I thought it was time we had a pro- Class D thread. There's plenty of threads about comparisons, or detractors of Class D.
That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.
For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.
No matter how nicely you ask George to start his own nay-sayer’s thread, he’s always going to share his impressive collection of articles about how planes can’t fly.
No sir, they are too heavy and completely unreliable. Plus, you will fall off the edge of the world if you go too far.
God help those of us who want to talk about how much we like Class D, because there is George telling us we are wrong. George would skip his own chemotherapy treatment to come and tell us this.
As is the case with most of what we are taught as our understanding, we must be willing to surrender our understanding to gain insight into truth. There will always be those who refuse to surrender their understanding to learn truths. And that’s ok. We just need to acknowledge it for what it is.
Oh, I don't mind that. I'm not hear to convert anyone.
But I think it shows a great deal of class when you speak your peace and then leave the subject alone for those who are contributing in a positive fashion.
Oh, I don't mind that. I'm not hear to convert anyone.
Why then interject with personal backlash, when
celander and I, were just talking about amps that are most capable of driving the Duntech Sovereigns, and I just happen to see and post a link to amps that can and couldn't, and it just happens that Hypex N-Core Class-D couldn't drive them. Here it is again as it's lost now on the other page. Duntech Sovereign's suitable amps that drive them.
I understood your input to me as not trashing class D designs, per se. They differ among themselves as much as designs within categories of other topologies do. Sometimes the output devices (in this case—for our discussion—Duntech and Dunlavy SC speakers can reveal and distinguish those designs as being better matched over others, whether class D or class AB (tubes, for example).
Even folks here who rave about their preferred designs within the class D family would concede that point. Their raves are within a given reference context.
There’s a vast number of class D amp owners literally throughout the world that have absolutely no doubt about whether their amps are extraordinary performers in their systems. Yes, the great majority of them have switching frequencies in the vicinity of 500 KHz and may not possess the latest and fastest FET transistors in their output stages. Most of them are probably unaware of this but likely wouldn’t give a hoot if they were aware because they sound so incredibly good in their systems. The owners of one of the many current or recent crop of extremely good class D amps just hear the obvious; their amps have very low distortion levels, dead-quiet background noise levels due to very high signal-to-noise ratios, excellent frequency response throughout the entire audible range, very good dynamic range, very good channel separation along with the ability to handle very low speaker impedance levels and deliver more than enough power to properly drive any speakers. Additional class D amp benefits include small size, low weight, high electrical efficiency that results in low electricity consumption and very little excess heat and all at very affordable prices. What’s not to like, right? Despite all the benefits of good class D amps described above, you continue to suggest avoidance of these amps until they utilize switching frequencies in the mega-Hz range and the latest and fastest generation of super-fast FET output stage transistors . Will higher switching frequencies and faster FETs enable class D amp performance to get even better? As a user of several exceptionally good class D amps of recent vintage, I find it somewhat difficult to imagine how their performance could significantly be improved but I’ll keep an open mind until I give one a good listen in my system. Until then, however, I. would advise anyone considering a class D amp that it makes little sense to wait for possible class D amp perfection. Nobody needs to deprive themselves of high quality sound by making the same mistake that georgehifi consistently and inexplicably insists upon: making perfection the enemy of the extraordinarily good.
I love my Audio Alchemy DPA 1, which is said to be a hybrid, due to an FET input stage, I guess. Last night I swapped out a silver over copper Surf XLR for an old PS Audio (mid model) and was floored at the much needed warmth that was hiding in the amp
@erik squires Eric , I purchased a used pair of Bang & Olufsen Penta 1 loudspeakers a few months ago on craigslist. They are circa 1989 . They are active with class d amps inside . These are in no way bright or fatiguing , things I have associated with older class d amps . Looking to find out how and why this could be ?
This is probably over simplifying or incorrect, but maybe their maker voiced the speaker to the internal amps? Or did the amps only power the bass drivers?
I don't find good digital amps bright or fatiguing today.
In the late 1980's I was listening to some digital amps that sure were though!
I don't know how old the B&O/ICEpower designs are, but that's what I listen to every day now. :) It's quite possible the speakers, designed as integrated wholes, eliminated issues with the rest of the Class D crop.
I will say that the Class D amps I was listening to wwas through entirely different speakers, TAD pro studio monitors from the time, so that could have been a horrible match overall.
maplegrovemusic They are active with class d amps inside . These are in no way bright or fatiguing , things I have associated with older class d amps . Looking to find out how and why this could be ?
