I just wanted to make sure you read the data sheet to see that these are indeed GAN devices.
I saw all these when the SE-R1 was released, a year ago and posted them up here. Thanks anyway.
The Truth about Modern Class D
All my amps right now are Class D. ICEpower in the living room, and NAD D 3020 in the bedroom.
I’ve had several audiophiles come to my home and not one has ever said "Oh, that sounds like Class D."
Having said this, if I could afford them AND had the room, I’d be tempted to switch for a pair of Ayre monoblocks or Conrad Johnson Premiere 12s and very little else.
I’m not religious about Class D. They sound great for me, low power, easy to hide, but if a lot of cash and the need to upgrade ever hits me, I could be persuaded.
The point: Good modern Class D amps just sound like really good amplifiers, with the usual speaker/source matching issues.
You don’t have to go that route, but it’s time we shrugged off the myths and descriptions of Class D that come right out of the 1980’s.
I’ve had several audiophiles come to my home and not one has ever said "Oh, that sounds like Class D."
Having said this, if I could afford them AND had the room, I’d be tempted to switch for a pair of Ayre monoblocks or Conrad Johnson Premiere 12s and very little else.
I’m not religious about Class D. They sound great for me, low power, easy to hide, but if a lot of cash and the need to upgrade ever hits me, I could be persuaded.
The point: Good modern Class D amps just sound like really good amplifiers, with the usual speaker/source matching issues.
You don’t have to go that route, but it’s time we shrugged off the myths and descriptions of Class D that come right out of the 1980’s.
201 responses Add your response
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I agree with most here that you can no longer define Class D as a particular "sound" and that the sound quality varies tremendously depending on module selection and implementation. I have Thiel 2.4s and Aesthetix preamps with a Direcstream. An unusually large proportion of Thiel owners (the vintage speakers not the ’new’ Thiel) ended up with Bel Canto Ref 1000 Mk II mono blocks as their amplifiers of choice. For a brief period I used an even older version of the Bel Canto amps: the 300M monblocks. More recently I tried the Bel Canto Ref 600s expecting great things but I was REALLY disappointed. On those amps I heard a recessed upper midrange and slightly rolled off highs. I also tried a pair of Red Dragon monos based on the recent ice power modules as well as one of their stereo amps based on the Pascal modules. Those units didn’t sound bad necessarily, but were in my system rather one dimensional. I eventually ended up trying non-class D amps including the Bryston cubed series and the Pass Labs products and ended up with Pass Labs which tick just about all the boxes for me. In my system the Pass Labs .8 series tonal balance is a little on the warm side but the detail and depth and general musicality of those products is difficult to match. I wouldn’t care if my Pass Labs amp was Class D, Class A, or Class QXZ, I would still love love love what they do. |
@guidocorona "Thank you so much Merrill!" - Most Welcome. "Indeed I had suggested a few small things... I believe that you actually implement my recommendation to use 20A IEC to maximize stability of connection with heavy power cords.... Well, at least now, if anyone complains about 20A inlets, you can refer their lamentations all to me *Grins!*" - You are rather modest. You have more other subtle contributions which I have valued over the years. "BTW, have you published pricing for Element 116 and 114?" Soon to be priced. The ELEMENT 116 will be announced shortly. It will be priced at $22k. This is mean to be the replacement of the VERITAS Monoblocks, although as you heard, a very significant upgrade. The ELEMENT 114 will be a stereo version to keep the price down and give those with space constraints what they want. The price will be announced Q4 of this year.
