Saturnus,
seriously, with all due respect when talking about sound quality, but please I may have missed it, at which point did Class D Amps exceed the performance specs of a decent Class AB other than efficiency and perhaps power ? What is the general magnitude of THD of a Class D at lets say 20kHz at rated power ? Can you find a spec on that to backup your claim that Class D is far exceeds the sound quality of a Class AB ?
Let me guess, either you are almost deaf or you have a great selection of MP3's you use to judge about amplifier sound quality.
Actually, yes, I was recently and it sounded horrible with all the echos, feedbacks and audience noise.
But if this is how this should sound like, then I missing out a lot and there must be something seriously wrong with my CD's. Did you manage to find a Class D THD spec. far exceeding that of a decent Class AB amp ?
Cheers
0.005-0.008% THD+N is in the realm of 'low enough' in my book. THD hardly measures sound quality anyway ...
Otherwise, how does this look to you?: Ncore Announcement
And anyway - there are exquisite sounding Class D amplifiers out there, and that's that!
My old, now scraped Son of Zen amp had terrible THD+N rating as do most tube amps, at least those I've had, so I complete agree. No one that has an interest in music cares about distortion figures but how the distortion sounds. In essence all instruments distorts sound anyways, otherwise they'd just be sine wave generators. And our ears depend on distortion to in order to localize sound. Speakers also distort far more than a typical amp so it hardly matter much an amp distorts, it's more a question of how it distorts.
I was told by many experts that a tube amp distorts earlier but in a harmonic way while a Transistor designed amp in Class A/B principle distorts later but it leads then into a terrible result ...
In a very confident and a trustfully german high end magazine I noticed very often that the testers prefer and handle tube amps like their own childs.
We should not forget that the margins of a class A/B transistor amp are much more than of a tube amp (preconditioned it is hand made in europe). In automation way Transistor amps are much more cheaper to produce.
I can imagine that these "magic" in sound is delivered best by tube amps but I am honestly not the friend of them: not easy to handle, higher current consumption for some watts, bass could be a bit sponge. I think a Tripath
is the way to go. I am very pleased with some of them.
kristleifur,
interesting paper you had referred to, I have to admit, I was not aware of that, the specs given in this paper, if true, are getting close to if not surpassing Class AB performance. Seems it is time for me to take Class D for a serious test drive...
Class D vs Class A and B
I design and build both types of amplifiers. Class D in terms of efficiency cannot be beat. Raw specs the class B route is the best. I use as my reference my highly modified McIntosh MI350 mono blocks.
No amplifier I have designed can approach the performance of these McIntosh amplifiers. I do direct double blind A-B listening tests and the Macs always come out on top. Yes they are huge at 125 pounds each, 19" rack mount and they suck huge amounts of power from the wall socket.
For our mobile amplifiers we stand by class D. Class B in a car cannot compete. The issue of limited bandwidth is not an issue in the car. Our class Ds are flat to 35KHz with 2,4, and 8 ohm speakers.
Steve Mantz
Zed Audio Corp.
I design and build both types of amplifiers. Class D in terms of efficiency cannot be beat. Raw specs the class B route is the best. I use as my reference my highly modified McIntosh MI350 mono blocks.
No amplifier I have designed can approach the performance of these McIntosh amplifiers. I do direct double blind A-B listening tests and the Macs always come out on top. Yes they are huge at 125 pounds each, 19" rack mount and they suck huge amounts of power from the wall socket.
For our mobile amplifiers we stand by class D. Class B in a car cannot compete. The issue of limited bandwidth is not an issue in the car. Our class Ds are flat to 35KHz with 2,4, and 8 ohm speakers.
Steve Mantz
Zed Audio Corp.
Amused by this Blog
I am totally amused by this entire blog. High Fidelity by definition means very close to the original program material. Class D amplifiers cannot and will never be able to compete with a Class A or AB amplifier with regard to sound fidelity, period. There are many who dispute this, but then again, most people cannot differentiate between good sound and mediocre sound quality anyway. It takes a "real" musical artist or someone close to an audiophile to actually understand the difference they are hearing. There are many more details to specifications than the general S/N ratio or THD. How about Square Wave Tilt, or Transient Intermodulation Distortion? What about the artifacts generated by class D amplifiers that don't even exist with a Class A or AB amplifier. These do exist and can be heard.
