I have recently paired an Audio Research DS225 Class D amplifier with an Audio Research tube preamplifier (SP8 mkii). I cannot believe how wonderful and lifelike my music sounds. The DS225 replaced an Audio Research SD135 Class AB amplifier. Perhaps the SD135 is just not as good as some of the better quality amps that are out there, but it got me thinking that amazingly wonderful sonance can be achieved with a tubed pre and Class D amp. I have a hunch that as more people experience this combination, it will likely catch on and become the future path of many, if not most audiophile systems. It is interesting that Audio Research has been at the forefront of this development.
I build and sell class D amplifiers so I admit to being biased.
The transparency combined with the dynamic reserves and bass grip are gaining many converts in the audio world. I have customers selling mega-buck mega-amps to switch over.
The two best class D technologies available today require a custom designed input circuit. If you get this right, you rock.
Efficient speakers with small single ended tube amps don't require much juice, and for my money sound more like music. Many with all SS gear leave it on all the time thus actually wasting juice, and I assume most tubers don't, unless by accident like when they pass out or die. I mentioned I have a Class D 350 watt Ampeg bass amp (of the Porta Flex amps, this is the smallest) screwed onto the top of a "Porta Flex" bass cab, and it's very cute...sounds fine, which leads me to suggest counting the tube amps available in any high end audio store, and then walk into a guitar store...notice anything? Dozens of tube amps from tiny to gigantic. Modeling amps, small SS practice amps...none sound like a classic tube guitar amp, and it's likely they never will. Why is that?
There is a difference between liking a particular combination and believing it is the future for over half the community.
And where does obscene money begin? I understand the price point of D class amplifiers. Money is relative IMHO, I tend to think of my system in terms of percent of my vehicle cost.
I've never listened to a class D amp but I own a class A amp that I love so there's no reason for me to. I'm good for many years and with all of you buying them, I'm sure they'll be amazing when I'm ready.
How many people have had a good run of class D amps and switched back to A/AB? That's what I'm interested in. They say over 90% of Toyota Prius owners only ever own one Prius, meaning they go back to a full time gasser. This morning on the morning show they said electric cars are not going to take off for another 15 years. Where are we at with class D right now? Everyone keeps saying that the future is class D but where is that in the future?
" Where are we at with class D right now? Everyone keeps saying that the future is class D but where is that in the future?"
It's already here and has been for a few years. When the CES happens this year I'm not sure we will see any Class A amplifiers on the main floor, maybe not any at all. Don't quote me, I don't have an exhibitors list in front of me. What I do have is an apartment a few blocks away from the CES and have seen HEA, in general, go from cutting edge front and center to almost invisible at the biggest electronic show in the world.
I don't think Kosst saying class D is a fad resonates much with innovative audio companies of today. I also don't think the current young generation of audiophiles care to see huge amplifiers sitting in the middle of their living rooms. I may be wrong, but I haven't seen this. A bunch of old farts, as we are, aren't going to tell the younger generation much about the way they are setting up their stereos.
I'm not trying to offend but the OP says "future" not nursing home bencher audiophiles. Trying to say these massive space heaters are going to somehow become the future is not very realistic. I have many amplifiers, some dating back to the 60's. They're all enjoyable for one reason or another. I'm listening to one from the 70's as I write this. Even though I'm enjoying this amp I can hold in my hand this other little Class D amp and realize the truth. I can also setup this little Class D, tune it, and be right in line with my other amps. Now, I can choose any of my amps to listen to, but reality is reality.
" Where are we at with class D right now? Everyone keeps saying that the future is class D but where is that in the future?"
I do too, and it will come, when they've got it all right, with no compromises. When they get rid of it's "flaws".
Every detractor of Class-D never complains about it's bass or upper bass or even lower mids, it's always about the upper mids and highs.
