For example, I’ve read that GaN transistors are capable of switching so fast they literally eliminate dead-time and any resulting distortion caused by it. I would imagine that any good amp designer would believe that substituting these for the typical FETs used would result in significant improvements in the sound quality of any class D amps, or really any solid-state amps, that they’re utilized in. This is so correct, but so far it seems that only one has utilized this ability to take the higher switching speed up to 1.5mHz available with GaN (2.5 x higher than present), and that is Technics with their SE-R1, it does mean they had to use heatsinks to get it. Also it’s not that the higher switching speed alone make for the good sound it gets, it’s also that the "low order output switching noise filter" that all Class-D’s have to use, can now also be taken up 2.5 x higher, this then has no effects now down into the audible range, like the filters today do, which can cause phase shifts down to 5khz, and why many complain about something not right in the upper mids/highs. Cheers George |
When class D amp is switching between two discrete levels not the voltage but duty cycle is a quantity of interest and it is linear (no discrete steps). It becomes converted back to corresponding voltage thru averaging (filtering). Voltage gain of such amp is a function of switched voltage amplitude. |
Calling it a digital amplifier is a lot closer to the truth than calling an analog amp.
Not if you talk to a designer of a class D amp :) Switching is a bit different from digital. Digital has bits with which meaning (a sound signal) is imposed- how many bits are on or off and in what combination carries the meaning. The switching of a class D amp does not. Instead, it switches according to its encoding scheme. Gain is not represented by how many bits are on or off, gain is instead produced by the encoding scheme, for example in a Pulse Width Modulation scheme the gain is essentially the difference of the triangle wave vs the input signal. Thus it is possible to vary the gain of the amp by changing the amplitude of the triangle wave. This is fundamentally different from digital! |
toetapaudio:
"@noble100, f.y.i. In a recent test of various class D amps by someone we know in the business GAN amps did not come out top but were pretty high up. The other D amps were cheaper. My advice stick with your NC1200 module amps."
Hello toetap,
Sorry about the delay in responding, I had stopped following this thread but just checked back.
I've haven't heard a class D amp using the newer GaN transistors yet, I've just read some very positive reviews on a few amps using them. I'm not an electrical engineer or amp designer but it still makes a lot of sense to me that these very fast switching transistors are likely to only improve the performance of any device they're deployed in.
For example, I've read that GaN transistors are capable of switching so fast they literally eliminate dead-time and any resulting distortion caused by it. I would imagine that any good amp designer would believe that substituting these for the typical FETs used would result in significant improvements in the sound quality of any class D amps, or really any solid-state amps, that they're utilized in.
I'd prefer to personally compare some good class D amps using GaN transistors to my current D-Sonic M3-600-M class D monoblocs, which actually utilize Abletec ALC-1200-1300 and not Hypex NC1200 class D power modules, before passing judgement on their sound quality performance. I'm willing to pay more if I perceive these new class D amps as sounding significantly better
Thanks for the info,
Tim
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Calling it a digital amplifier is a lot closer to the truth than calling an analog amp. Amplification process is still analog, hence "Analog Amplifier". Connecting amplifier to DAC doesn't make amplification "digital". |
But even with an digital source built into the amp, its still an analog process. There are people who are going to argue all audio amplifiers are by definition, analog, but we don’t call DAC’s analog either. If an amp samples the input into discrete voltages, at regular intervals (i.e. has a sampling rate) and has an output controlled by those inputs, even if the last stage has an analog feedback loop, then it is 95% digital, and the last part had an analog feedback loop I call bunk on those who want to insist that makes the whole amp analog. Calling it a digital amplifier is a lot closer to the truth than calling an analog amp. Best, E |
And for the most part in the nCore/ICEpower/Pascal/TI world this is
true, though recent amplifiers from Technics blur the line further, with
an A/D stage, DSP processing and unknown amounts of analog feedback at
the outputs. Yes, that does add to the confusion. But even with an digital source built into the amp, its still an analog process. |
@jmolsberg, suggest trying to get a listen to some of the following class D amp brands, SPEC, Audio Nec and Mola Mola, that might change your mind. |
They are an entirely analog process.
