Hello atmosphere,
Please don't treat my occasional post questions directed to you, and your vast amp design knowledge and experience, as anything even remotely close to an attempt at rushing your class D amp design and development efforts. Of course, I understand you're going to take whatever time you deem necessary at every progression in the nuts and bolts process of creating a high quality class D amp that bears your company's well respected name.
My layman aim remains the same, which is just to seek out and utilize high quality system components that maximizes my music and HT listening experiences. Having subject matter experts, such as yourself, explain things to me in an easily understood, relatable manner while educating my posterior along the way just happens to be a much appreciated bonus. Thank you.
For example, your concern about excessive damping factors on class D amps is something I can relate to due to experiencing its effects on my system's performance. I've previously driven a pair of Magnepan 2.7QR speakers in my system with three different brands/models of high powered and high damping factor class D amps, two stereo units and a pair of mono-blocks. It was immediately very apparent to me with all three that the bass response was more prominent than with any of the numerous non-class D amps I'd previously used on these same speakers.
At the time, I considered this very powerful, taut, dynamic and prominent bass response the best I'd ever experienced on the 2.7QRs, that are 3-ways with a rather large 623 square inch dipole planar-magnetic bass panel section on each speaker. However, I subsequently purchased an Audio Kinesis Debra 4-sub distributed bass array system with all four subs powered by a 1K watt class AB amp/control unit. I continued to drive the 2.7QRs full-range (down to their rated bass extension of 35 Hz +/- 3db) with the class D amps and the 4-sub bass system was restricted to reproducing only the bass content from 20-40 Hz.
The bass with this setup was definitely improved in power, detail, dynamics and especially realism and naturalness. Over time and in retrospect, I slowly became aware that while I really enjoyed the bass response solely reproduced by the class D amps and the 2.7QRs, the bass sounded much better with the AK Debra system included. My theory is that the very high damping factors unique to class D amps was truncating the decay times of the bass notes. The four Debra subs, being powered by a class AB amp that has a lower damping factor and did not shorten the decay times of bass notes, therefore allowing the bass to sound more realistic, detailed and natural. Does this make sense to you?
Thanks,
Tim
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Have you made a decision yet on whether you’ll be offering free limited in-home trial periods for auditioning? We're not nearly that far along! With regards to GaN performance, they can be variable depending on who made them and their intended application. Many of them have a reverse diode conduction phase which can really throw the designer for a loop. While they are faster, MOSFETs have been steadily getting faster too so at practica switching speeds we're seeing now in another year or two MOSFETs will probably work just as well. One problem we're seeing is its very easy to build a class D with a very high damping factor, much higher than any speaker should really see. |
Hello atmasphere,
Thank you for your very good update on your class D amp development. Very interesting, although not very surprising, that you decided to utilize GaN FETs in your design given their ultra fast switching on/off capacity which enables the elimination of dead-time and lowers distortion. I’m not sure if you discovered yet what Merrill, of Merrill Audio, stated that he has discovered: that the newer GaN transistors don’t perform as well as some of the older examples.
I remain very interested in listening to your new class D amps in my system. I recently upgraded my system with a pre-owned Levinson 326S preamp and Magnepan 3.7i speakers. I’m currently using a pair of D-Sonic M3-600-M mono-block class D amps rated at 1,200 watts @ 4 ohms that are performing very well driving the 3.7is.
I understand the 3.7is likely don’t require 1,200 watts to perform optimally but I believe they benefit from a ready and steady availability of high current. My issue is that I’m uncertain if 200 watts @ 4 ohms would be sufficient for them. I’m also uncertain whether there would be a net overall sound quality gain in my system by utilizing very well designed class D amps, with reduced dead-time and distortion, but perhaps less than optimum current availability. I’ll likely only find out for certain by auditioning them in my system.
Have you made a decision yet on whether you’ll be offering free limited in-home trial periods for auditioning?
Thanks,
Tim
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We're still working with prototypes. They have had 100 watts and double power into 4 ohms. Since last spring, they have had GaNFET output sections. We compare them directly against our tube OTLs as a reference. Mostly we've been sorting out layout issues; designing a class D from scratch using individual parts is challenging if you want high switching speeds! But we've been sorting things out, sometimes one at a time as problems are identified and solved.