Technics with their $20k SE-R1 have broken the Class-D norm and got most of the way to fixing these "flaws", by using a switching frequency at twice the norm, instead of around 600khz they've gone with very special GAN components to double the switching frequency to 1.5mhz, (3mhz would be better) this then allows the low order switching noise output filter to do it's job completely without leaving any effects and any left over switching noise artifacts within the audio band.
no class D amp will ever compete with a class A amp. It's simply impossible to build a class D amp that reaches out to
500,000Hz and doesn't burp driving DC into a 2 ohm load.
This is the logical fallacy of the "excluded middle." Audio amplifiers aren't required to deliver DC. Even many excellent conventional amplifiers would fail to meet this absurd, arbitrary spec.
George I have looked over that Technics technology and hope that it may trickle down into more affordable components as right now 20k is a very hard sell to non believers.
Hopefully somebody can make it happen for a lot less dollar!
This type of argument comes up quite often. Class D vs A, AB,or Digital vs analog, or different speakers, amps, etc.
people have their opinions and there is nothing wrong with having an educated opinion. having an opinion with know what one is talking about is quite another thing.
I haven't seen one really wrong thing on the posts here. people just have opinions. Some based on equipment that they have heard and others on their past experiences.
Class D has been around for quite some time. In car audio it was really the only way to go to get the power output needed. you can't do it from 12 VDC. So switching power supplies were mandatory, and there was/is/are some quite good car audio amps out there.
Home audio was quite another thing. switching noise was a serious problem. Finding output devices that could handle the high frequency switching with low/no noise was hard and people could hear it.
Now, Class D has for home audio has come a long way. No way Jeff Rowland would delve into Class D if he couldn't do it right. I spoke with Jeff Rowland at the 2018 RMAF about this and he told me that they will always produce non class D amps.
Could be market forces for both classes at work.
Many homes simply don't have the space for large amplifiers and audio systems. Period. That forces the manufacturers to come up with serious alternatives. Class D was that alternative. However, back in the day, doing direct comparisons between standard Class A/AB amps and Class D amps with the same system and music, the Class A/AB amps won hands down.
That's not the case anymore.
Remember, back in the day, Class D was simply not very good. The power supplies and devices were not "there" yet. So, to get proper class A/AB amps right, proper power supply design was absolutely necessary. skimping on power supply design automatically determined that the amp would be bad.
This was why amps weighed so much. read Nelson Pass' articles on power supply design. Large transformers (read heavy) were mandatory, proper filter caps (also heavy) and lastly, proper power supply regulation (almost as complex and heavy as the power supply) were required. It almost came down to a certain weight per Watt value.
manufacturers didn't' do that for the hell of it. for proper amp design, it was mandatory.
Class D amps gets one away from very large/heavy power supply designs. That is not to say that certain manufacturers won't still make the casings extremely heavy, or the heat sinks, etc.
The problem also arises in that most manufacturers don't make their own transistors and tubes. They have to source them from others. So you either buy from what is available or you design based on your specs and get companies to make them for you to your specs.
My point is that Class D isn't necessarily the future. It is "a" future. There will be other technology coming that will supplant class D also.
But, if you think Class A or AB is going away, don't bet on that.
Space limitations, size, savings on power supply design and costs are the driving forces behind class D.
I've heard some pretty darn good class D equipment. What I don't understand (actually I do) is why they are priced so high. They don't have the extremely expensive power supply and heat sinks, so where is the expense?
But are they good? yes? Better that like valued Class A or AB? not so sure. some yes, some no. Same can be said for Class A or AB.
Are the top of the line (costs no object) Class D amps equal to or better than the top of the line (costs no object) Class A or AB amps? that I seriously doubt at this time.
But, one never knows do one?
But, stop dissing Class A or Class AB amps. The massive weight and size. Power supply design and massive heat sinking and regulation dictated this was necessary. Class D was not good back then. So, if manufacturers have they plants already set up for Class A/AB and costs is minimized, why change immediately? Many are very slowly moving to Class D, but they aren't getting rid of Class A or AB.
sorry for the long rant, but I noticed many getting very heated and I felt a need to slow things down.
If you have no space and don't want large heavy space heaters and you want very nice/decent sound, Class D is the way to go.
But if space isn't an issue for me, I would have to hear the Class D amps side by side against the Class A/AB amps before I make the switch. Get that, "switch". just a joke.