The big difference here is music content. There is basically no quality recordings created today, most being distorted computer generated sounds and of course my favorite, autotune. High fidelity is not needed for this program source because the source itself is far from high fidelity anyway. Therefore, class D audio is fine for this.
So, if you want it to sound really "nice" in your car or home, go with a good class AB amplifier (one with transistor outputs, not amplifier ICs). If you want to show off how really loud your equipment is so the entire neighborhood knows you are around, class D is the only way to go. But if you can't even tell the difference, go with what you like and subscribe to 16 kb/s Serius-XM satellite radio streams as well.
Signed,
A very seasoned & experienced analog /digital audio electronics design engineer.
I am totally amused by this entire blog. High Fidelity by definition means very close to the original program material. Class D amplifiers cannot and will never be able to compete with a Class A or AB amplifier with regard to sound fidelity, period. There are many who dispute this, but then again, most people cannot differentiate between good sound and mediocre sound quality anyway. It takes a "real" musical artist or someone close to an audiophile to actually understand the difference they are hearing. There are many more details to specifications than the general S/N ratio or THD. How about Square Wave Tilt, or Transient Intermodulation Distortion? What about the artifacts generated by class D amplifiers that don't even exist with a Class A or AB amplifier. These do exist and can be heard.
The big difference here is music content. There is basically no quality recordings created today, most being distorted computer generated sounds and of course my favorite, autotune. High fidelity is not needed for this program source because the source itself is far from high fidelity anyway. Therefore, class D audio is fine for this.
So, if you want it to sound really "nice" in your car or home, go with a good class AB amplifier (one with transistor outputs, not amplifier ICs). If you want to show off how really loud your equipment is so the entire neighborhood knows you are around, class D is the only way to go. But if you can't even tell the difference, go with what you like and subscribe to 16 kb/s Serius-XM satellite radio streams as well.
Signed,
A very seasoned & experienced analog /digital audio electronics design engineer.
I think both class A/AB and class D have reached the point of acoustic transparency at their respective best, with best being measured numerically. I believe if you ABX compared the best class D amp on the planet to the best class A/AB amp on the planet, very few if any people would be able to distinguish which amp is which.
But personally, I've given up trying to chase down the best sounding audio equipment. I do try to avoid buying garbage, but my opinion of "good enough" has definitely come down.
I did that by building my "headphone DAC", using the best parts I could find and the best design I could possibly create. I benched it on Audio Precision gear, and it measured absolutely wonderfully. I bought a good set of Grados and started listening to a lot of different music. I started listening "into" music a bit more - paying attention to different instruments, recording quality, etc... I found it interesting for a while, and started to appreciate good audio engineering. But then I got bored with it.
Nowadays my best enjoyment of music comes from plain 'ol variety. One of my friends is a vinyl addict - I pop over to his house, and he'll show me an album he just bought that I've never heard of before, or perhaps heard about but never really listened to. We'll throw it on the turntable, and sit on the couch with a couple of good beer.
His sound system is a cheap Sony record player, an old Technics amp, and PSB speakers. Far from high end. But it's fine.
But personally, I've given up trying to chase down the best sounding audio equipment. I do try to avoid buying garbage, but my opinion of "good enough" has definitely come down.
I did that by building my "headphone DAC", using the best parts I could find and the best design I could possibly create. I benched it on Audio Precision gear, and it measured absolutely wonderfully. I bought a good set of Grados and started listening to a lot of different music. I started listening "into" music a bit more - paying attention to different instruments, recording quality, etc... I found it interesting for a while, and started to appreciate good audio engineering. But then I got bored with it.
Nowadays my best enjoyment of music comes from plain 'ol variety. One of my friends is a vinyl addict - I pop over to his house, and he'll show me an album he just bought that I've never heard of before, or perhaps heard about but never really listened to. We'll throw it on the turntable, and sit on the couch with a couple of good beer.
His sound system is a cheap Sony record player, an old Technics amp, and PSB speakers. Far from high end. But it's fine.
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see theres your problem, the grados will have only shown you really high midrange quality
hehe i like to have both styles of reproduction available to me, i suppose my tastes do lean more towards the analytical (I use jh13 custom in ears or HD600), particularly for producing music. I also enjoy listening to my older tunes on less than perfect gear with my denons for nostalgia's sake, nothing wrong with that.
agreed the 2 seem to have finally collided and are similar enough to call equal, with the only arguments being intellectual. I do still prefer Class A or AB, but TBH i'm yet to hear the latest generation of Class D and i'm not done tweaking yet
Having only just heard of the concept of audiophile class D, I have done quite a bit of searching, and I think I understand why some people like them.