And for the most part in the nCore/ICEpower/Pascal/TI world this is true, though recent amplifiers from Technics blur the line further, with an A/D stage, DSP processing and unknown amounts of analog feedback at the outputs. |
This amp opened my eyes what digital can do, I'm not a digital snob
anymore. I'm now wanting to look at more current digital amps to see
what there all about, mine is quiet but you do hear a little noise if
you put your ear close to speaker. Just for the record, the fact that class D and the word 'digital' both start with a 'D' is coincidence (which is confusing to the market)- its D because A, B and C were already taken. Class D amps are not digital although they are switching. They are an entirely analog process. |
i briefly used an ncore class D amp which did everything right, except keep me in the sweet spot. excellent low end, great highs, whisper quiet but it was certainly uninvolving to my soul. not to say this doesn't happen from time time be it a set amp or class a, but more often than not, i would lose interest rather quickly. as soon as i hear one that keeps me in the sweet spot, i am all over it. too many pros with the technology! |
Yup I'm with Mr. Creed as well. |
Agree with Paul Creed. I still have and love some old-fashioned A/B amps, but each year finds me with more D types around the house.
And I’m never, ever buying another 100-lb amp--or anything close--ever again. Those days are gone for good. And good riddance!
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I own many types of amps, different types of tube amps, different A/B amps, including the much referred to Benchmark AHB2 (which is actually A/B/H) and big classA Gryphon Mephisto monos...
I have no classD amp to date, but do believe that, given the proper design and parts, they are the future of amplification.
I have seen many good classD amps mentioned in the thread, but I dont think I've noticed anyone make mention of the relatively new Japanese brand called Spec. These are the very example of what classD can be; better than many high end amps, whether tubes or SS!! |
I always thought an amp needs to weigh 70 pounds with massive heat sinks and class D was sterile even though I never heard one.. I bought a used 2006 PS Audio HCA-2 with every mod Audio Reference Mods offered. It was cheap and was going in second system. I could not believe how fast and musical it is. It sounds like tubes in my system almost like a el84 amp but 150 watts, I am using a tube Preamp. The detail this amp pull out still amazes me eveytime I listen to it. It took 5 days for it to fill out but when it did it became big, tight and very fast with loads of information, I leave it on 24/7. This amp opened my eyes what digital can do, I'm not a digital snob anymore. I'm now wanting to look at more current digital amps to see what there all about, mine is quiet but you do hear a little noise if you put your ear close to speaker.
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I did notice the amps sounded most excellent after about 30 minutes of on time. I did not hear any further changes after that. For my part, the biggest change was in the first minute, right out of the box. Thereafter nothing terribly significant at any time. I will say that I'm quite impressed with recent offerings in the Class. |
Hey Folks. This journey includes late 70's ss McIntosh MC2200 (ugh) // Electrocompaniet Ampliwire II ..the starting period of good sounding sand // modded hybrid Moscode 300 with great NOS tubes - less truthful but nice tube magic // Muse 160 with Marigo tuning dot treatment - a bit zippy but worth the try, not the answer /// my sealed Salk monitors like power .. now what? For 3 years I had been on the lookout for a super clean NAD M2, the entry reference M Series, single box dac/pre/power that received consistently amazing press across many reviews. Once found, after taming a horrid ringing box and and silencing everything but the dac, this, by far, is the best amp in my system. Having gone to great lengths to lower the noise floor of my system (see posts,) the M2 drives subs deeply and cleanly, polishes the mid bass up through the mids with tone, dynamics and flesh; then tosses shimmer and sweetness to the top end. No single strength stands out and an abundance of micros are displayed in a calm, collected manner, as in real life. I probably listen 4 plus hours per day easily, finishing my day with top shelf playback of high resolution streaming or carefully selected ripped lossless files. No muss, fuss nor strain...calm. Three of my friends have built NCore D amps in the last few years. All three have or have had high end tube amps along the way and enjoy their NCore in their main systems. I have a euro friend that loves his Devialet Class D after lots of researching, mated with his Vivid Giya loudspeakers. If you are handy, the NCore kits offer tremendous value and sound. We live in exciting times. More peace. Pinthrift |
erik, your main point makes perfect sense, and should regardless of new kit.
