I confess it's one of my pet peeves that indeed that still is the case. And it's not just the general public, but hordes of folks who ought to know better, especially marketing types.
Indeed, Harman had what I like to call "digital-penis" envy for years, and at one point when they managed to put a offline power supply, based on a Power Integrations chip, into a little powered speaker system, it was proclaimed to be a "Digital Power Supply"
When, much later, Gina Harman decided that Harman Consumer had to have "digital" amps in the latest Harman-Kardon receivers, they listened to the siren song from D2 Audio and filled three-quarters of the space inside of a big receiver enclosure with D2 amps and (one whole half) a power supply. The remaining one-quarter was devoted to functions that were really needed
The performance was so mediocre that they intentionally mistated and watered-down the specs of the conventional class AB amp-powered h/k receivers that were still being offered!
But hey. They were digital. Therefore better, right?
In the meantime, TI wanted very much to displace D2 from that space, and I was approached to design a hybrid (discretes and integrated circuits) amplifier that would meet the power demands of Harman-Kardon (200W into 8) while the acquired group in Denmark (previously known as TacT) was still working on higher-voltage processes to fill the needs with integrated parts. They wanted my services too cheap so we never did anything. It was probably as well, as it was already a delicate matter to make full disclosure to Harman of what I might be doing, since the latter was at that time my principal client.
And life goes on.
then post up Square wave responses of Another class-d amp, i posted what i could find from a highly rated amp, have no dog in this fight , so there's no motive ....
Class D amps have been getting much better on the traditional THD measurements - probably now much better than the 'low feedback class A' type of amp. But still don't sound as good as the latter - just another sign that we're still in need of a better metric for SQ than THD. I reckon that when Class A and Class D are compared for noise modulation it will be clear which is superior
@mr_push_pull
True, I didn't like the shut in atmosphere which is not there when played on conventional class AB power amps, but this is related only to those I have heard. And I have not heard many, I was clear on that.
Class D is a new technology, and as every such technology, it takes time for designers to really get into the matter down to fine nuances. Remember, it took transistors like 20 years to become really serious contenders in the sound quality arena (in general, I mean).
Class D may not require quite all of another 20 years, of course, these days we do have the Internet, thus information dissemination is far faster than it was in those days. But it will need time.
The issue of digital, as Brad pointed out, can be made very relative. I too have heard switch mode power supplies being referred to as "digital". If we are to blame anyone, we should blame the sales departments of large companies, they are usually the ones who launch acronyms and inaccuracies simply because it suits them, they think it boosts sales. Not to even mention the really zealous types who'll do anything for sales.
True, I didn't like the shut in atmosphere which is not there when played on conventional class AB power amps, but this is related only to those I have heard. And I have not heard many, I was clear on that.
Class D is a new technology, and as every such technology, it takes time for designers to really get into the matter down to fine nuances. Remember, it took transistors like 20 years to become really serious contenders in the sound quality arena (in general, I mean).
Class D may not require quite all of another 20 years, of course, these days we do have the Internet, thus information dissemination is far faster than it was in those days. But it will need time.
The issue of digital, as Brad pointed out, can be made very relative. I too have heard switch mode power supplies being referred to as "digital". If we are to blame anyone, we should blame the sales departments of large companies, they are usually the ones who launch acronyms and inaccuracies simply because it suits them, they think it boosts sales. Not to even mention the really zealous types who'll do anything for sales.
There is a general problem that most people now believe that 'digital' must be superior to 'analogue'. Even EEs are now taught that. The truth is that the appropriate technology (whichever it is) will be superior for a particular appllication, in some cases provided that you don't exploit advantages too much.
For example, EEs are taught that digital radio is more robust than analogue. But there is an unspoken caveat: assuming similar power and bandwidth. In reality digital radio uses lower power and wider bandwidth (more noise), so the net result is that digital radio tends to be less reliable then analogue. By exploiting a potential advantage that advantage is nullified. (I am not trying to divert the thread into a discussion about digital radio - just using it as an example).
