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
snarfie. You may have a point as far as availability of parts for an aging Class D amp but honestly like everything else you won't keep it that long. Class D amps may be like computers, always evolving which could render them obsolete in ten years (maybe)) compared to the latest offerings. For laughs I picked up the new Edge A2-300 (Swedish Made) Class D amp, I'm not laughing now. Retails for $500.00 plus shipping and kicks butt at 150 watts per channel with a refined, clear sound coupled with solid dynamics. Excellent performer!
tweak1, I think your right that Class D amps are not evolving as fast as computers, but they are evolving (for the better?) that is why I emphasized maybe as a matter of opinion. Your EVS 1200 is a good example of good sound doesn't become antiquated.
I remember the first Class D amp that was successfully marketed and sold to the public, the PS Audio HCA-2 . Stereophile placed it in their Class A category and a reviewer stated that there would be many more designs to come but he doubted that any of them would sound as good as the HCA-2. Was he right?
Prior to reviewing, I owned two PS Audio HCA-2 units. Sold them not too long after because A and A/B kicked its ass. Now, it's reversed and class D is kicking ass on other classes of amps. It's going to be carnage.
@milpai - The Apollons haven't replaced my other amp yet; I'm still deciding. They and the Bryston 4B3 are really nice amps, so it's not simple. Their gains are different, and since I have subs in the system, it's not trivial to swap one in and the other out while keeping levels constant. Indeed, it's proven to be more fiddling and fussing than I'm up for. The experience gives me appreciation of what audio reviewers deal with.
That said, things I notice about the Apollon amps are
Extremely quiet and neutral
More detail, with none of the etch or glare that can accompany that; for example, I'm pinpointing instruments in ensembles better and hearing lyrics more clearly
The Apollons seem better control the treble, possibly because of less interaction with my electrostatic main speakers
Both the Bryston and the Apollons have great imaging and soundstaging; both have great bass
I have a tendency to listen louder with the Apollons. Why? Is that good or bad? I don't know!
So, it's proven more difficult than I expected to form a definite preference. Maybe that itself says something useful -- I hope so.
@mike_in_nc ,Thank You for the prompt response. Based on what you mentioned, I think you are listening "louder" to the Apollons, (maybe) because they are so clean?! I think that is indeed good.Are the Apollons warm/cool compared to the Bryston? One point I read with great interest was the "electrostatic main speakers". What speakers are those? Class D in general are accused of not being able to handle 2 ohm loads. Does your speaker dip to that level? If it was me, I do not care for numbers. If the amp is able to drive the speakers my speakers to level I like, I am happy.BTW your feedback is VERY helpful.
@milpai - You’re welcome. The "cubed" Brystons run cool, and the Apollons run very cool. I haven’t noticed a huge difference, though the Apollons probably generate less waste heat.
My speakers are a pair of Janszen Valentina P8. Janszen rates them at 6 ohms nominal, 4 ohms minimum. I would imagine that, like other electrostats, they offer a highly capacitive load.
I think the comment that Class D can’t handle low impedance speakers is audiophile truthiness -- it doesn’t reflect today’s technology. Look at the specs of the PuriFi modules, which can put out 500 watts into 2 ohms with 0.0003% THD.
Look at what independent tested current it can do. Compare the "2ohm wattage" to the "4ohm wattage", and see if the 2ohm can come "close" to doubling the 4ohm, if so there’s no current limiting. If it’s similar or lower, then there is severe current limiting/sagging.
@georgehifi -- It doesn’t matter. It puts out 500 watts into 2 ohms. That’s enough for most users. I consider "doubling" an irrelevant factor. Does the amp generate enough power for the intended use? If so, it’s a good choice (as far as power goes). If not, it’s not. By the way, your statement is logically equivalent to saying that if an amp does put out 500 watts at 2 ohms, it is somehow lacking if it provides more than 250 watts at 4 ohms or 125 watts at 8 ohms. Why should that be a problem?
George does not understand class D and even though I have tried to educate him he refuses to learn. I expect some statement now about EPDR. It will be wrong.
Then next you lot may as well just tell us to use this 6000watt!!!!! Class-D Behringer for just $600us.
I didn't say that; I didn't say that all amps are equal, nor that they sound the same, nor that they are of the same quality.
I did say that I fail to see any relevance to this "doubling" business that has become an audiophile touchstone. Those who claim it is important seem to resort to pseudo-technical handwaving. Maybe there is a reason, but I've never seen it laid out in valid technical terms.
And YOU didn't answer MY question: If an amp can put out 500 watts at 2 ohms, why is it important that it put out no more than 250 watts at 4 ohms?
You make it sound like the Wilson Alexia is the most popular speaker on the market. How many of these has Wilson sold?