I would not make a buying decision on a unbroken in product of any kind (what audiophile would?). While I currently enjoy my AA DPA-1, I also bought a pair of PS Audio M700s that were likely sold for the very reason you state.
When I quizzed the seller, he said they had < 100 hours. BUT, several reviews indicated that they needed closer to 200 hours and then were pretty darn good, especially at $3K MSRP, let alone what I paid for them.
Alas, many claas D amps haven't gotten the interest from review magazines. Still I didn't evaluate either of amps until > 100 hours break in, then another 100 using various mixing break in discs through the entire system. In both cases after 200+ hours, they got even better |
My main point about Class D power warm up really is just to avoid making buying decisions based on a cold demo as you may get an unfair experience.
I'm not suggesting you listen to the D's for two days. That's not part of my recommendation.
Best,
E
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Let me first say I think Erik's post is great and I totally agree.
I have a Channel Island D200 fed by a Rogue Audio RP1 tube preamp into Harbeth Super HL5plus speakers. In moving to this system from a class A amplifier a couple of years ago I listened to a wide variety of electronics and speakers (to the point I’m sure vendors went "not you again" when I walked in. I was extremely impressed with the Benchmark, but it was out of price range. In one store I was able to compare what is now my system with a pricier but very good sounding all tube system and neither my wife nor I could here a major difference. I went with the class D in part because I decided I wanted to move away from hernia level components, although the price per pound of class D systems is much higher than class A solid state, let alone tubes.
One thing I find missing in this and almost every other discussion is the type of music being listened to. At audio shows I would bring some CD’s and a USB drive to try to listen to music I was familiar with. I listen primarily to classical music and two of the most revealing CDs were a recording of Mahler’s Fourth Symphony and Ravel’s Piano Concerto in G, pieces I am also familiar with from concerts. I found that systems that sounded good with the vendor’s selected music were frequently totally inadequate with mine. At a show, the best sound I heard with my music was the Benchmark with a speakers whose manufacturer I don’t recall.
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FYI, the retail price of the 507ux and ux ii in the US were identical until the latter was introduced.
The only difference in the two is a refinement in the feedback loop.
Luxman makes a lot of different models, so it is easy to confuse one for another, especially going by pics alone. :)
Best,
E
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teo:
I understand your hypothesis and it is well articulated. The only issue I have is that I do not agree it is tightly intertwined with Class D operation. My AMR Phono stage is the best I’ve heard and it sounds great straight from standby mode but when that thing has been powered up for over 48 hours it is insane. Note that I said nothing about listening to it over this period of time, so it is not a brain-ear conditioning scenario. I’ve owned it long enough to know that is likes to be powered up for a while. It is why I power it up Thursday mornings as I head out the door and leave it powered until Sunday night. My Luxman EQ 500 could not care less ( if it could care :) about warm up, sounds the same from first hour to the last.
My Acoustic Reality Thaumaturges sound fantastic from power-up. They proved to me that class D can sound as good and in this case smoke many convential designs.
I have always believed garbage in garbage out. The power supply is the (in my opinion) most important thing. It is ultimately the power supply that is being modulated to create a facsimile of the original event.
I have three OTL’s, a S.E.T. (Reimyo PAT 777), a switching amp (mentioned above) and multiple push pull SS amps. I love them all and they all make music. Personally, nothing makes music like a well executed OTL but that’s for another thread :) |
Not being familiar with the Luxman 507 ux I decided to do a search
(it's a integrated amp), but only found the latest version, the 507uxII. Positive Feedback reviewed it in September of 2018. This is what PF had to say
>
"
L-507uXII is biased relatively richly into Class A operation, and indeed, while the amplifier never ran hot, it did get quite warm under normal operating conditions, so be advised that adequate ventilation is required. Having said that, the Luxman's sonics improved noticeably as it warmed up, and I typically left the amplifier powered up continuously to ensure optimum performance.
>
The L-507uXII likewise reproduced the treble range with a level of transparency and refinement that was unique in my experience. Cymbals, bells and other high-frequency instruments were reproduced with a clarity and ease that was utterly beguiling.