I have a Class D integrated amp. I compared it to a $10k pre and power amp combo. Power amp is class AB. I also owned this combo. My lowly class D integrated, at one-third the price, humbled that $10k plus amplification. No, I'm not saying I have the best in class D, and no, I'm not saying there isn't better $10k combinations of which I compared. I'm just saying I have proof positive that a modestly priced Class D amp can compete with more expensive class A/AB amplification.
Sony launched the CDP-101 in October 1982. Look where we are today with modern DACs--very much improved.
When was the first commercially available D amp introduced? Over the same span of years, we can expect similar progress.
At the same time, just as there are today many vinyl enthusiasts, so then, at that date in the future, there will be many Class A enthusiasts, with companies catering to them.
I have looked over that Technics technology and hope that it may trickle down into more affordable components as right now 20k is a very hard sell to non believers.
It like everything in technology life it will come to the masses. Just look at all the Formula 1 improvements that all come to your family car within a very short time.
Hopefully somebody can make it happen for a lot less dollar!
It will, those same EPC guys who made the GAN transistors for that Technics SE-R1, were also the inventors of the "power mosfet" many years ago. They are the inventors (Formula 1 guys) and they sell their inventions to the big semiconductor manufacturers, who then stamp them out by the thousands, and supply them to the masses.
I was wondering when George would chime in. George thinks he knows what is wrong with class D and he lets us know constantly. However, the tide is already turned as witnessed by the every increasing posts of those that have dumped their class a and class a/b amps in favor or class D. George, please read this review of the brand new $8000 mono blocks from Nuprime and how they compare with all kind of amps. Only the $40,000 CH precision was more informative:
And this is just the beginning. We will soon have amps at even lower price points that are going to surprise everyone. Stay tuned......my amps are soon to be released.
The switching frequency and even what output devices you use are only a small part of the story. Every single thing has to be done correctly or you lose the quality. My amps are using the latest Icepower modules (IceEdge) and switch at 500K......however, with the right massaging, they produce sound that is beyond my own designed class A amps....this is serious sound! Those who have heard the latest Class D know what is really happening. Those critics that have not heard the very latest are simply in the dark.
My amps are using the latest Icepower modules (IceEdge) and switch at 500K......however, with the right massaging, they produce sound that is beyond my own designed class A amps
I see just someone shilling his wares. Massaging 500khz switching frequency will only get you half the way to a happy ending. Try 1.5mhz like Technics did, and you'll finish on a bigger high. Or 3mhz and you be in orbit. It will come soon enough, as I said EPC the makers of Technics SE-R1 GAN transistors are the Formula 1 pioneers of the Class-D world, just like they did with Mosfet transistors many years back, and look how quick they took off, must have made EPC some crazy big royalties, they are inventors that sell their patented inventions to the highest bidder. The forula 1 guys of Class-D.
This morning on the morning show they said electric cars are not going to take off for another 15 years. Where are we at with class D right now? Everyone keeps saying that the future is class D but where is that in the future?
They’ve been saying that since the 1910s- but about 1912 Ford and Edison had an electric that could cruise at 60mph and had a 100 mile range, using Edison’s nickel iron batteries, which had a service life of about 25 years. Imagine what things would look like if Edison’s labratory hadn’t been burnt to the ground 2 weeks after Ford and he made that announcement! See ’Internal Combustion’ by Edwin Black. Class D is very attractive because of energy, just like electric cars. The difference is that we can have Class D although IMO it still has a way to go. @georgehifi
this then allows the low order switching noise output filter to do it’s job completely without leaving any effects and any left over switching noise artifacts within the audio band.
I think you don’t understand how the filter works, based on this statement. The Technics filter does not filter out all the residual, which is what the leftover switching artifact is called. The residual is always a very clean sine wave; the real question is what amplitude does it have? The filter really has nothing to do with ’left over switching noise artifacts’!! What can happen in a class D is the switching noise can radiate into other parts of the circuit where it can be rectified and amplified. Again, the filter has nothing to do with this- the noise problem is dealt with through good layout and compact (surface mount) design. @minorl
In car audio it was really the only way to go to get the power output needed. you can’t do it from 12 VDC.