Some of the modules and designs have surprisingly good specifications, close enough to typical AB performance, that the distortion would not be perceived. On the other hand, the damping factors are unbelieveable, and I am not sure that class AB designs could ever match them.
The point is that these modules will have exception control of the cones, and it is possible that the overall distortion resulting from class D driving a speaker could be lower than a class AB driving the same speaker, even though the class AB on its own may have much better performance in terms of distortion.
This makes them worthy for more study as audiophile options. Class AB have basically reached the peak of their evolution, while class D still has a long way to go.
On the negative side, I am afraid that class D are the way of the future. I expect that in 10 years class AB will not be available in anything but the most expensive commercial equipment. For manufacturers, price is everything, and it is also possible that governments could get involved as part of the push to go green. If that happens, the market will be overrun by low quality cheap class D equipment.
Some of the modules and designs have surprisingly good specifications, close enough to typical AB performance, that the distortion would not be perceived. On the other hand, the damping factors are unbelieveable, and I am not sure that class AB designs could ever match them.
The point is that these modules will have exception control of the cones, and it is possible that the overall distortion resulting from class D driving a speaker could be lower than a class AB driving the same speaker, even though the class AB on its own may have much better performance in terms of distortion.
This makes them worthy for more study as audiophile options. Class AB have basically reached the peak of their evolution, while class D still has a long way to go.
On the negative side, I am afraid that class D are the way of the future. I expect that in 10 years class AB will not be available in anything but the most expensive commercial equipment. For manufacturers, price is everything, and it is also possible that governments could get involved as part of the push to go green. If that happens, the market will be overrun by low quality cheap class D equipment.
Maybe having only 'heard the concept' of class d, one can now actually move on to actually 'hearing' them.
I have heard one used as the amp for a bass guitar. It was absolutely superb. Although this is still a long way from a full hifi situation, I think this is a really good application for them.
I will make one as soon as Silicon Chip publishes a design (yes, I have asked), or using modules if this takes too long. I really can't lose, as I will turn them into guitar or subwoofer amps if I am not happy with them.
I will make one as soon as Silicon Chip publishes a design (yes, I have asked), or using modules if this takes too long. I really can't lose, as I will turn them into guitar or subwoofer amps if I am not happy with them.
The first harmonic is 40 kHz, so why would that matter at all?
What's so important about very high DF?
All it means is a low output impedance, and it quickly loses significance when you consider that this is in series with a voice coil of several ohms.
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Absolute nonsense I have yet to hear a Class D amplifier that is listenable. However I have not heard the Devialet Premier but at £12K it does not interest me.
"Let me guess, either you are almost deaf or you have a great selection of MP3's you use to judge about amplifier sound quality."
A well-encoded Mp3 can not be distinguished from an uncompressed WAV-file from 160 kBit/s up (basically even at 128kBit). Just rip a CD track 1:1 into .wav, make an Mp3 using a good encoder in VBR 160 or better, then open and convert/save this .mp3 back to uncompressed .wav, 16 Bit, 44.1kHz (CoolEdit). Burn the new .wav and the original .wav to CD - then tell someone to play both .wav's on your high end stereo in an order you don't know. Then try to tell which one is which one! Good Luck!
A well-encoded Mp3 can not be distinguished from an uncompressed WAV-file from 160 kBit/s up (basically even at 128kBit). Just rip a CD track 1:1 into .wav, make an Mp3 using a good encoder in VBR 160 or better, then open and convert/save this .mp3 back to uncompressed .wav, 16 Bit, 44.1kHz (CoolEdit). Burn the new .wav and the original .wav to CD - then tell someone to play both .wav's on your high end stereo in an order you don't know. Then try to tell which one is which one! Good Luck!
The difference is not negligible - any person with normal hearing will recognize the MP3 in 10 of 10 testing sessions. You should examine your hearing, seriously. Your writing style reveals a young person, so if there is a problem with your hearing you better treat it while you are young, don't let it become worse with years.
I have a friend who used to spend large amounts of money on hi-fi gear and he was never satisfied with reproduction of high tones although it seemed OK to me. A visit to an ORL specialist revealed that he hardly hears anything above 3kHz...
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