>
The only potential limitation to the Luxman's performance was in relation to its ability to recreate a soundstage. This is not to say that the L-507uXII was was a slouch in the soundstaging department. Far from it. The Luxman threw a wide, deep soundstage, populated with palpable images. However, image layering and focus within that stage was not as finely-drawn and tactile as I've heard from competing amplifiers.
"
MSRP $6500. The MSRP of the 507 uX looked closer to $4700.
There are a lot of really good sounding current tech (not accounting for GaN) class D amps (no integrateds) in the ux price range to consider. The highs could be abated with input op-amps and/or cabling.
Now I realize teo-audio was talking about his observation after his class D Ice amp was powered down for a couple days with what input buffer?), but who needs to do that when they are so efficient? Seems like a nothing burger to me
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teo, what class D amps have you heard?
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@noble100, f.y.i. In a recent test of various class D amps by someone we know in the business GAN amps did not come out top but were pretty high up. The other D amps were cheaper. My advice stick with your NC1200 module amps.
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TBC: Yes, the ear brain mechanism is very pliable, and constantly adjusting.
No, this theory is not a good fit for the multiple case studies reported.
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For an alternative possibility, see my post in this thread dated 6-20-2019.
Regards,
-- Al
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Your theory explains 1/10th of the evidence.
Equivalent of explaining that Columbus invented sailing.
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I don’t have to try again, I nailed it in a nutshell.
The sign on the audio world door says ’pursuit of the finest reproduction’,
it does not say
’reproduction good enough for most to call it outside of their capacity to resolve as better or worse... and therefore the best possible.’ |
Please, people, the ear and brain combination are a mutable shiftable changeable trainable device. Like the rest of your body, brain and eyes, etc.
While this is true, in general, it does not explain what I have heard. First, the time I went away from the system and turned it off for two days. I didn’t really listen to music while away. Second, going from a warmed up Class D to the Luxmans did not show the same audible issues as I did when listening to cold Class D. As others have noted, you don't have to listen to the amps for 2 days to have their sound change, just leave them on. When the Class D’s were cold they sounded cold and harsh. When I went from warm Class D to Luxman, I did not hear Luxman being warmer, or less harsh. I heard the Luxman being less warm, with more extension. Please try again. Best, E |
There was one significant operational difference, which others have confirmed. I don’t know why this is true, but the Class D amps needed 2-4 days to warm up. The Luxman needs no time at all. I have no rational, engineering explanation for this. After leaving the ICEPower amps off for a weekend, they sounded pretty low fi. Took 2 days to come back. I can come home after work and turn the Luxman on and it sounds great from the first moment. Retaining of the ear. The ear is mutable. Thus the retraining of the ear to deal with class d. Please, people, the ear and brain combination are a mutable shiftable changeable trainable device. Like the rest of your body, brain and eyes, etc. Yet, importantly..the Luxman with classic amplifier design, required no time at all to adjust to.
What does this tell you? It tells you that the Luxman is more natural and correctly addressing the ear’s natural function ---all in a way that the ear resolves sound.
The class D amp is a fight to get the brain to ignore it’s follies and have the brain ear combination attempt to find resolution hiding in the noise and distortion pattern that is foreign to how the ear works. Why would any sensible human being be up for that? That’s what it tells you. It tells you that the class d ’bear’ can dance in a way that the humans can recognize as being akin to a dance, but really is not a true and actual dance. Just similar. ’the bear looks like it is dancing’, in the same way, ’class d seems to be reproducing a signal’ Kinda sorta maybe. But not quite as good as other, older tech. As the experience, when properly considered ...so clearly shows--- Class D is not more natural or better. So why fight with it for another 20 years so it can get closer, when you are already there with another technology? It’s like saying, "I can row my boat across the lake really really well..so now I’m going to cut my arms off and do it with stumps. And I’ll eventually, maybe, somehow.. be good enough to win the Indy 500 of boating. And finally be back to where I was at, before I cut my arms off." The logic and thinking is dubious at best and insane at the worst. |
noble100 said..."the Element 114 priced at $15K/pair." The 114 is a stereo amp,not mono. And I agree... the Veritas monos are a fantastic sounding class d amp. |
Hi Peter (bigkidz)
Tommy’s Cherry amps are very good not only for being class d but, overall to all classes of amps.