Just a correction: My Denon car stereo amp that I had in my Bronco (RIP) made 150 watts per channel and was an AB amplifier. It employed an inverter to boost the DC voltage. Inverters were used back in the old days when car radios had tubes in them, although they were a different technology, using something called a ’vibrator’ which was essentially a high speed relay that reversed the DC to the power transformer about 50 times per second. @kosst_amojan
It’s also nice not having a massive pile of filters trying to turn garbage into a signal again.
This statement is problematic. If you listen to digital, something similar is happening there (and of course its an objection that analog guys often raise). And the Berning amplifiers employ a filter at their output too- and those amps are class A or AB despite a switching component that has to be filtered- and it gets very good reviews!
The filter on a class D is usually quite simple; there is not a ’massive pile’. If you raise the switching frequency sufficiently, the inductance of the speaker itself can be sufficient to attenuate the residual. The filter is there mostly to prevent the speaker cable from acting as an antenna for the switching frequency. Because the filter is usually set somewhere well below the switching frequency, the residual is a simple low distortion sine wave which won’t cause interference to higher frequency (radio) services.
the noise problem is dealt with through good layout and compact (surface mount) design.
Really then no one one yet has been able to rid of this, and they are mightier minds than you. Only Technics has so far been able to reduce it greatly, with double the switching frequency speed and then the normal output low order filtering of it.
As you can see in this simulated 1khz square wave shot, the ideal is the "grey" square wave no ringing. The "red" is the what’s available today and it hasn’t changed, the last photo below is whats representative of today’s class-D’s The Technics is the "blue" uses the GaN transistors, very fast quickly settling and reduced ringing, much closer to resembling the ideal grey square wave.
https://ibb.co/87Kh2mV
And now bench tests of Stereophile, use a special very low power high order -100db line filter between amps output and test gear input. (Audio Precision’s auxiliary AUX-0025 passive low-pass filter), Which eliminates noise between amp’s output and test gear input so reader can’t see it anymore.
The esthetic beauty of tubes is appealing to many (and deemed silly to others), and with modern technological improvements accumulated over a century or so of refinement, tube amps are currently good enough to still be considered among the best sounding music reproduction devices out there. I think it's based on the relative simplicity of their designs along with the linearity of tubes relative to other things, and hats off to Class D designers for making efficient and explosively powerful amps that work well and fit into small spaces (like live sound speakers). However, for many of us tubes are simply more fun...I was floored when I first heard the little single ended amp I now use, and felt that everything I knew was sort of wrong. Dynamic range from 12wpc? Yep...matched with efficient speakers of course. Noise? No problemo...Heat? Only 4 tubes there sparky, and they last a long time. I can live with the thousands of SS A/B and D watts I use mixing live shows, and my 10 or 12 tube watts in my hifi rig...as long as tubes are available.
Tubes are way cool and if not for deciding to try the latest and greatest new amp technology (Class D) first I might well have headed down the tube amp path several years back but hasn’t happened and I have little interest these days. Technology does in fact keep advancing and you don’t know what is possible until you try it so older technologies face more challenges these days than before perhaps. Looks do count though and tube amps still look way the coolest by far.
The Technics is the "blue" uses the GaN transistors, very fast quickly settling and reduced ringing, much closer to resembling the ideal grey square wave. https://ibb.co/87Kh2mV
And now bench tests of Stereophile, use a special very low power high order -100db line filter between amps output and test gear input. (Audio Precision’s auxiliary AUX-0025 passive low-pass filter), Which eliminates noise between amp’s output and test gear input so reader can’t see it anymore.
Hm. Seems to make a difference about what you might know about what you are looking at.
In the first link above, no frequency is specified! Its clearly marketing and nothing else. In the second set of links, what we are seeing appears to be the residual imposed on the square wave. Nothing unexpected. Since the filter is low power, so is the square wave depicted. These links IOW really don’t show anything other than that at the output of a class D amp, there is a residual sine wave as I mentioned before.