I’ve owned a lot of speakers over the years and none had an impedance curve that dropped below 2 ohms. If you own Wilson Alexias then maybe the class D amps that have been discussed aren’t the best choice. But if I owned a speaker this expensive, I probably wouldn’t be driving it with an amp that costs well under $10k.
If a linear amp was a perfect voltage source it would double every time the impedance halves. So if it does 500 watts at 2 ohms it will do 250 watts at 4 ohms and 125 watts at 8 ohms. It's not that it's important it puts out no more it's that even if we were talking about a perfect linear amp it couldn't .
You make it sound like the Wilson Alexia is the most popular speaker on the market.
No, I use them as my friend owns a pair, he's reviewer, so we get many amp to try on them, and they are one of the the most difficult speaker to drive,
especially for Class-D, as they have an EPDR of just 0.9ohm in the bass.
@djones51 - if your definition of an ideal amp is a perfect voltage source, meaning an amp with zero Ohm output impedance, then a class D amp gets closer to this ideal than any other amplifier topology. Class D amps have much lower output impedance than class A or A/B amps.
@jaytor - For sure. I wasn’t sure I read the spec right . . . the output impedance of the 1ET400A is specified as <65μΩ @ 1kHz. Sixty-five millionths of an ohm. The output terminals will add more impedance to the circuit than the module itself!
I've actually grown to like georgehifi and consider him similar to an old dog that's just become a fixture around the Audiogon shop. Sure, he barks at predictable times about predictable topics, grudgingly respects and roots for class D while constantly throwing shade on it, poops inside the house a bit too often, probably has fleas and is generally about as useful as nipples on a male mouse. But aren't these some of the qualities that make him so endearing and lovable, too?
It's my understanding that efficiency has been the primary advantage and raison d'etre of class D amps since the get go. Their further efficiencies in weight, size and cost are just peripheral advantages. Their further relatively constant improvements in performance and sound quality are, in strictly technical terms, just 'friggin breasts'!
Evidently, it was too much to hope for some reasonable discussion of the virtues of the Apollon, with perhaps some owners of competing brands like Nord and March contributing also. But so the 'gon goes.
I have a March Ncore P502. It's a very neutral amp which to me is the best thing you can say about an amp. Never heard an Apollon but they measure very well and inside they look tidy and well laid out.
If you think of the number of people on the planet, who are audiophiles or enthusiasts, and among those who own speakers whose impedance dip to less than 2 ohms - that must be 0.01%? Don't know. But for the rest of us folks the Purifi would be more than sufficient. +1 @twoleftears Would love to hear from other Purifi owners experience who own Nord or March.
I had a HCA-2 and still have a PSAudio GCC 250 (moded as new by Chris Johnson) that I bought when it first came out. I then had several W4S models > Emerald Physics 100.2 SEs with upgraded fuses > Audio Alchemy DPA-1> PS Audio M700s, and now, and for the foreseeable future, my awesome EVS 1200, though I am still in line for the Voyager GaN
Stereophile has a very nice review of the $2500 Marantz 30 integrated
I’m with twoleftears, I’m always up for a thorough discussion on all the class D amps that owners think are noteworthy. I’m very satisfied currently with my 6 year old pair of D monoblocks but I’m constantly curious about the latest examples and I’m very interested in reading about opinions on them, whether from owners or those that have personally auditioned them. I became a member here back in 2013, and if I recall correctly, that’s about the time that the newer, very high quality class D amps began becoming available. At that time, I remember there were a lot of forums from owners of various brands of these very high efficiency, small, lightweight and relatively affordable class D amps that were being extolled as also offering very good full frequency range performance. These claims of very good full frequency range performance seemed to be a major point of disagreement on the forums at that time. The class D naysayers were typically proclaiming they were only suitable for bass amplification, sterile midranges lacking body along with bright and fatiguing treble. Even as long ago as 2013, the class D amp advocates were proclaiming many of the latest D amps were much improved, powerful, dynamic with high quality full range performance, including the vary important midrange and treble frequencies, in their systems with a variety of speakers. After reading many of these early forum discussions on the merits of class D amps, I was a bit perplexed and frustrated. Were these amps as good as described by many? Why was there such a polarization of viewpoints, with avid opinions on both pro and con explanations? Were these class D amps, being examples of newer advancements applied to a somewhat older technology, any good or not? I finally realized I was unlikely to receive any objective answers to my questions by simply reading Audiogon and other audio forums about them. So, I decided I needed to just pick out a reasonably well performing and priced class D amp, purchase it on a free 30 day in-home trial basis and determine the technology’s viability for myself in my own system and room. I bought my initial class D amp, a Class D Audio SDS-440-CS high powered stereo unit from a company in California, based on its generally favorable reviews and reasonable $540 price. To state I was impressed by this relatively small and lightweight amp would be a serious understatement. It easily outperformed my 2 prior decent quality and high powered class AB amps, an Aragon and a McCormack, in driving my Magnepan 2.7QR main speakers I used at that time. So I finally had my answer, even a budget class D amp performed very well in my own, very important just to me, opinion. I was definitely impressed, but somewhat unexpectedly, this only made me more curious about the practical applications of this new to me class D technology. As a result, I fairly quickly decided to purchase a few more D amps to see just how good higher priced and quality examples might perform. I next bought a stereo Emerald Physics EP100.2SE unit and then a pair of monoblock D-Sonic M3-600-M amps. My main points? The D-Sonics are the best performing class D amps I’ve used to date, Just like twoleftears, however, I’m still curious about new advancements in class D amp technology in general and I welcome any reasonable forum discussions on the subject. I also suggest, for any others uncertain about the performance level provided by class D amps in general, that individuals don’t rely on taking mine or anyone else’s opinion on the topic. Instead, I recommend individuals take advantage of one of the numerous class D amp company offers, of no risk free in-home trial periods, and just decide on the merits of the class D amp or amps for themselves.