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Let me begin by saying I am by no means an "expert" on class D power amps, but here are my impressions. I first auditioned a class D amp around 10 years ago, driving a pair of larger, floor standing B&W speakers, and thought the result was somewhat harsh for acoustic music, but "exciting" for rock and roll. Fast forward to last Fall and I had the pleasure of auditioning a Mytek Brooklyn amp driving a pair of bookshelf sized KEFs and thought the result was very good! I also auditioned one of the PS Audio Stellar DAC/amp combinations and that also didn't have that harsh sound of the class D amps of yesteryear. In both cases, these amps sounded "fast" and "clean". One thing both owners said to me was that it took much longer than normal for these amps to break in and sound their best. If I were in the market for a new amplifier, I'd give class D some serious consideration. |
Cyrill Hammer (Souloution)The quote from Mr. Hammer is false. Here's why:"if you want to have your product performing at the cutting edge it is not possible with today’s known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz." As @merrilaudio states, the problem is dead time. Dead Time is the delay time that has to be inserted in the circuit so that both output devices are prevented from being partially on at the same time. If this isn't done, a phenomena called 'shoot through current' occurs. This causes the output devices to heat up and fail. The problem is that dead time causes distortion. So with any given output device, there is always a certain minimum distortion and associated maximum switching speed. Technics sort of got around the problem by brute force- going to an output device that was so much faster that they could reduce deadtime and also switch faster (BTW their 150 watt version of this is about $18,000....). However eliminating dead time is what works- you can actually have lower switching frequencies with lower distortion if you don't have to have deadtime circuits! As some of you may know, we've been working on a class D for a bit over a year and a half. Although we are known for tube gear, in particular OTLs and balanced tube preamps with direct coupled outputs, it turned out that we seemed to have something to bring to the class D table. May a year ago we had working concept, today we have prototypes that demonstrate how a class D sounds if deadtime is eliminated. Our amp is not based on anyone's modules and we have a patent filed with another on the way. So far the prototypes have switching speeds between 250KHz and 500KHz. The amp is very smooth and extended, lacking grain or harshness. It easily compares to many tube amplifiers in that regard. It is zero feedback and exhibits soft clipping. We don't think its ready for prime time yet; in that regard I've yet to hear a class D (including the Technics) that is, but we are very excited about our class D as it sounds better than any we've heard. I think merrilaudio knows what we are talking about; eliminating deadtime is the single most important hurdle to cross in class D amp design (especially if you can run MHz+ switching speeds), and I'm going to go on record that any amp that employs deadtime to work is an amp that will become obsolete. |
merrillaudio said... "The ELEMENT 116 will be announced shortly. It will be priced at $22k. This is mean to be the replacement of the VERITAS Monoblocks, although as you heard, a very significant upgrade." Hi Merrill. The new amps sound like they will be awesome...congratulations!!! Now... if I can only figure out where to come up with $22 K ..ouch ! Me thinks my Veritas monos will have to do. 8) |
“The TDAI-2170 is 100% digital, without sound-deteriorating digital-to-analog conversions. The digital signal drives the speakers directly, with no translation and no middleman.” @grannyring While this is the hype, the fact remains that all class D amplifiers employ an analog process. I think there is a lot of confusion about what is digital and what is switching, and also what must be analog. Here's a link that might help: https://www.hypex.nl/img/upload/doc/an_wp/WP_All_amps_are_analogue.pdf |
I'm going to go on record that any amp that employs deadtime to work is an amp that will become obsoleteBy definition, zero deadtime means that the devices must be both on and off at the same time, a physical impossibility given any reasonable technology. Zero dead time requires a series of perfect devices that remain invariant over temperature and time. A Class D amp with Zero dead time is likely an amp with a short lifespan. |
Hello @d2girls, your question does not have an absolute answer.... A lot has to do with bersonal preferences, because Merrill, Rowland, and Bel Canto all make some wonderful devices. Starting with Merrill... The Veritas monos were fabulous in their hayday.... Today they would still be worth a serios look... Although all things point to the new Merrill Oganessom series of Element 114, 116, and 118 being superior... Yep the Element 118 prototype that I had the fortune of having in my system for one week, while not well broken in and still evolving rapidly, was musically impressive to say the least! Rowland has 5 class D amps.... two I know well and I adore... THe M925 monos that I own, and the Continuum S2 integrated.... The following I know by their excellent reputation only.... the Daemon integrated just below $39K, the M535 bridgeable just below $6K, and the little entry level M125 at some $2.5K. Bel Canto has a number of amps.... THe Black series is their top of the line, while the Ref600 is more entry level. All the above are great products, I doubt that you’d go wrong with any of them.... And I have not heard of any reliability complaints about their class D output circuits.... But which brand or model might be Best is pretty impossible to say.... It depends on your budget for one thing, but most of all on your sound concept.... Assume that none of them are strident, all of them are pretty linear, all of them let you hear subtle harmonics, all of them yield deep and tuneful bass without sloppiness.... And yet, inevitably you will develop a personal preference for a brand, or for a particular model, or.... You might dislike the whole lot instead *Grins!* Why? ... "BECAUSE!" G.