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atmasphere,
Thanks for the very good info on amp feedback.
On a totally different subject, I just bought a pair of pre-owned Magnepan 3.7i speakers to replace my current almost 25 year old 2.7QR panels. I'm thinking my Levinson 326S preamp (very quiet, neutral, detailed while portraying a very good soundstage) and pair of D-Sonic M3-600-M class D monos (1,200 watts into 4 ohms) will be a good match with the 3.7i but I won't know for sure until they're installed tomorrow and can begin listening.
I'm just going to listen, evaluate and hopefully enjoy this combination for a few months. I have high expectations but, as we all know, the proof's in the sound quality and our subjective opinion.
If I don't thoroughly enjoy the results, I'll probably be in the market for a new pair of fully balanced monos, preferably class D. I'd love to audition your new class D amps if I'm in the market, before I purchase anything else and if they'll be available for audition and possible purchase in the next 3-6 month timeframe. I understand if you're currently reluctant to share any definitive information but would appreciate any info you're comfortable sharing at this point. I'm very curious and interested in listening to your efforts.
Thanks,
Tim
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Would you say there is inherent limitation in the phase shift that is a
factor of the comparator speed, digital logic delays, and turn-off time
of the FET? What do you think a practical limit is on that? That may put
a practical limit of a few-10 degrees at 20Khz, but that would be
inaudible. The phase shift is indirectly related to the speed of parts like the comparitor (which typically has plenty of more speed than the output section). It is directly related to the filter at the output. As I understand it from you and Bruno Putzeys as a layman, there is
no such thing as too much feedback with class D amplification. The
generally accepted concept that feedback negatively effects the sound
quality of traditional linear amplifiers may be true, but this aversion
to feedback doesn't apply to class D amplifier design. Very high levels
of feedback, in an intelligently designed class D amp, are actually
utilized to optimize the sound quality throughout the entire audible
frequency spectrum.
Am I understanding this correctly?
That's it in a nutshell. The problem is phase shift in traditional designs prevents the application of the required amount of feedback in such amps; otherwise oscillation will occur. For this reason **every tube and solid state amplifier made has had insufficient feedback**. This has resulted in the applied feedback adding its own distortion- which is interpreted by the ear as brightness and harshness. This is why every amplifier with feedback up until now has sounded brighter and harsher than real life, and has fueled the tubes vs transistor debate all these decades. The industry has also been complicit in this problem, so when you see harmonic distortion measurements the fundamental frequency is usually fairly low (60Hz is common) so as to not get in trouble with the gain bandwidth product limitations of the amp under measurement! And this also explains why zero feedback amplifiers (like our OTLs) exist, as by designing a circuit that is linear enough to run without feedback the harshness and brightness of feedback is avoided. Transient Intermodulation Distortion is a symptom of poor feedback loop design coupled with poor gain bandwidth product and insufficient feedback. Can you define the time domain characteristics of feedback in a Class-D amp and linear amp? Yes. In a class D amp its all about propagation delay. In a conventional amplifier its all about phase shift as capacitive strays roll off the response (introducing phase shift). Effectively both have the same effect- at some high frequency the feedback is no longer negative so oscillation can occur. But unlike a conventional design, in a class D you can take advantage of that oscillation by using it as the switching frequency. |
The proof will be in the pudding, as there are Class-D’s coming out with little or no feedback, Merrill Elements being just one with it’s said to be a very good sound. From EE Online "If none of these issues are addressed, it is difficult to achieve PSRR better than 10 dB, or total harmonic distortion (THD) better than 0.1 percent. The standard solution for compensate for the poor performance of a Class-D system is to add negative feedback, but a large amount of negative feedback increases Transient Intermodulation Distortion (TIMD)." Question is does Putzey’s designs with large amounts of feedback, ever state TIMD "Transient Intermodulation Distortion" I think not only ever seen THD specified https://pdfs.semanticscholar.org/b3c0/a892a982ebde91f83f228905dac30186f827.pdf Cheers George |
This can also be said about linear amps, but they sound crap when done.