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Can SMPS’s work? As a software and electrical engineer, I would like to think yes. I build power supplies for my internal projects. I want them to be as good as a regulated linear PI filtered supplply but as of today HECK NO! They are RF stations inside your box.
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Tweak1:
You get it.
If someone has “huge” current spikes at 120hz in a linear supply then they suck at power supply design, SMPS’s are miniature radio stations inside your amps. It’s called a PI filter.The guy who owned the H2o amp company understood. My unc has owned the Rowland 8t amps and the model 9’s along with the Rowland 102s amps , don’t even ask.., ok I’ll tell you the 102 S SUCKED! Others? pretty good:)
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@snapsc - thank you for the follow-up. I know Tommy pretty well. He came to our audio group many times. I guess I should reach out to him and get a pair to audition. Thanks. |
@bigkidz not sure if this is a reasonable price...size....or weight....but the 2Cherry with added rail capacitance...standard faceplate....standard gold binding posts....is going to be 14"w x 10" deep x4" high, weigh about 16lbs and cost you about $2700...give or take...with a 30 day trial period...easy decision for me....I didn't send it back. https://www.cherryamp.com/5-channel-ampmore spec info, etc. here https://www.audiocircle.com/index.php?topic=162524.0 |
mijostyn
What are your loudspeakers that are so difficult to drive?
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I have supported a certain type of database technology for most of my career. Good product. But about 25 years ago they came out with a very bad version of the product and then a bit slow to rectify the situation along with a few other issues. There were some very large companies that this impacted greatly. The software company quickly got things lined out but the bad press took many many years to overcome and in some ways was really never completely shed.
Can't argue though that stereotyping is a real time saver.
I like my little PS Audio S 300. And I agree, I think it do sound better after being left powered on.
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bigkidz, The Merrill Veritas mono-blocks at about $10K/pair are one of the best class D monos currently available. They also just introduced some even more expensive monos that use the very fast switching and new GaN transistors instead of the traditional FETs. These are the Element 114, 116 and 118 models that are starting to get rave reviews but are expensive, with the Element 114 priced at $15K/pair. I don't consider these reasonably priced but I'm not sure of your budget. If you'd like some very good class D amps reasonably priced, I'd suggest considering amps from D-Sonic. They offer very good stereo and mono-block amps with even their top models priced well under $3K. I've owned their older model M3-600-M monos for about 4yrs and they are extremely good powering my Magnepans. The latest model of these are the M3a-600-M priced at $2,150/pair and the top of the line monos are the M3a-1500-M priced at $2,750/pair. They also offer stereo amps for even less. Here's their website: :// www.d-sonic.com/amplifiers I'd suggest calling and discussing with the owner, Dennis Deacon, which amps would be the best fit for your Vandersteen 5As. A 30-day trial period is offered on all their amps. |
Stibi,
I think that those amps may have done the same to a lot of linear amps too though. :)
Best,
E
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Few months ago I decided to change my amp and I auditioned one class D (Devialet expert pro 1000) and one pure class A (MBL M204 mono blocks) head to head in my home system. My initial strong preference was towards the Devialet as it looks gorgeous (especially that remote), has tons of features, takes almost no space and although quite expensive was still below the MBLs price tag. Unfortunately the head-to-head was a revealing exercise - I am still not sure whether the Devialet was not as good as advertised or the MBLs were just to amazing, but the difference was obvious and not in favor of class D in that very case. After the first Wow effect of the Devialet I started to realize that I miss the sweetness of the music, it was kind of everything is there, but cannot touch you. MBLs produced much more refined and enjoyable sound with every kind of music, especially jazz. So I ended up with two huge heavenly sounding monster heaters in my room. Next time I hope to find a more convincing class D amp :) |
I have a pretty well reviewed by older class D amp, the Wyred4Sound ST-500. Bought it used in 2017 and have been every pleased with it. BTW, my only reason for going class D was my cramped desktop space that has zero room for a trad A/B amp. I actually installed the ST-500 on one side to save space--it makes next to no heat at all and nothing bad has resulted.