This may help, but the reviewer found it
a bit dry and lacking in harmonic complexity and bloom in the upper midrange, a bit dry in the mids, and maybe even somewhat aggressive on top. It's one of the first, commercial Class-D that came after the original Class-T (Google these also as they only used N channel fets which allowed in some cases a higher switching frequency) The 18 year old Sharp SM-SX100 Class-D, if you look at the 4 ohm frequency response it's already starting to roll off the high frequencies at 2khz, and the simulated speaker load is not much better. https://www.stereophile.com/content/sharp-sm-sx100-digital-integrated-amplifier-measurements
@atmasphere can you give us any information on when your Class D (not digital) amps might be ready for prime time? Will they be stereo or mono-blocks? Estimated price?
celander: "
I suspect some type of class A-class D hybrid will likely be the future for all class D topologies."
There are currently class D amps using the topology of both transistor and tube analog class A input stages combined with analog class D switching power amplifier stages. I've never auditioned any of these amps but did read a very good professional review on 6Moons about the French DeVailet solid state hybrid integrated class A-class D hybrid.amp. The reviewer loved it but it was uber-expensve like most of the best traditional amps are and always have been.
during the past century and possibly for another century. Perhaps the most significant aspect of the many good class D amps is their affordability. From my perspective, the egalitarian nature of class D technology is a beautiful thing, bringing extraordinarily high sound quality to an increasing number of individuals' systems that otherwise would not be able to afford and experience it. I'm hoping the future of class D topologies is a bit more interesting than just relatively expensive hybrids. The inventor/designer of both Ice and Hypex NCore class D amp module technology, Bruno Putzeys, has stated he's able to design class D amps that sound like any traditional class A, tube or hybrid amp topology desired. I wonder if he could design an affordable class D amp that could mimic the sound characteristics of the best current and past examples of traditional amps, along with the best example of independent class D amp sota efforts, that is user selectable. A guy or gal can still day dream, right?
Hi guys is this thread redundant? im thinking of the Peachtree Nova 150. Any owners? im wondering why they’ve gone back to Ice for this line. Didn’t they use Hypex previously? Also won’t eGaN make all these redundant quite soon? Cheers
I remember the Peachtree importer a friend of mine here in Australia demo’ing me a pair of midrange floor standing Focals to be our Audio Clubs "house" speaker, which he also imports, as well as Krell amps.
He was using the Peachtree at the time because he had no Krell’s handy, and quietly said to me the Peachtree isn’t very good, you should hear these Focal’s with the small integrated Krell feeding them.
I never heard one. Ended up with the NAD equivalent and very happy. They use a hybrid , almost like a Class H, Class D and Class A in one, designed by Hypex. No, the new transistors won't make anything obsolete, but sure will make things more expensive.
Hello All, I was long hoping to evaluate the Rowland Daemon 1500W
Superintegrated amp. Could a class D integrated fulfill my yearning for sonic nirvana, or would Daemon leave me pining for the wonderful music of my separates: Rowland Aeris DAC fed by the ultra-capacitor-based PSU external power supply, driving my beloved M925 monoblocks? Eventually, a Daemon review unit was delivered on February 28th. I Started
break-in the following day, and have been scribbling my listening notes since…
The writing project will continue for at least a few months, until the
device has stabilized, and I have exercised several of its many input and
output features. I have been waiting for a long time for this 99Lbs single box
critter. It is Jeff Rowland’s integrated statement. The DAC + Preamp + 1500W/8
(2500W/4) dual-mono power amp in a single chassis measuring 17.5” x 15.25” x
9.5” is sounding amazing after just a little more than a couple hundred hours of break-in.
Discovering the phenomenal musical beauty that Daemon produces is being a fascinating experience… Already I am stunned by Daemon's power reserve and unreal tonal grace. Join
me to chat about my adventure with this integrated flagship around its new Audiogon watering-hole:
GaN transisitors don’t cost any more than mosfets. People are charging more for GaN amps because it is the latest buzzword and they are first out so they gouge you. The EPC GaN fet recommended by EPC for audio use costs $1.05 each at 100 quantity. Hardly expensive. At the most 4 per channel....so that is $9.
GaN amps will be available from China for a few hundred dollars.....I have no doubt. However, they have to design the circuit from the ground up.....so will take a little while to come. The big manufacturers are slow and conservative (Hypex, IcePower, Pascal, etc.). It takes a sledgehammer to get these guys to try something new and then it takes years for them to develop it. It will be just small companies for awhile with GaN amps.....but hopefully, the big guys will get on board. TI and Infineon, etc. make class D amp chips as well. Maybe they will be first to come out with a GaN version......then you will see things like this:
Personally, I think it's a horrible thing to price out a product based on component costs.
I think everyone would be horrified if we did this consistently across audio.
There's more to a high frequency design than the cost of the transistors. PCB layout must be done meticulously, and test failures common, so R&D matters.
Still, having said that, Class-D amplifiers are quite good already. Better than some Class A amps, worse than some Class A/B.