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By definition, zero deadtime means that the devices must be both on and off at the same time, a physical impossibility given any reasonable technology.:) that is why we have a patent filed. Difficult takes a while- impossible is just a bit longer. A Class D amp with Zero dead time is likely an amp with a short lifespan.So far they run stone cold even when on for days on end. |
The problem is not dead time, or notch distortion. The problem is audibility and connecting that to any particular technical choice. What I mean is, all amplifiers, even all musical instruments, have "flaws." To some they may not be flaws, to some they may be "attributes." We can argue about them forever but the importance of any flaw has to do with it's audibility. We can talk about ways to mitigate "dead time" forever, but that does not make the issue audible. One thing that Revel and Bose both do incredibly well is to pay attention to technology not for it's own sake but for audibility and desirability. We could learn from these approaches. Best, E |
The quote from Mr. Hammer is false. Here’s why:And the rest seems like an ad. It’s not false as Ralph would have you believe. It is "also" a problem, but isn’t the "major problem", and the cause is of what many dislike what they hear in the upper/mids and highs which is a product of the switching noise and it’s associated filter. It is believed that the dead time will also be vastly improved with a 3mHz switching speeds. This analogy from Nelson Pass will help: "Imagine that the two transistors are runners in a relay race and that the signal is the baton they carry. In a real relay race, the runner receiving the baton begins running before the hand-off, which is made with the runners at speed. The runners who hand over the baton at a dead stop will operate at a severe disadvantage". (if that runner can stop on a dime from full speed, then take off like a nitro drag car, you have higher switching speed) And an interview with the great man (Nelson Pass) just a couple of months ago; JS:There has been an explosion in high-end Class D amps in recent years. Some companies now market some fairly sophisticated – and expensive – Class D models. Pass currently manufactures Class A and AB lines only. What are your thoughts on Class D? NP: Personally I think it’s a miracle that they work at all, but then I think that about my phone, too. I have great respect for people who can make Class D amplifiers sound pretty good, and for delivering low cost, high power, and efficiency. They have earned their place in the industry. That said, I am not tempted to go in that direction. Cheers George |
The problem is not dead time, or notch distortion. The problem is audibility and connecting that to any particular technical choice.Dead Time has nothing to do with notch distortion, but the chance exists that I mistook the gist of your comment. It’s not false as Ralph would have you believe.George, you've not thought this thru. You are correct that by increasing switching times you can decrease distortion. However, its not the filter that is an issue, in fact as the switching time goes up, there is a point where the inductance of the load is enough to eliminate the requirement for a filter! (Usually the filter fails to remove all the high frequency component. This component is known as the 'residual' and if the filter is designed properly, will be a sine wave of low amplitude. As such it will not interfere with other equipment and is far too high to be heard!) Now as you go higher with switching frequency, distortion goes down, but with any particular switching device- oh- I'm repeating myself; here's my comment that you apparently didn't read from above: The problem is that dead time causes distortion. So with any given output device, there is always a certain minimum distortion and associated maximum switching speed.Nelson's analogy is correct however, so imagine not having to wait for a transistor to shut off before the other one turns on! Now we can switch at much higher frequencies and with much less expensive parts. Alternatively, an amp with a lower switching frequency but no need for dead time can have distortion as low as an amp that needs the dead time and is switching considerably faster. |
It's simple G As it stands now the switching frequency noise output filter, has phase shift effects that reach right down to 5khz, that doubled for the worse at 10khz and doubled worse again 20khz. That's what many listeners find objectionable, in the upper mids and highs. If the switching frequency is moved much higher from the present 400-600khz to 2 or 3mHz, then the filter can be moved up accordingly. So it has no phase shift effects down to 5khz, but only then at over 20khz instead where it really doesn't matter. And the dead time will magically improve as well, it's a win win, for higher switching speeds that's why Technics with the SE-R1 persevered to get it, at a cost rrp $30k aud. Cheers George |
