with Tube preamp. It hasn't been easy as I intentionally chose not to add any external crossover or gain switch in the signal path.
I do feel I am very close to the attaining that perfect synergy of Tube's lush mid range and Class D's prodigious slam in the low end.
This is a nice thread, hence a small contribution to the Class D information seekers and long with when Class D will have some synergy with the system.
The largest characteristic of the Class D is the low output impedance. This allows a higher damping factor and in turn more control of the speaker. Synergy 1: If the speaker cannot handle the damping, it will cause break up, distortion and hence won't work. Typically softer cones and larger cones will have this issue. This is not limited to woofers only.
Class D is high frequency modulation or switching which is then filtered to recover the original signal. So band bass filters in essence, high frequency requirements and so on. Most Class D run around 400-450khz. This is much higher then the normal audio band of 20khz. Design, layout, placement, even length of similar runs will create RF noise and distortions. So design of the board, and chassis is very important. The high switching speed places a requirement on the transistors to switch fast. However as with all transistors, there is a lag between the command to switch and the actual full switch. This is call the dead time. This has been reduced over the years with faster transistors and also limited with feedback. But it is fast. Hence the apparent speed of Class D also. Synergy 2: The speakers should be able to hand the speed. Otherwise breakup etc. Bi-amping with a tube/classA (for illustration purposes only) on top and Class D at the bottom causes different speeds, creating a bit of coherency distortion, if there is a word for this.
Most Class D amps use switching power supplies. These have higher instantaneous power delivery. Hence can delivery a very high current and voltage in a small package. There is no large reservoir so the draw on the mains is almost as instantaneous as the draw from the amp. Synergy 3: Power delivery which will include power cords. Line conditioners and other filtering devices, including power cords can limit and clearly slow/change the sound of Class D amps. It is best, IMHO, to remove all conditioners and any high filtering devices but you can listen to the differences to determine what suits you and your system the best.
Class D is quite efficient, however it has to constantly filter the carrier signal and hence the coil gets very hot. This is one of the main sources of heat in the system. The transistors are on or off, so very little heat here. While class D is claimed to run cool, it still requires sufficient venting for the coil to dissipate the filtered energy. So it takes a while to warm up and if not vented, can have thermal runaway and early failures. The heat build up is most when playing, not in idle. For example the VERITAS Monoblocks takes up 20 watts in idle, about the power of 2 LED light bulb or low power CFL. Certainly a lot less then a incandescent bulb at 70 watts
Class D tends to be fast, unless slowed intentionally or with a tube (which helps with dead time distortion also). Synergy 4: personal preferences.
Class D with recent large improvements is catching on in audiophile world. There will always be multiple technologies, as there will be multiple personal preferences. The audiophile world continues to improve in the reproduction of the audio signal, and more rapidly it seems these days. We are luckly.
“In times of change, learners inherit the earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists. ” Eric Hoffer
I want to interrupt y'all for a millisecond and make the observation that this is the most positive thread of it's sort in progress on AG at this time.
Thanks, Eric....and all y'all that don't feel threatened by a 'new tech' that's beginning to make it's mark on the thing we love....the reproduction of the music we fill our lives with.
The more support you give it, the better it will become. Twas always thus...;)
randy-11982 posts05-19-2017 9:50amI also saw news on a new Class D amp from Constellation with very high switching freq. - dunno if it uses GaN devices...
Just checked, just the same as everyone else 600-800khz if they used the new GaN semiconductors it would be 1.5mHz, I wish they did, then that would mean supply to the little folk is available. Technics probably have a monopoly on them for now. " Its Class D amplifiers use a special topology with ultra-high-frequency 600 kHz switching"
I will say, for the form factor, the Mytek is really small, even for a digital amp. I'm VERY curious to know what is inside it. :) A scaled down nCore? Pair of Pascal amps???? Hmmmm......my screwdrivers scream to be let loose to see inside. :)
I'm such a fanboy Mytek should send me a prototoype. :)
randy-11982 posts05-19-2017 9:50amI also saw news on a new Class D amp from Constellation with very high switching freq. - dunno if it uses GaN devices...
Very interesting if it does, I thought Technics had a monopoly on them, if so they’d be the first one to start using them, since the Technics SE-R1 started thing off.
I really appreciate your careful reading of the purpose of this thread, not to mention your thoughtful and nuanced contribution to the hobby in general.
I can only hope that the you can contribute as much for others in your life.
My ARC DS450, is a very capable and musical amplifier. I know Arc uses some proprietary parts in it, and has an analogue power supply I believe, or something to that effect, which doesn't make it like many of the other class D amps discussed. All I can say is, that is a shame that many bad mouth this topology.