Really then no one one yet has been able to rid of this, and they are mightier minds than you. Only Technics has so far been able to reduce it greatly, with double the switching frequency speed and then the normal output low order filtering of it.
:) That’s funny! The reason the Technics has lower residual is because for a given filter turnover frequency (probably about 80KHz), the higher the switching frequency the lower the residual. No mystery- just faster switching times. IOW, what you referred to in the Stereophile links as the ’noise’ is a red herring- its not at all what you **seem** to think you’re talking about.
600khz v 1.5mhz switching frequency The higher the switching frequency the higher the low order output filter can be set, so by the time the residual reaches 20khz what’s left with the 1.5mhz is down nearly 3 lower in amplitude and has less phase shift in the audio band than that of normal 600khz switching frequency. Blind Freddy can see that.
George, the residual **is** the switching frequency. So this bit
so by the time the residual reaches 20khz what’s left with the 1.5mhz is
down nearly 3 lower in amplitude and has less phase shift in the audio
band than that of normal 600khz switching frequency.
doesn't make sense as written. I think what you are trying to say is that with a switching frequency 3x higher, the residual will be reduced (given that the filter in question is the same whether the amp is switching at 600KHz or 1.5MHz). Its helpful to express this in db; assuming a 6db slope the residual will be down an additional 9 or so db. Which is nice!
The 20KHz part has nothing to do with it. Whether you measure at 20KHz as opposed to 20Hz (if you change the timebase on the oscilloscope if you are observing either frequency as a test signal) the residual will be the same amplitude.
Stevecham, and yet Paul McGowan of PS Audio maintains that the Stellar is no match for the BHK, or Class A and AB in general. He produces them mostly because of customer demand.
PS Audio is using older IcePower technology modules (completely stock).....not the latest IceEdge. Because of this they have to add a buffer to color the sound to make it more acceptable. The output wires run to binding posts that are two inches long and have push on connectors on them......very not tweak. The IceEdge modules are far better sounding and with tweaks they sound amazing. Yes, PS Audio is behind on this one. I will be A/Bing my super tweaked dual mono IceEdge based amps with the BHK. We shall see what we get.
ricevs43 you said "George thinks he knows what is wrong with class D and he lets us know constantly" That does not mean he isn't a fan (if it's the same George) .
He reviewed a Nord class D with a Hattor passive pre, which I had just purchased to go with my then Emerald Physics 100.2SE monos (prior to that I had 2 generations of W4S amps). He pointed out these were an impedance mismatch. He suggested the Nord as they matched, but Im in USA and they come from EU and required 2-3 weeks build time, then ship. I sold the EPs and got a Audio Alchemy DPA -1 (class D hybrid), apparently also a impedance mismatch, about that time I came across a deal for a Audio Alchemy DDP-1 (DAC/Pre) and am EXTREMELY happy.
After the purchase I found a March of 2016 TAS review of the pair, comparing them to the uber expensive Soulution amp/pre (both of same designer; Peter Madnick. These beauties MSRP @ $1995 I am told recently, that Peter sold to Elac who will be redesigning to a bigger chassis
"You and Ralph both, then we can have a clam bake. And you two can have it out."
And this is what happens when the so called expert has no technical counter argument and resorts to nonsense or insulting. Happens every time with this poster.
FYI, Class D is NOT digital, it is analog all the way through. There are no zeros and ones.
Class D is analog, but the output is switched, so IMHO it's arguable to say there are no zeroes and one's. There are, in the output stage. However, the control of that switching state is purely analog.
There are also some amps like the latest Technics SE-R1, which are true digital amplifiers in that they convert everything from Analog to Digital, allow for phase and amplitude correction in the digital domain, and then produce an output based on a PWM output stage.
fleschler626 posts12-13-2018 11:31am georgehifi is the poster who has no technical counter argument.
That’s very rich coming from a "fuser", water off a ducks back coming from the likes of you.