The goal is to have the best engineered design with the lowest
distortions without negative feedback, and then if it can be done just a
little local feedback around the input/driver stage to clean things up,
but no global feedback compassing the output stage as well. This is but one design methodology, and to say unequivocally it is the best is ... a leap not shared by all. It is more religion than science. Can you define the time domain characteristics of feedback in a Class-D amp and linear amp? |
Very high levels of feedback, in an intelligently designed class D amp, are actually utilized to optimize the sound quality throughout the entire audible frequency spectrum. This can also be said about linear amps, but they sound crap when done. The goal is to have the best engineered design with the lowest distortions without negative feedback, and then if it can be done just a little local feedback around the input/driver stage to clean things up, but no global feedback compassing the output stage as well. It was Matti Otala back in 1970-80’s that was the guy behind it all in solid state amps, and is still used today by the very best, but hard to design for. Look for today's amps that say in their description/specs "no global negative feedback" Cheers George |
Hello atmasphere,
As I understand it from you and Bruno Putzeys as a layman, there is no such thing as too much feedback with class D amplification. The generally accepted concept that feedback negatively effects the sound quality of traditional linear amplifiers may be true, but this aversion to feedback doesn't apply to class D amplifier design. Very high levels of feedback, in an intelligently designed class D amp, are actually utilized to optimize the sound quality throughout the entire audible frequency spectrum.
Am I understanding this correctly?
Thanks,
Tim
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atmasphere,
Would you say there is inherent limitation in the phase shift that is a factor of the comparator speed, digital logic delays, and turn-off time of the FET? What do you think a practical limit is on that? That may put a practical limit of a few-10 degrees at 20Khz, but that would be inaudible.
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I did not understand what kind of patent is this as class D amps are widely used for already more than a decade. 2 decades actually, but that does not mean that everything to be known about them is already known. The proof’s in the pudding when we see independent measured specs on.
what switching frequency used
output filter corner frequency
switching frequency residue on output
dead time performace
phase shift figures from 2khz to 20khz
rms output wattage just before clipping into 8ohm, 4ohm and 2ohm.
All of which are known Achilles Heel’s of class-d
This type of generalization is problematic! A self-oscillating class D amp can have a fairly low switching frequency (400KHz for example) and consequential low filter frequency (80KHz) and yet little or no phase shift at audio frequencies. This is because a self-oscillating class D amp can run so much feedback that it can correct phase shift and even distortion caused by the application of loop negative feedback. In order to do this the feedback has to be in excess of 35dB which is nearly impossible with conventional amplification due to poor gain bandwidth product. But gain is easy to create in class D circuits. |
comfortably driving 1000W into 4Ω and up to 2000W into 2Ω That’s way too vague. Just like Merrill quotes. Ask him this, it should be done by independent bench testing, but he should tell the truth. In stereo what is the RMS wattage "both channels driven just before clipping"into 4ohms @ 1khz In stereo what is the RMS wattage "both channels driven just before clipping"into 2ohms @1khz See if you get a straight answer, not even Merrill would give an answer to this and I asked 2 or 3 times on the Element 118’s (true monoblocks not bridged stereos) their was a dead silence with this like he never seen the posts, even though he happily answered many others I asked, and his amps are in a higher league than these I believe. Cheers George |
Measurements of Tommy's old amps are online. No issues into 2 Ohm except a hit of hit on frequency response. |
@georgehifi, Tommy's MEGAschino MK2 specs into 2 Ohms;
MEGAschino channel boards are capable of comfortably driving 1000W into 4Ω and up to 2000W into 2Ω
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GaN based Class-D in that they are going for bench specs as opposed to sonic excellence. I worry when a manufacturer says this, (trust me it sound better) We are able to achieve better bench specs than any other Class-D we’ve seen Then further down he says this????? (hang on he just said spec don’t matter) The proof’s in the pudding when we see independent measured specs on. what switching frequency used output filter corner frequency switching frequency residue on output dead time performace phase shift figures from 2khz to 20khz rms output wattage just before clipping into 8ohm, 4ohm and 2ohm. All of which are known Achilles Heel’s of class-d Cheers George |
George,
I cannot affirm anything certain on this, but, perhaps, there is a doctor that already can already convince the girl not to smoke, chain smoker is no more needed. The girl then would shine with her legs and face.