I will say that it did need a massive break in period. At first, I will admit, it was murky with little air and honestly didn't compare to my hd220, but now I don't miss it at all. Would I like ref 150? Yep, but I think a ref pre to upgrade my LS-17 would be a better upgrade. The DS 450 is an effortless poweramp, that had more than enough resolution, warmth and musicality to get your foot tapping of hairs standing, depending on what you want at that moment.
I think Im descending further into the rabbit hole with this but any thoughts on how the ICE Ncore and Hypex UCD modules stack up against each other? Or has anyone noticed any differences? I know there are many other pieces that produce the final sound but will the different modules have an affect?
i was told by an audio manufacturer that they were told by a supplier that Hypex was superior to ICE. What are everyone's thoughts?
Our Kangaroo some say in plague proportions in Australia is very efficient, a bit like the Class-D, of the distance v speed travelled in the animal world. But is very one dimensional in it's movement and that straight ahead, easily picked off by a Mick Taylor (Wolf Creek) https://www.youtube.com/watch?v=uTUp4IJ_xqQ Cheers George
Atmasphere 5-11-2017 ... you might be interested in a book called ’Born To Run’ by Christopher McDougall. In it, we find out that we are the dominant species not just because of our brains but also because of our ability to run further than any other animal. Not as fast for sure- its well-known that a cheetah is only good for short bursts. Its a fascinating read.
Thanks, Ralph. I’ll check it out. Having run one marathon and a lot of middle distance races in my younger days it definitely sounds of interest.
My understanding is that at middle distances the fastest land animal is the pronghorn antelope, which is found in western North America. According to Wikipedia it can do 35 mph for 4 miles. Of course there are many humans who can go vastly further than that.
And of course +2 re the importance of putting amps and speakers into context with each other, and being cautious before making blanket statements.
On a different speaker I would expect the situation to be reversed. Just saying- its important to include the speaker when talking about what is 'competitive'; blanket statements can get tricky in high end audio.
So very true,So much too matching speakers and amps.
But I think we all know what the others mean by "compete," whether we agree with them or not.
Best regards, -- Al
FWIW dept.:
@almarg , you might be interested in a book called 'Born To Run' by Christopher McDougall. In it, we find out that we are the dominant species not just because of our brains but also because of our ability to run further than any other animal. Not as fast for sure- its well-known that a cheetah is only good for short bursts. Its a fascinating read.
I've yet to see a class D amp keep up with a good tube amp, but that is on my Classic Audio Loudspeakers, which are not well suited to solid state in general . As a result, I'm sure there are those that would say they are 'difficult to drive' despite being 16 ohms and 98 db 1w/1M :) On a different speaker I would expect the situation to be reversed. Just saying- its important to include the speaker when talking about what is 'competitive'; blanket statements can get tricky in high end audio.
This "competes" is not saying anything, as I can "compete" against
Usain Bolt in a 100mt race, I don't think there'd be any money put down on me to win anywhere in the world!
randy-11: "Can anybody list very affordable great sounding Class D amps - say below $2,000 for a stereo pair, and better or comparable SQ to a Sunfire amp?"
I'm not sure if you're looking for a stereo amp or a pair of mono-blocks.
But for stereo amps, I'd suggest: ClassDAudio SDS-470C for $700. I own the model just under this, the SDS-440-CS for $630, and it's a very good performer so I would think the 470-C sounds similarly good with a bit more power than the 440-CS. Not exactly audio jewelry but bargains sound wise. D-Sonic M3A-1200S, 2 x 600w for $1,875. Stereo version of the M3-600 mono-blocks that are very good. D-Sonic M3A-800S, 2 x 400w for $1,475. Red Dragon S500 2 x 250w currently on sale for $1,899 (reg price $1,9999 black in stock but silver temporarily sold out). Very well reviewed and uses dual Pascal class D power modules usually used in very hi-end amps.
For mono-blocks:
D-Sonic M3-600-M 1 x600w for $2,150/pair. I've owned these for about 2yrs and use them to drive my Magnepans with 1,200w @ 4 ohms. By far the best amps I've ever used on them. D-Sonic M3-1500-M 1 x1,500w for $2,750/pair. I haven't heard these in my system but, based on the rave 6Moons review I read on these, they may give you the best performance short of spending $10k+ on the excellent Merrill Audio Veritas monos. Use the highly regarded Pascal power modules. Red Dragon M500 1 x250w currently on sale for $750 each (reg price $800 each black in stock but silver temporarily sold out.) Very well reviewed and uses Pascal class D power module usually used in very hi-end amps.
There are others I haven't heard such as the Nord monos from the U.K. and the James Romeyn Hypex NC-400 mono kit amp builds in Utah
I shouldn't have bought them since my main goal was to upgrade the speakers. I have too much equipment right now and need to Get rid of some excess stuff. I really like the Meraks and will have to determine what stays and what goes.
These Auralic Merak, (linear power supply and Hypex D-amp modules), you only just got them 1 month ago?? Going back to the Parasound A23 that you have?