This has morphed into one of the more interesting and informative Class D threads I have witnessed. I wish I had something technical to contribute myself but I do not, however that is why i peruse these forums, to increase my own personal database of knowledge. But we do seem to have two diametrically opposed schools of thought of late, Switching Speed or Dead Time. Now just what is an outsider supposed to believe here? How do I choose which path is best to follow? Does one wait for the various technologies to duke it out and see which becomes victorious. Think VHS vs Betamax although maybe a poor analogy as the real winner did not win. It seems Class D is ready to come of age if you like but in what way, shape or form? Difficult choices ahead possibly |
Ah George, I was just trying to say that the three brands mentioned make some extraordinary products, but inevitably, there will be audio lovers who prefer the more lushous tone of classic tubes, or the starker tone of some SS.... And there is nothing wrong with that! But you are reverting instead to your single track paper-bound comments a priori of any live experience... I can only shake my grizling head *Rolls eyes!* G. |
But you are reverting instead to your single track paper-bound comments Only because of those "looking for confirmation" to what they think that Class-D is finally Hiend. It hasn't changed that much since it's inception, many you will find are buying Chinese modules some modded via Pascal EU, just more and more trying to make "big bucks" out of what is essentially very cheap to make, if you take away the "glitzy chassis" they have. NP: Personally I think it’s a miracle that they work at all. I am not tempted to go in that direction. Cheers George |
I have Bel Canto ref1000m in main system and C5i in second system. Both are fast and clean but sound different. Each is hard to fault and sounds perfectly lovely matched into the right system. I will probably never own anything other than Class D amps moving forward. If the C5i did not work out I was ready to move to a modest power tube amp in my second system moving forward but the need for that never developed. Both are absolutely wonderful pieces of technology and worth every cent. |
Here is an interesting read for those at odds with what’s being presented here. Not just with the filtering of the switching noise, which I primarily "bat" on about, but also what is a secondary problem of Class-D advantages in the "dead time". From the makers of the GAN transistors that Technics use in the SE-R1. " EPC’s enhancement-mode GaN (eGaN®) transistors switch up to ten times faster than silicon MOSFETs, with ‘zero’ stored charge. The increased switching speed of eGaN FETs allows amplifier designers to increase PWM switching frequencies, reduce dead-time, and drastically reduce feedback; producing a sound quality previously limited to large, complex, heavy Class-A amplifier systems." Also there could be a module for sale using these eGan transistors from Austin Texas. Elegant Audio Solutions of Austin, Texas, has produced an amplifier capable of a continuous power output of 200 Watts into an 8Ω, or 400 Watts into a 4Ω speaker load, with THD+N as low as 0.005% and very low feedback. Moreover, this is done without the need for a heat sink and eGaN-based amplifier can plug directly into the standard amplifier implementation of many existing systems. https://epc-co.com/epc/Portals/0/epc/blogs/elegant-audio-solutions-eGaNAMP2016.png Cheers George |
@uberwaltz i agree, the tech specs presented have been informative. For me, The random nature of personal testamonials and anecdotes have been just as important to expand my own breadth of knowledge. e.g., @mapman — the BC Ref 1000m’s (and per a prior post- many are happy with them Only with OLDER Thiels). And the C5I. And I will just add that the $500 Napa Acoustics Class A, B, and D all in one amp, the Cask series, made the KEF LS50s sing more naturally and organically that any other amp I have heard running through the LS50’s. And the Class D mode sounded the best IMO. And this was in a hotel room at this years NorCal CAS this year. https://www.napaacoustic.com/cask/ |
There are 3 ready made diy
EVAL BOARD
modules from EPC using the GAN transistors. Just add an smp, bung them in a box and away you go. http://epc-co.com/epc/Applications/ClassDAudio.aspx One the lowest power one available through Mouser for $1,388 usd each. https://www.digikey.com/products/en?%20WT.z_cid=sp_917_0110_buynow&site=us&lang=en&mpart... And the other higher power modules available "maybe"? through Elegant Audio Solutions of Austin Texas. http://epc-co.com/epc/Portals/0/epc/documents/thirdparty/EAS_eGaN_2.0-Channel_EvalKit-010116.pdf http://epc-co.com/epc/Portals/0/epc/documents/thirdparty/eGaNAMP2016_Consumer-123115.pdf Cheers George. |
Prove either is audible and unpleasant first. Then you might get me to care about either.Just like climate change? https://cdn1.vectorstock.com/i/1000x1000/05/10/ostrich-head-in-sand-vector-2090510.jpg Cheers George |