According to Tommy O from Digital Audio Company, their module design is already fast enough so that there is no further need in GaN-based technology (used, e.g., in Technics SE R1). I am citing what he wrote to me in this regard (please note that i am unable to judge on the technical part/proof for his statements):
citing :
" I wanted to mention this before…. These GaN based Class-D amps have the same issue as other non-Cherry Class-D in that they are going for bench specs as opposed to sonic excellence. Without getting too into the technical aspects, GaN FETs require use of support chips that don’t support our unique topology, and our design is different in that it’s already super fast (the benefit of GaN is supposed to be speed). We are able to achieve better bench specs than any other Class-D we’ve seen, but we “tune” the modulation and control for best sound, and this costs a few dB here and there -- but sounds better. For example, the MEGA design can reach about 130dB and 0.0004% THD on the bench before tweaking for sonics. This is with non-GaN FETs. After tweaking, the specs are still great (120dB and 0.001% THD), but the smoothness is preserved, and the harsh/analytic sound of other amplifiers is not anything we want coming out of a Cherry Amp!! We are always getting compliments on sound quality, and this is the “proof in the pudding”. "
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Could we combine pretty face with nice legs without chain smoker in class D?
Not yet affordable, one day maybe, or now if you can afford the Technics SE-R1, it addressed all of the ugly's of Class-D dead time (big girl) and switching frequency (chain smoker). Cheers George |
Could we combine pretty face with nice legs without chain smoker
in class D?
My speakers (Thiel CS 6) go down to 2.5 ohms at 8 kHz, the output impedance of Megaschino is measured at 10
kHz. I did not note any damping problem though am a bit surprised with the power issue.
Supposedly it gives over 600 watts at 4 ohms, that i do not really perceived (I feel it gives about half of that, though its power is quite sufficient for my needs).
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In a Class D amp this would only describe how loud it plays at 2 ohms without sonic impact not much else. Damping factor at the frequencies where impedance drops is far more important. Still nothing on how it handles 2ohm loading and if it’s got good current drive down that low (increasing it’s wattage a lot from 4ohms) |
Class d is the big girl with the pretty face, or the chain smoker with nice legs. |
Let me note that MEGAschino is not a typical representative of class D: it is quite heavy (about 20 kilos) Because it has a linear power supply using a massive toroidal transformer, which to me is a good thing, never been keen on noisy switch-modes no matter how well built. Patented and proprietary circuitry designed in-house. Could be good, no off the shelf stuff like many others use. Still nothing on how it handles 2ohm loading and if it’s got good current drive down that low (increasing it’s wattage a lot from 4ohms) https://www.cherryamp.com/dac-home Cheers George |
I did not understand what kind of patent is this as class D amps are widely used for already more than a decade.
Meanwhile, I have some class D updates and can share my first (still superficial) impressions on a class D Cherry MEGAschino amp (a demo stereo version). I got it recently from Tommy O from DAC (Digital Audio Company) together with a (demo) DAC SHV 2 with volume control.
Let me note that MEGAschino is not a typical representative of class D: it is quite heavy (about 20 kilos), not as small, it does get hot (not extremely hot) and costs a few times more than an average class D amp. So nice characteristics of a class D amp are not present in this amp, which is based on a module designed by the same company (DAC). At the same time, it gives a detailed, clear non-wax and non-frozen music reproduction. I can even say that the sound quality is more alive and detailed than that of may class AB amps, a surprise for me. Roughly, it sounds like a good solid state class A amp while gets less hot and is still less heavy. Again, these are my first impressions that might be completed or/and altered later.
At the same time, i am not impressed with DAC SHV 2 (about $1500 new). It has a single digital input. As a (passive) preamplifier, it was not so efficient with MEGA -- the sound had no dynamics. As a DAC, it is slightly better than PS Audio Gain Cell (slightly more soundstage and definition), but Gain Cell costs the same and is also a real preamplifier (with enough number of digital inputs, several line inputs, coaxial, optical, USB etc).
Currently I use $650 Nuprime HPA 9 headphone amp with MEGA as a preamplifier, with very positive results (although HPA 9 is class A). My desire to stay in class D is not (yet) fulfilled.
Though in terms of ratio performance/price MEGAschino may not beat other class D amps, in absolute terms, it is a very good sounding amplifier. I hope I will stay with it in my main system.