" I have both Black and Blue fuses and prefer the blue overall. It was easy to tell which fuses were stock as the difference is so great The fuse change was especially easy with the Blue fuse sounding better immediately versus the 72 hour break-in period for the Black. Get the Blue fuse and enjoy better music without the wait. The SR Blue fuse sounded great right away while the SR Black took 72 long hours to achieve it’s great sound. I’m so happy to pay only $20 more for a ready to use fuse."
So, if you believe "audiophile" fuses sound different and better than stock fuses, you are crazy? So you attack someone because they have a different belief than you? George, you are treading on thin ice here. You may get yourself banned for this kind of unkindness.
I heard the distortions of fuses back in the mid 80s. This is not new. The latest fuses make a serious beneficial difference in a serious audio system. Anyone can hear the difference. Your class D or any other class of amp will sound better with Synergistic or Audio Magic Fuses.
However, this is not a thread about fuses, but Class D amps and their future.
I don't believe any Class D amp today is state of the art. Some of them are fantastic and better than other amps within their price range but we have lots to go in this dept. Just like digital it is a new medium so will take a while to mature. But in the last five years they have leaped from meh to OMG. However, even the coils and caps on the output of Class D amps imprint a sound. Most all coils used are just ordinary copper......If you make the coils from OCC wire and cryo them they will sound better. No one has done this. The caps in the output filters need to be world class or veiling will happen. These same caps on the output need their outside foil oriented to ground. No one is doing this....except me. The game in never ending. What is really cool about Class D is that you can get an incredible sounding amp right now for way less than those 100 lb. class A monsters, so you can spend more money on something else in you system that makes more difference (including better fuses in all your gear).
I don’t take **** from someone who has posted what he said about mains fuses seriously, and if you want to keep any cred at all, I advise you that you shouldn’t either. But then some remarks you’ve made about mains fuses, are dodgy to say the least, but then maybe you want to play both sides of the fence for a reason.
You are acting more hysterical by the minute. How am I playing both sides of what fence? I clearly state that audiophile fuses are a good thing. No two sides here. The first two questions above were for you! Maybe you cannot read or comprehend well? I will not longer respond to you, George. There can be no conversation worthwhile with someone who only listens to himself. George, I wish you well, but to have friends you must play nice. A world with love and peace is what I create.....more and more. What do you want to create? Bless you, and may you find the higher love and light! Love yourself and everyone. We are all holy and beautiful....every single one of us.
Who in gods name would want a "snake oiler" as a friend.
you must play nice
Why play nice with the "snake oil" pushers here, they just have their hands in the gullible's pockets, they are con men and need to be exposed not pandered to.
There's too much of this snake oil BS creeping into hiend audio because of the money to be made (eg $250 for a 20c fuse) and then being told it's directional and also needs to break-in for 200hrs.!!! It just drags audio down, just show some of this "snake oil" stuff to any electronic genius who has nothing to do with audio, and he will laugh in your face.
Why is it that electronics designers like George and others who post are so far behind the rest of the audio world? Are they afraid their designs might not be perfect? Are they afraid they might have been wrong all this time? They don’t like eating crow? What we have here , gentle readers, is a remarkable stubbornness and contemptuousness on the part of some electronics manufacturers to acknowledge the superiority of aftermarket fuses, even in the face of overwhelming evidence. But also, belittling fuse manufacturers and customers. What evidence? You know, like 80,000 fancy fuses sold. Hel-loo! Wake up and smell the coffee, guys! ☕️
george, you would have had more credibility arguing against people trying to make a buck, pushers, etc., if you stopped pushing your passive preamps every time the topic of preamps comes up. Going way off topic here, sorry.
A good tube preamp with tubes to taste and coupled with a great SS power amplifier is IMHO the best thing since sliced bread. It is like having your cake and eating it. Great SS amplifiers come in various topologies - overall design being most important - but I seem to like MOSFET output stages most and Class A.
As far as fuses go....well I stay clear of such garbage boat anchor components - anything that changes audibly due to a change of a fuse is obviously a hopeless design to begin with. Good luck to those who own such ridiculously finicky pieces of equipment.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.