If there are actually audible benefits to GaN based amplifiers I look forward to hearing them.
If there are actually audible benefits to GaN based amplifiers I look forward to hearing them.
There should be. GaNFETs are generally faster than MOSFETs (although MOSFETs aren't done by any means) and so the use of GaNFETs means you can run the amp with less dead time. Whether a designer takes advantage of this fact is another matter but generally speaking GaNFET amps should sound better as they have less distortion on that account.
Whether a designer takes advantage of this fact is another matter but generally speaking GaNFET amps should sound better as they have less distortion on that account.
@atmasphere
As you are well aware, I’m kind of touching on an issue of specmanship that that affects us with all amps. Can we hear "better" when you go from 0.01% distortion to 0.001%? I know distortion can be reduced, which technically means more fidelity to the input signal. What I don’t know is that this alone is audibility, let alone desirable.
Like Tube amps, or Pass (who makes it clear this is his goal) the distortion profile may have more to do with euphonic capability than merely lower distortion.
Like Tube amps, or Pass (who makes it clear this is his goal) the
distortion profile may have more to do with euphonic capability than
merely lower distortion.
He is certainly right in that regard IMO. But we can hear that difference provided the distortion profile is also correct. The problem is that in most cases the difference between 0.05% and 0.005% isn't the issue- the fact that the distortion that is there is mostly higher ordered stuff that is highly audible even in those trace amounts. The correct distortion profile can mask those higher orders making the amplifier easier to listen to. But a class D amp tends to have a different distortion profile than a traditional solid state amp. Many of them using PWM encoding tend to have lower ordered harmonics too- which is the profile you're looking for.
The technological backflips and design hurdles inherent in making Class D viable seem challenging to every designer who bothers with it, and clearly some are more successful than others. I think cheap Ice modules in a box or whatever Atmasphere Ralph is designing may work for many (I have one in an Ampeg 350 watt bass amp a friend traded to me...matches a vintage looking speaker box I already had), but replace my simple little single ended tube amp? Why? Less heat maybe, less distortion perhaps, more power that I don't need...and the biggest thing by far, an amp that likely doesn't sound as good to my ears as the harmonically rich and musically profound tube amp and preamp I'm using now. The "sounds like tubes" argument for some items, including the Schiit Aegir (not Class D but I'm tossing it in anyway) I recently auditioned and sent back, never really sounds like tubes (Nelson Pass tries, and the things of his design I've actually heard do sound real nice...but...)..."drives like a sports car"...right...until you drive a sports car.
but replace my simple little single ended tube amp?
First, @wolf_garcia , I applaud you for being willing to expose your audio quirks without fear. I wish I had that kind of personal courage. ;-)
But that’s just it. If you love the LP sound, only the LP sound will be good enough. If you have a particular niche of amp, no other amp will sound as good. It’s not proof Class D is behind the best solid state amps. If you have a love for 30 watt Class A, same thing. It's a bit like comparing all restaurants to mom or dad's home cooking. Kind of unfair to rate them that way, unless of course your mom (or dad) was an absolutely terrible cook.
As I always say, buy and enjoy what you like, even if it’s’ some quirky SET or full-range with a giganormous bass horn. That’s fine.
But I think it’s unfair to diss Class D because it doesn’t sound like a SET. Among large solid state amps, I don’t know anyone who can listen and say "Oh, that’s a Class D amp, I can tell because....."
It’s one of the first, commercial Class-D that came after the original Class-T (Google these also as they only used N channel fets which allowed in some cases a higher switching frequency)
I wonder if this is the reason why I only like Tripath amps under Class D category. Class D amps other than Tripath, give me kind of fatigue after 30 minutes of music. When I put my Tripath amp back, I can listen to my Harbeths for hours.
It seems that many folks hear one or two examples of a particular technology and if they like them then they equate that like across that platform. And vice versa some do not like the one or two examples of a tech they've heard and so they think that all examples in that tech sound bad.
Erik, you and I, Guido, and Ralph (and I'm many others) know that Class D can sound good. Obviously Ralph thinks so since he is working on bringing a Class D amp to the market. We also know Ralph made his mark in tubes and so working to offer a Class D amp he is basically stating that Class D can sound good, maybe not like tubes, but good in an of itself.
For those who've heard Class D and don't like it, I challenge you to go listen to Mbl or TAD. They both have Class D offerings that are very very good. You can't judge a book by its cover or its categorization. Don't listen for the Class, just listen for music. You may be very surprised and preconceptions may just be shattered.
He loves them...bought them...replaced his tube amp.