As my friend used to say "it all comes out in the wash"......meaning....it will be shown with time and experimentation which things do what as far as sound quality. We have George repeating over and over and over and over and over and over.....he he..... about phase shift due to filter effects....trouble is, he is guessing about its sonic effect. He knows nothing because he has not heard anything......he is just talking. He likes to repeat himself, repeat himself, repeat himself. But he has no actual information based on listening tests (the only thing real in audio). We have Merrill who has made an amp with low dead time and the amp will show us something about what he says. George will show us nothing about what he says. Hey, I think GANs, zero dead time and higher frequency switching (and lots of other things too) COULD make better sound. But only those who actually experiment and listen will know. We are at the beginning of a new stage in Class D. As these things get implemented by more companies it will show/prove what is really valuable. I believe that before long even the Merrill amps will be boat anchors. This game never ends. IcePower, Pascal, UCD (come on Bruno, let's see some GANs in your amps!), DAC, Nuprime (already switching at 700K), etc. will make amp modules with GANs, higher speed switching, etc......and these modules/amps will be very affordable. Viva La Revolution! I just talked to the IcePower distributor today and he is going to talk to the engineers at IcePower about what is being said here. All technology has a very short window of opportunity (as it keeps improving and changing). Merrill is riding the first wave of GAN madness. I bet there are many more waves coming. This ride is fun! We have a lot to look forward to......better sound, smaller amps, less power consumption and less cost. A win for everyone. |
Seems to be very easy on this forum to attract attention for theories that have nothing to do with what you have heard much less owned and it is the same posters over and over in thread after thread. When you have an opinion of a technology much less a product tell us when you actually heard it and under what circumstances. It is pretty obvious that these members have never owned the products in question. If so tell us what they were. |
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We have George repeating over and over and over and over and over and over.....he he..... about phase shift due to filter effects....trouble is, he is guessing about its sonic effect. He knows nothing because he has not heard anything......he is just talking. Ok, were stooping down to that level. Many of us know your comments are biased and maybe in it for the monitory gain, and you’ll say anything because of this, and your protection of it. http://tweakaudio.com/EVS-2/EVS_1200_amplifier.html I have no financial interest in Class-D at all, just what I hear and others report.. |
erik_squiresProve either is audible and unpleasant first. As others have have stated, explained, and explored no one hear owes you any proof, documentation, or substantiation of anything hear at all if you seek reliable, testable, repeatable, proof you are of course welcome to collect, formulate, and collate you're own but to insist, demand, and compel others to do your work hear for your sole benefit is I believe what is in English called "presumptuous." |
erik_squires"The problem is audibility and connecting that to any particular technical choice" When audiophiles, engineers, and expert listeners report results that are substantially similar with a given design, topology, or methodology it is a pretty safe observation, deduction, and conclusion that the design, topology, or methodology is responsible for the outcome and result regarding performance. |
Yep, vaccinations cause autism, soy causes infertility and androgeny, the moon landing is a hoax, the Earth is flat, and... Class D is digital and invariably sounds terrible. No end to ever-popular conspiracy theories and urban legend, Ain’t it? But wait, has anyone seen where I mislaid my trusty high-end tinfoil hat? Aliens are after me again *Grins!* G. |
As it stands now the switching frequency noise output filter, has phase shift effects that reach right down to 5khz, that doubled for the worse at 10khz and doubled worse again 20khz. That's what many listeners find objectionable, in the upper mids and highs.This statement is false. The filter is set to be operational at a fairly high frequency, and are usually 12 db per octave filters. 6 db/octave filters exhibit phase shift over the widest range, so if the pole frequency is at 90KHz you could see some artifact at 9KHz but not at 5KHz. But most filters I've seen are 12db/octave and so don't have phase shift artifact anywhere within the audio passband. What many listeners likely 'find objectionable' is not the filter- its likely something else. Several issues exist that can account for that- higher ordered harmonics caused by poor loop feedback implementation, breakdown of the encoding scheme at higher volume levels, distortion from the input circuit... but its not the filter. IME a good class D amp has artifacts, but not the kind typical to traditional solid state, so in many cases I find especially the later generations to be more musical than traditional solid state. |
Unfortunately, this book is now out of print, but I think it would remind us of where we are : https://amzn.to/2M0bBLB |
@lukaske @toetapaudio Note the VERITAS Monoblocks from Merrill Audio used the Hypex NC1200 module for years. It was tested by many audiophiles and societies against other implementations and was found to still be the best. We now have a new proprietary Class D design from Merrill Audio on the Oganesson Line of amps. These are an order of magnitude better then the VERITAS or anything else in that group. What makes the difference in the use of GaN transistors. Tthe MOSFETS in the prior Class D designs, including the Hypex simply cannot do what the GaN transistors can. Other Class D designs, including the Hypex NC1200 utilize heavy feedback which tend to have loss of detail and become sluggy. Now imagine no feedback loops. That brings a new sense of ease and air to the music, along with a strong, fast attack, yet no overhang or edge. Soon the discussion will shift to who has the best Class D versus is Class D good. We believe we are leading the way on that. |