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Class D stands for drier than a desert. |
If I may just a thought to keep in mind. The newer Low Mass amps give remarkable performance, but as with all things sometimes (most of the time) changes require system changes as a whole. Converting from higher mass to lower is a big change. For one thing a growth in soundstage that can easily double and more, when system setup is done correctly. enjoy Michael |
Stringreen rightfully so but my point is that Class D amps are fast efficient with less parts. But let me make it clear I'm not completely ready to give up my Conrad Johnson amp and I will use your words, not yet. I will use Class D amps because I like what they bring to the table so I will use both. If I get bored with one I will insert the other.
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Class D amps are going sound different then Class A or Class AB amps but in a good way. I think they should be judged on their own merits and naturally we will always make them comparisons as we should. It is much like going from gasoline driven cars to electric. With the point in mind that the fastest car on the planet is an electric car.
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Dang, that Mola Mola listing by Willgolf would be a nice catch by someone that can afford it. The benefits of depreciation but with something unused.
I am really enjoying my first foray into Class D. I swapped out the fuse for an SR Orange and added a Wireworld Electra power cable. Even Spotify sounds surprisingly great (to me).
With no music playing, my speakers are dead quiet, no ocean noise. The only thing I am missing from my previous class A is the heat it would be pumping into my living room during these frosty Southern Cal Winter evenings.
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Sorry @hm1 (Howard Milstein) but not a single negative comments in any of your reviews that I read. They all appear to be written as advertisements. Here's a good example of what I mean (W4S mINT review):
Out of curiosity, I decided to laboriously drag out my almost 40-year-old vintage Spendor BC3, loudspeakers (known to have a pretty horrendous impedance curve as many of the finest amps sound quite unhappy trying to drive it). To my surprise, the Mint made this speaker ‘sing’ like I had not heard in many years! Horrendous impedance? Since when is 8 ohms and SPL of 105 dBA Horrendous? ANY Class-D amp should have no sweat driving these speakers.
Specifications: Type.................................four-way, floorstanding loudspeaker L.F unit............................Spendor 12 inch (plastic cone) M.F unit...........................Spendor 8 inch (1.5 inch voice coil, plactic coil) H.F unit...........................Celestion Type HF 1300 and type HF 2000 Crossover points.............700Hz to 3kHz to 13kHz Impedance......................8 ohm Frequency range............30Hz to 20kHz Frequency response......+/- 2.5dB, 50Hz to 14kHz Power rating...................70 Watts Sensitivity..................... +2.5dB relative to 1dyne/cm square/volts applied Sound pressure level.....105 dBA Connection...................."XLR" 4pin Weight............................75lbs
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Noble100....see my new listing on Mola Mola Kaluga and Makua.
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Hello niodari,
Sorry, I forgot you're in Mexico. I'll be down in a couple days and I'll bring the amps. Don't worry, my wife and I will be out of your place by Spring. Winters are a bit cold up here.
Looking forward to your impressions. I've been reading about the Cherry Megaschino and it seems like a good one.
Best wishes,
Tim
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@matias do you know how MEGAschino compares with your class D Apollon NC800SL? No idea, I am curious about them too. |
Thanks Tim
I do not plan to be close by in near future but will bear your proposal in mind. If you will visit Mexico i would suggest you the same.
As i told you, i will let you know about my impressions on Cherry Megaschino and Cherry DAC with volume control once i will have them. Earlier i have ordered a more moderate Cherry DAC 1 tb which gives a pleasant tube -like sound. I have bough a demo one for about 400$ and it sounds not much worse than $7000 reymio dap 777 thought it has a single input, as one i have ordered recently.
I remain curious to audition your d sonic monoblocks.
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Hello niodari,
Yes, my goal is to stay in class D, too. I've tried to keep up with class D developments for years now and I've been thrilled with the performance of all the D amps I've purchased thus far. The downside of this is I'm constantly learning about class D amps that get very good reviews and I'm always curious and want to give them a try in my system, which can get expensive.
My current plan is a good example. My system is performing very well right now and my D-Sonic M3-600-M mono-blocks are excellent for both music and HT. My Parasound Halo P-6 sounds very good but I'd like a smaller preamp, perhaps a class D with a smaller remote and a more precise volume control. I really have no good reason for buying new class D mono-blocks other than very good reviews on the Mola Mola Kalugas and the Merrill Veritas along with a curiosity about how they'd perform in my system.