I've heard this amp with some relatively high resolution speakers (ATC SCM12 Pro), and I hear an above average sound, top to bottom--none of the class D nasties people speak of. It's somewhat warm & slightly bassy, which is OK by me... |
Let me clarify myself, a little. While I like Class D, and in some cases a lot more than certain Class A amps, I do think the ability for them to emit noise back into the power line or radiate it to nearby devices is not zero. So I advocate the uses of shielded power cables and using multiple filter banks to isolate them from other gear. A detailed coverage of my thoughts on the matter are here: https://inatinear.blogspot.com/2019/04/power-management-for-frugal-audiophiles.htmlBest, E |
OK I have a question. I have not listened to a Class D amp in recent years. Way back I listened to the NuForce, Gilmore Raven and Channel Island Class D amps. The CI was nice sounding and the Gilmore was the clear favorite. The Nuforce did not impress. A good friend on mine has the NuForce and upgraded the internal power supplies. He claims they are much better and loves them in his system. He visited me a few months back and plugged them in my system. I am using an old Counterpoint SA-100 modified with better caps, resistors, added filter choke, etc. The Counterpoint in my system was way better than the NuForce and I was pretty disappointed. We did not really take the time necessary to try to see what was up. Since then I have recently modified a few Counterpoint amps with bi-polar output transistors, class A output, all point-to-point wiring and those amps make my modified Counterpoint sound pretty bad, slow, no dimension, less details and dynamics, etc. I actually knew that those amps would be that much better.
So my question is, if I was to try a current class D amp for a reasonable price, what would you recommend that I try out? I would love to get an amp that weighs 8 pounds and sounds good. I will have the opportunity to hear the Merrill amps next month to see how those sound.
BTW, I can build them if there are kits that sound very good. I just have not had the time to research them myself at this time.
Thank you and Happy Listening.
My system: Audiomeca and Metronome transports, my own components Vu Jade Audio 6SN7 preamp, Direct heated Triode DAC, Tube phono stage, and my own design Counterpoint power amp SA-100 and SA-220 which are really no longer Counterpoint designs, just using the chassis and transformers. Speakers are Vandersteen Model 5As. I think you can see my gear on this site under by member ID. Thanks in advance.
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audiofun:
I used the self-powered version of the ICEPower modules, and I simply have not experienced the differences you did.
I did keep the amps far away from other gear though, and used ferrites on the power lines.
Best,
E
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I joined the Audio Circle and asked a few questions. I like the philosophy of the company very much. Low overhead, straight forward well executed chassis. The 1500 watt, quadruple rail version of the Megaschino is $17,000/pr. Not cheap! I still can not find any info on how he is sampling and why. I think he holds that information close. He has a thread on planar speakers which seem to be an interest of his. I described my speakers and related that I would like very much to hear his amps. Not many amps drive my speakers gracefully. We shall see how he responds. |
Great thread Erik.
I've wondered about said deficiencies with class D also and wondered if it's because this class doesn't sound exactly like typical SS nor typical tube amps. Just my own limited experience but I don't hear these horrible deficiencies either.
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Here is an interesting take on Class D amps: I picked up a pair like new Anthem M1 Monoblocks from a very wealthy guy who decided that he just had to have a pair of Levinson 53’s at some god awful price point. I got a really nice deal on the pair in mint condition and with later serial numbers, consecutive of course. I put them into service against my Parasound A51 Halo which is 400 watts per channel at 4 ohms vs. the 2000 watts per channel of the M1’s (when fed with dedicated 240V mains). It was love at first sound; these things blew away the A51 in all respects, it was no contest. I have not used the A51 in two years now, its occasionally used as the power amp for a center channel when I run the TV.
I spoke not too long ago with the guy who sold me the amps and asked how he’s enjoying the $35K amps he bought and he told me he made a major mistake selling me the M1’s, they are actually better than the Levenson’s! That really surprised me, but then again, it doesn’t as I have not heard anything as beautiful as the M1 monoblocks..... Class D of course
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From my experience with several Class D amps, newer Class D amp designs in general seem to have very effectively resolved the noise issues that can otherwise be associated with SMPS. I’ve seen this with my Class D amps ranging in cost from <$100 to those going for several thousand dollars. Does not seem to be an issue anymore if done right. Not so much the case as recent as just a few years back though I’d say. |