I am in agreement with Erik. I have a Class D integrated hybrid amp and if it suffers from switching distortion or dead time, I sure as hell can't hear it. Granted, I haven't been able to compare it to dozens of other amps, class D, AB, A, or otherwise. But what I have had in the past which was a McIntosh C-45 preamp and MC-402 poweramp. It took less than 5 minutes out of the box (new Class D) cold and not broken in yet, to tell it was vastly superior to the Mac gear. It has what a lot of you considered outdated Hypex 400 modules and to my ears still sounds wonderful. I have been exposed to the expensive exotic stuff over the years and don't feel I'm missing much in resolution, dynamics, smoothness, musicality or whatever. There are several of you that seem to think Class D is almost unlistenable, probably in not so many words. Why so many of you have to make such a big deal about it is beyond me. What many of you will realize is class D is the future of audio amplification. I believe that is inevitable. IMO. |
These guys are leading, advancing future of Class-D with their GaN semiconductors. There’s much to choose from on the EPC GaN Class-D website. After having a good look at everything this one is the pick I think, it’s got everything, programmable DSP and the kitchen sink. digital inputs, analog inputs, usb. Just hook up +-32v and away you go. 8ohm 200w supposed to double into 4ohm 400w?? that’s like saying perpetual motion is real, https://youtu.be/4b8ZsFszE8I?t=2 be nice to see what it can do into 2ohms. http://epc-co.com/epc/Portals/0/epc/documents/thirdparty/EAS_eGaN_2.0-Channel_EvalKit-010116.pdf Cheers George
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What many of you will realize is class D is the future of audio amplification. I believe that is inevitable. IMO.It already is, but that's because most consumers don't care about audio quality and manufacturers are constantly looking for ways to skimp on production costs. The benefit to the consumer is saving a few $$ on their electric bill. The benefit to the manufacturer is lower production and shipping costs. As BP clearly states, sound quality is not the intended benefit: S&V: Generally speaking, what are the key benefits of Class D versus the traditional Class AB and Class A designs that have long been favored by audiophiles? Which approach is best: modding a Prius to be almost as quick as a Lambo (with better MPG), and charging Lambo prices, or just starting from the ground up with a real gas-guzzling Lambo? Personally, I'd take the latter though I can understand the argument for the former. |
Which approach is best: modding a Prius to be almost as quick as a Lambo (with better MPG), and charging Lambo prices, or just starting from the ground up with a real gas-guzzling Lambo?+1 That's about it alright, for now anyway. I think we maybe in for a shock in the not too distant future, re all the stuff EPC is doing with the GaN. Then all the Class-D's being raved about at present, will become as popular as solid state was when they were made with Germanium transistors when Silicon transistors hit the market. You couldn't sell them to save yourself, they made excellent door stops and that was it. Cheers George |
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I do respect everybody else experience and I believe it's system dependent. I can see a very front image Persona or similar as a great match for Class D. Being a recent and proud owner of SF Memento, which I like better than the one in above and few others including recent SF as well, I had to look for a replacement for my beloved Karan Acoustics integrated amp in the need for more power at lower impedance. My local dealer kindly let me test at home and at his place Luxman 900, 700, 590, Krell and AR ( I skipped Mc all together and $oulution) and then Bel Canto m600 and Black. To my not so young anymore ears Bel Canto Class D do sound very good and again might work very well with many systems. Musically speaking ... well I am very happy were I landed with a 625s2... |
My speaker system is DIY, assembled from various sources: Bullet tweeters + 300 Hz conical-horns with field-coil modified B&C DCM50 compression drivers + (2) 15" Acoustic Elements DiPole 15" woofers in (2) U-frame cabinets per side. Each driver is powered by a modified/upgraded NuForce Ref 9V3 amp. The midrange horns are driven by Ref 9 monoblocks, the other drivers are powered by 6 channels of a 7-channel NuForce HT amp, with the same modules as the mono amps (also modified/upgraded). If I switched to eight Class A or Class A/B amps - either tube or solid state - the listening room would be far too hot and my electric bills would go through the roof. Class D is the only practical way to go for me. I am not wealthy. My stereo can go toe-to-toe with any system out there. Like any ultra-accurate system it is brutally revealing of bad source material. But great recordings shine like the sun. |