I'm currently planning on buying the Mola Mola Makua preamp and Kaluga amps in the next 30 days or so but I'll also look at the Megaschino and Cherry dac if it can also serve as a single balanced xlr input preamp.
When the new equipment arrives, I'd definitely be willing to sell my D-Sonic amps to you if you'd like to buy them. They're both in flawless operational and cosmetic condition. I believe I still have their original packaging and manual. They were $2,100 new and would probably be asking $900 for the pair with their pair of isolation platforms available for purchase for an additional$100. My system details have some photos of both and, if you live close enough to Noblesville, Indiana, you're welcome to stop by and check them out in person if you'd like.
Thanks,
Tim
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Hey Tim,
Good intentions, I wish you to come to a correct choice (by the way,
it would be interesting to try your D-sonic momoblocks
in case you wish to sell them).
My journey to class D is not yet so extensive, in fact it it remains at an initial step - a light journey to Class D via class A, a non-expensive experiment that i made I have tried to replace PS Audio Gain Cell ($1700) pre/DAC with a Nuprime PHA-9 ($650)
as a pre for PS Audio power Stellar S300, with a quite positive result. The Nuprime has surpassed my expectations
(also taking into account its price): instead of a wax clinic sound
now Stellar gives a live open well balanced sound that
is already pleasing for audition - an essential difference for me, from non-pleasing to a pleasing sound. HPA-9 is class A, it gets hot and the hotter it gets the better it sounds - no way, this is how class A works. Supposedly, it is designed to give a tube-like sound, which, i think, is achieved. It turns our that the cosmetics may change the face -- something that i did not expect. Perhaps, some tube pre would even do better, but i am not currently interested in this, as a good value Nuprime has already emerged. I feel now safer and becoming convinced that class D may attain what i wish.
My goal though is to stay in class D -- not yet clear if it is possible. We need to find a class D pre that does the job correctly, without any cosmetics, and then see if a power class D amp will give a desired result.
To this end, I soon expect to receive a Cherry MEGAschino class D power amp and a Cherry DAC with a volume control. It is a demo
MEGAschino (DAC is also demo) unit sold for $3900, $2200 below its retail price. You may wish to hold on, I will let you know about my impressions on Cherry amp in a near future.
According to what i read,
MEGAschino is comparable with the best class A amps (@matias do you know how
MEGAschino compares with your class D Apollon NC800SL?). I feel it should be close to the reality, i will keep you posted.
Cheers
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I went from a Parasound A21 to Class D, no difference in sound.
Something seriously wrong there. |
I went from a Parasound A21 to Class D, no difference in sound.
With no difference in sound, the Class D was a better amp. Cheaper, cooler, less expensive to run.
The Luxman I replaced it with beat them both, at 6x the price.
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Class D world economic stimulus packages. Plus we don't lose our socks as much when we sell them on the used market. |
What is it with Class-D owners, my last loved amp lasted more than 8 years, sources usually 4-5 years.
But Class-D owners seem to be in a hurry to get somewhere by changing their Class-D's like like they are a pair of socks or jocks.
Cheers George |
Having owned 3 class AB integrateds before, I have started my class D journey with a pair of Calyx Femti power amplifiers, which I still have on a 2nd system. They are based on an ICEpower 125ASX2 module. Having liked them, my 2nd amp was a Wyred 4 Sound STI-500v2, also based on a pair of 125ASX2, no coincidence.
Then I decided to upgrade to separates and tried in my system a friend's Nord NC500 with the Rev C Sparkos small opamps. I liked what I heard and decided to keep Wyred 4 Sound as a preamp (bought the excellent STP-SE stage 2) and chose my 3rd class D amplifier to be an Apollon NC800SL, also based on a pair of Hypex NC500 modules, but with the larger Sparkos opamps. This current pair of separates cost me about 4.5k usd (preamp was 2nd hand), which is a steal. This pair is a giant killer and I think it would be very, very difficult to beat without spending some big money (tens of thousands).
The STI-500v2 integrated went to my brother's system by the way, so all class D amps are still in the family. :) |
Hello niodari,
In retrospect, I’ve been so impressed with class D amps in general that I’ve consistently upgraded to better performing examples over the past 7 years or so. I began my class D journey with what I consider the budget king of D amps, the Class D Audio SDS-440-CS stereo amp, that was a good quality example at the exceptionally low bargain price of $630 at that time.