Check out the Auralic Merak mono block Class A/D amplifiers that put out 400 watts per channel into 4 ohms. Google the reviews. These sell for $5000 for the pair new. These are the best sounding Class D amps I have heard, and can be had for under $3000.00 used. Often for less than that.
I'm reluctantly selling my Meraks so I can raise cash to get new speakers.
First time Forum responder...aged audio dude...amps along the path include modded Electrocompaniet Ampliwire II (1980's start of good sand amps) ...modded Moscode 300...Muse 160 and now the direct digital NAD M2 integrated ($6K) with full Marigo dot treatment and fuse upgrade. Small room with Salk Veracity HT1's (sealed for added detail) & a pair of Paradigm Ultracube 10 v.2 sub woofers, also Marigo dotted. I was raised in a household of live music, nearby cousins becoming professional musicians. My musical "truth" is instruments and vocals sounding as they do in real life, without amplification. In a hi fi, it begins with good electricity..good grounding and dedicated lines with good outlets. I've been exposed to uber systems, including Volti Audio, better new Marigos, large Kings, Emerald Physics, Tannoys... plus. The NAD M2 simply BRINGS IT! with refinement, depth, stage, air and full slam of the expensive stuff. Without the Marigo dot treatments, things were a little bit "hi-fi" sounding, a bit dry accompanied by that detachment that can happen with digital sources. My audio niche is finding great stuff on a reasonable budget, and making it come more alive with ancillary upgrades. I have several audio buddies who have gone from excellent tube and SS amps to versions of the NCore amps without looking back. The time is here. Pinthrift
I bet the NuPrime/Amphion combo is excellent. I'm a month in with my IDA16 and I love it. I'm using it with Bowers and Wlikins 683 S2s. With the sound I'm getting I have to believe the DAC in it is outstanding as well. Yeah, the feel of the buttons on the remote and the front panel are lacking a bit but they work very well. The volume control on the IDA-16 is fantastic, it tracks beautifully.
I agree with you. There is nothing fatiguing about it . It is refined and powerful.
I saw a Nobsound TPA3116 mini power amplifier for $40, so I figured, "Just how bad could that be?" and along with a 24-volt PS for another $10, I was surprised how GOOD the little box sounded, when hooked to my Large Advent Loudspeakers (circa 1975, new foam rings in 1990).
I tested the set-up with a broad range of musical types-- Jazz Classical, Rock, Live Rock, and I was impressed for a $50 Class-D chip amplifier.
Then I plugged the harman/kardon 330i back into the system, and there was no fair comparison.
My conclusion was the Nobsound (which I might add can be bought from another vendor for as little as $25) would be just fine for the garage, or a workshop, with a pair of small speakers. At that price point it was acceptable, listen-able, and surprisingly small. At 90% efficiency, the power draw for the wall-wort would be negligible.
No sense in trying to compare it to some high-end exploitations of the Texas Instrument chip, but in the right circumstance it wasn't THAT Bad.
Unfortunately, folks like to make blanket statements like "Class-D is inferior"... but that is the same as saying "I like Limes but not cherries"...
I see that Professionals have embraced Class-D in PA systems, and some high-end applications are very good. If this technology is like other aspects of progress, in 5-years we will marvel at what amplifiers might look and sound like.
Anyway, as the "Computer Audiophile on the Cheap" -- I gave the Nobsound a fair trial, and deemed it to be just fine, if we are NOT talking about Audiophile listening.
I admit, being unable to best a 1980s era radio receiver is a very tall standard to eclipse, but I didn't want to send it back for a refund, so I will find it a home...maybe hot-wired to my 24-volt power wheelchair, a pair of cheap speakers, and an MP3 player. I can sound as 'Bad' as the folks with external speakers on the cars with huge rims...
@samac I recently acquired a Nuprime IDA16 and I am very impressed with it. I am using it with Amphion Argon 1 speakers in my office. It is still improving, but I agree, it is a remarkable amp, and a remarkable bargain. I'm not thrilled with the remote, or the front panel buttons, but in terms of sound quality. it is very, very strong.
And on topic, it is nowhere near metallic, or fatiguing. In fact, it is already a much more .... easy, amp than the Hegel amps I've listened to. I don't understand any of the technical stuff, but my class D amps, the Nuprime and my Devialet 220 Pro, are outstanding. Dandy? Yes.
Hi Ralph, Having an integrated with a preamp section as wonderful as yours with a Class D output done right would be a match that would produce big sales.... Just putting that out there, but I'm sure that you know that. Good Luck Brother, I look forward to what ever new comes our way from you. Tim
Sorry- I've said as much as I can offer at this point: 1) its not a module but our own circuit 2) it looks like we have something to contribute in terms of technology.
Atma, I understand now the reason behind the technical discussion on line stages... Very exciting that you are working on an amp project based on class D. Please do keep all of us posted!!!
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