AGD says they are using the IRS20957S PWM driver chip ($2.01@100).....and probably then a pair of $1.05@ GaNs on the output. You can see most of the circuit inside the tube in the above review. This means anyone can do this for practically nothing. Putting the circuit in a tube is just a gimmick. If they put that board inside the box and it was made in China with all the very same parts it would sell for around $1000 for the pair of mono blocks....no kidding AGD are using LM4562 op amps ($1.00 each) on the input. There are no expensive parts in this amp. You can see the very good sounding inexpensive Wima caps and Nichicon caps.
But we don't want to wait for the Chinese version that sounds as good for $1000......no, let's buy the one with the board in a tube for $7000......heck, we have money to burn.....he he. You see, fun times for cheap are right around the corner. Of course, anyone can make an amp similar to this....if someone else here is the US made it and sold it direct....probably $2500 the pair.....still...way less than $7K.
Would require more technical ability and energy than I have and my health could be better (I will leave the amp making to the younger guns) .....but mostly I am writing a book that hopefully will make more difference in the happiness of people than a better inexpensive power amp. I want everyone to be happy!
I also have high expectations for the use of faster switching GaN output transistors in class D amps since they have the potential to eliminate dead-time, which even further reduces distortion, which in turn, typically results in improved sound quality. I've been using good quality class D amps in my combo music and HT system for almost 6 years now. In my opinion, they're the best option for attaining hi-end amp performance quality at an affordable price. In my experiences with good quality class D amps, I've discovered their most unique quality is that they have no sound qualities of their own. They just faithfully amplify the inputted signal without adding or subtracting anything. They're like the audio amp ideal of a "straight wire with gain". Due to this extreme neutrality of class D amps, I've come to the conclusion that the most important factor determining the overall sound quality level of a system utilizing a good quality class D amp is the sound qualities of the preamp chosen to pair with it. This neutrality also means the overall system sound quality contributions made by source components, and even interconnect and power cables, will be readily apparent and need to be chosen carefully, too. I've not yet listened to a class D amp utilizing the much faster switching GaN transistors but am looking forward to doing so, hopefully, at an affordable price. Based on my experiences with good quality class D amps, however, I suspect the use of GaN transistors will result in these amps being among the most neutral ever produced. Choose your preamp, source components, interconnect and power cables appropriately.
,l with In my experiences with good quality class D ampsThey just faithfully amplify the inputted signaout adding or subtracting anything. They’re like the audio amp ideal of a "straight wire with gain".
Sorry they don’t look the same, just look at any 1-10khz test shot of input v output wave form. And then without their output filter, the input wave form will be unrecognizable from the output, because of the HF garbage, and melt your tweeters silently in a nano second.
It’s like a customers preamp I had to work on, the owner said it sounded little bit hard, a quick look on the scope showed the output wave form looked just like the input wave form, all looked fine?.
Then I looked with the scope in the center of the preamps circuit, and found the wave form unrecognizable from the input with the amount of hf garbage on it. That center amplification stage was oscillating its brains out!!! And all they (manufacturer) did was to filter it out at the end stage, instead of fixing the source of the problem.
I compensated the center stage so it didn’t oscillate anymore and removed the end stage output filter, and the customer was happy.
But you can’t do this with Class-D, so the only thing to do is to raise the sw noise in it even higher (1.5mhz) so then the output filter then can do it’s job fully without any phase effects down into the audible frequencies. Then a Class-D’s input wave form will be much closer to matching it’s output wave form.
"straight wire with gain"
There is no such thing as straight wire with gain. Every single inch of wire sounds different from every other kind of wire and even the directionality of the wire makes an audible difference. Every single thing inside a power amp (class A, B, C, D or whatever) changes the sound. This is why every class D amp sounds different from every other one. They don't all have no sound or the same sound. I did 14 mods to the IceEdge modules to make them sound more dynamic, musical, extended and transparent. There is no end to infinity. We have not reached any sort of final class D sound orgasm.. If class D sounded perfect with mosfets, then why would we be looking at GaNs? Nothing is perfect on this plane....all is perfect in spirit......all is suppose to be this way....perfect in its imperfection.....and always we strive for more perfection.....hey, its fun!
Erik, three years later, and still going strong, excellent thread. Class D is the bomb, and your thread would seem to amplify that message. I purchased a D.A.C. older amp for my first try at Class D, A/Bs left something wanting. My Signature Technology is a very nice tube amp, the cymbals never sounded right. The DAC4800a was my first thousand dollar amp. It has been a delight ever since, so much so, I purchased a used Maraschino 60 volt model. Absolutely delighted with each. The 4800a uses a toroidal transformer, the Maraschino a linear power supply. Currently saving my money for another 60v Maraschino, will have to be new as these amps seldom come up in the used market. In another class compared to my Acurus or MTX Soundcraftsman. Use any adjective in the audio lexicon and these fit and fulfill those descriptors. I would really like to hear a review about the DAC amps from you. With respect, Jerry.
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