Mainly out of curiosity a year later, I bought an even more competent class D stereo amp, the Emerald Physics EP-101.2-SE, on sale at the time for about $1,000 and a noticeably superior performer.
About another year later after reading numerous very good reviews, I bought my 1st pair of mono-block class D amps, the D-Sonic M3-600-M for $2,100/pair that were and are the best performing amps I’ve ever driven my main Magnepan 2.7QR speakers with by a large margin. I’m still utilizing these as my main speaker amps about 5 years later in my combo 2-ch music and HT system. My 2 stereo class D amps I purchased have been used in my system as surround sound channel amps with very good results and are still going strong.
So, I’ve been climbing the class D upgrade ladder for the past 7 years and enjoying the entire slow ascent continually along the journey. I’ve progressed from good performance rung to the better rung and I’m currently on the very good class D performance rung of the ladder. Now, I have a keen urge and curiosity about the prospects for my overall system performance quality if I climb another rung higher and purchase one of the best class D amplification examples currently available.
I currently believe the current top rung of the class D ladder probably equates to the newly released Merrill Audio Element 118 monoblock amps or the Technics model which both utilize the GaN extremely fast switching transistors. Interestingly, I was talking to Merrill of Merrill audio recently and he stated he’s discovered the older GaN transistors sound better than the newest ones.
However, being now retired and on a reduced fixed income, buying a pair for of either for about $36K/pair for them would likely entail me being required to dine on cans of cat food for my remaining years. As attractive as that sounds, I’ve decided to instead settle for the penultimate rung on the class D upgrade ladder by eating tastier meals and purchasing one of the following 2 preamp and amp upgrades for my system soon:
Option#1. For a total of about $10K, buying a pre-owned Levinson 326S preamp and a pair of Merrill Veritas mono-blocks. Merrill also told me he’s getting numerous pairs of Veritas back as trade-ins that he’s doing complete inspections on and reselling for about $5K/pair.
My requirements for a preamp are at least two balanced xlr inputs, at least one balanced xlr output, a convenient HT passthru capability, a precision volume control with 1db or less adjustments, under about $8K used and a good remote.
Option#2. For a total of about $12-$14K, buying a pre-owned Mola Mola "Suite" consisting of a Makua preamp and a pair of Kaluga mono-blocks.
Both of these options are about 50% less than new and I’m currently in the middle of my search for units in very good condition and with a current preference for option#2. Unfortunately, I’m unable to audition either option in my system but I’m looking for dealers or individuals, within about a 100 mile radius of Indianapolis, who may have any of this gear available for demo and purchase.
My goal is to purchase within the next month. I’ll also have a Parasound Halo P6 preamp w/remote and a pair of D-Sonic M3-600-M mono-blocks, both in very good condition, available soon for purchase at very reasonable prices if anyone’s interested.
Tim
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Jeff Rowland is an excellent class D ICE POWER amp. Nice option. Very nice.
Try to listen, just it.
Just it. Just listen. |
noble100,
Thanks for your detailed, informative reply. Much appreciated. |
Best class D i can think of is without a doubt Bel Canto Black ACI 600.Most likely the best single chassis class D integrated amp out there, probably better than more expensive separates.
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Hello turnbowm,
While it is true that class D amps in general emit radio frequency (RF) energy that can interfere with AM/FM frequency reception, class D amp designers are very well aware of this issue and typically make containing, controlling and attenuating these RF emissions a top priority in their designs.
If all class D amps were to be tested and ranked by RF emissions, however, I suspect the results would vary significantly between amps and that they'd also likely be directly related to the skill level of each amp's designer and the new retail price of each amp.
OTOH, I've purchased and used many stereo and monoblock class D amps in my system ranging in price between $630 and $2,200 and have never had AM/FM reception problems in my rooms with any of them.
Tim
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atmosphere is right on this one. class d is just like any other amp. the sound is in the details of the designer. noise your dog can hear? old crt monitors exibit a whine at 36000hz. you cant hear it. Ive heard terrible class d amps and wonderful class d amps. issues are up to the amps design and all variants can sound great if designed well.
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