The best measuring class D amp modules at this time are the purifi and Ncore. That's not to say others like ICE or Pascal are not good, most likely they would be indistinguishable in properly designed implementation. As an example the Dutch and Dutch 8c uses Pascal after testing various modules because they could get them for a better price and couldn't hear or measure any difference. I believe Buchardt uses Pascal as well. There is no reason class D amps should be expensive at least by audiophile standards unless the company uses high priced case design, name recognition, added coloration through implementing purposeful distorion by way of tubes etc... , more features like the Nad M33, room correction, dac, streamer.
Then next you lot may as well just tell us to use this 6000watt!!!!! Class-D Behringer for just $600us.
Let
me tell you, that on the Wilson Alexia in an a/b it was trounced by the
40 x times less powerful!!! Gryphon in dynamics and bass control. The
Behringer was thin, anemic, weak in the bass and sounded like it was
struggling
This post is using a Guilt by Association logical fallacy, which is that since the Behringer amp is class D and struggles, therefore all class D amps will struggle on the same load. Logical fallacies are false by definition.
It's my understanding that efficiency has been the primary advantage
and raison d'etre of class D amps since the get go. Their further
efficiencies in weight, size and cost are just peripheral advantages.
One advantage of class D amps that isn't mentioned so much is how they make distortion, and what sort of distortion they make. The distortion is mostly based on the linearity of the encoding system and deadtime used in the output section. A good deal of this distortion tends to be lower ordered harmonics. A second advantage is that if you use a self-oscillating circuit (which is an idea that's been around for about 20 years or so) then it is possible to put far more feedback in the design than is possible (for the most part) with traditional solid state designs. This is how the Purify module is capable of such low distortion. This also results in an output impedance that is so low its pretty difficult to measure. **That** simple fact means that the amp can act as a voltage source into speaker loads that are quite a bit less than one ohm, even if its power supply can't support doubling output power at full power into such a load. But if the amp is playing at a few watts (IOW: normal listening volumes) it will do so with ease.
The initial problem I had with AGD was the gimmickry of the tube enclosure, but I have to say that the pretty much universally positive reviews have brought me around.
As an example the Dutch and Dutch 8c uses Pascal after testing various modules because they could get them for a better price and couldn’t hear or measure any difference. I believe Buchardt uses Pascal as well.
They are not Pascal’s modules, like ricevs fiddles with Ice modules, they are tweaked by Pascal, but are $100 Chinese Sanway subwoofer modules, as I’ve shown before with identical pictures. That Rowland Research and Red Dragon also use. https://forum.audiogon.com/posts/2085585
@tvad , I am surprised that the AGD did not replace your existing amps. They had replaced a reviewer's SET amps in his system. So I was thinking very highly of the AGDs. Would love to hear from you about the differences between the AGDs and the Audio Notes. What was it that you did not like?
Really!! did you even look! A blind man with "minimal" tech skills can see they are the same manufacturers subwoofer modules from Sanway who sold them on Alibaba for $100 each
The modules in your photos are not the modules in the Dutch and Dutch
So your saying you can get a pic of the modules in the Dutch and Dutch so you can post one up???
If not then time will tell when we finally see a pic of the module, if they are not the Pascal M-Pro2 made by Sanway China, that are used in the Rowland Research and Red Dragon amps. We’ll have to wait and see what they are, to see if Pascal are capable of making their own modules instead of using Sanway or any others, as they have done.
Looks very to me, like it could be one of the 50 odd different subwoofer/PA modules Sanway makes, has a very similar layout to them all, time will tell when a pic of one comes up. https://ibb.co/61hrMyJ
The 8c's cumulative spectral-decay plot (fig.6) is one of the cleanest I have measured, especially in the treble! In summing up the Dutch & Dutch 8c's measured performance, all I can say is "Wow!"—John Atkinson
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