Somehow we need to get across to people that digital is not necessarily better, so there is less scope for marketeers to misdescribe analogue switching systems such as Class D. Digital means numbers, not switching.
For example, EEs are taught that digital radio is more robust than analogue. But there is an unspoken caveat: assuming similar power and bandwidth. In reality digital radio uses lower power and wider bandwidth (more noise), so the net result is that digital radio tends to be less reliable then analogue. By exploiting a potential advantage that advantage is nullified. (I am not trying to divert the thread into a discussion about digital radio - just using it as an example).
Somehow we need to get across to people that digital is not necessarily better, so there is less scope for marketeers to misdescribe analogue switching systems such as Class D. Digital means numbers, not switching.
well, from a completely empirical/unscientific stand point, I don't miss the analogue TV a bit. the reception was so dependent on the analogue part of the TV, some were exceptional some were awful. with digital TV the quality is consistent.
Digital means discrete values and since the output transistors of a classD amp are either on or of, you could rightfully call them digital. However, I agree that it may lead to confusion to do so.
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Consistent if it works at all, horrible or nonexistent in the presence of insuperably high and shifting multipath or simply way-too-low signal level. Overall, perceived as an advance for the majority of users.
In this connection: I was approached to design an antenna for the new transmission standard. I know little about antennas, but I thought about the problem and concluded that the issue would usually be multipath, and some sort of active diversity reception system might address it.
A patent search revealed that I was a few years late
never been to the US but my friends told me that at least in the major cities good ready-made food is impossible to find so I see where you're going.
on another note, I can't find any fault with the image quality on digital. if only for the benefit of HD and it's enough for me.
this is absolutely false.
red cars are faster, same type of logic.
There's discrete time and there's discrete amplitude. What's usually called "digital" is both, but Class D is only discrete amplitude.
The details are crucial: timing, amplitude, rise and fall times, dead time. Shift in on resistance when they are on from self-heating. There's even noise in the creation and annihilation of the conducting channel (in DMOS), something I've yet to see addressed (!) except in ultra-low-power switching applications (years back, for image sensors, Brugler and Jespers, I'll find the ref, and even they don't discuss the statistics).
The symbol domain requires only that we be able to unambiguously process and recover the symbols. Nothing per se is said about when and how. We could do the processing with different colors of pigeons in principle.
spot on. if one wants them to be digital, fine, not much to do there but that doesn't make it so. by the same logic I could say that as long as everything is made of discrete particles, including humans, even analog is digital.
what other point of view is there? I pay the same, I get HD (no point arguing about the improvement, really) and the reception is definitely better. yes, when I bring my class D amp (LOL, here's a disadvantage) which is also powered by a SMPS close the TV cable, instead of seeing superimposed lines or whatever type of image distortion, I get pixelated picture for a few seconds and soon none at all. but if I don't (and I don't) there's no comparison.
I honestly don't see the point of this by now heated discussion is it digital or not. Whatever you conclude, and whatever it really is, in the eye of the public (i.e. 99.99% of the buyers) it is digital - period.
And is digital better than analog? You betcha, big guns spend literally billions of ad dollars on creating a public view that digital is the best yet, bar none. It started in the early 80ies with the advent of the CD format - remember the argument: high resolution, no crackle, no pop, eternal media which does not get ploughed by some wild cartridge, etc?
DAB I cannot comment, never really heard one, but was told by friends from the UK that BBC use an MP3 format? Tell me that, and it's dead in the water for me. I'll just refresh my auncient reVox B760 digita tuner, thank you. It's going to cost me, but on two local stations, one of which is my favorite, at times I can't tell if it's the tuner or a CD.
On the fmtunerinfo.com site, it is rated as the 8th best tuner ever made. By comparison, Day Sequerra (THE legend of the 70ies and 80ies) is on the 56th place, and the current fav Magnum Dynalab's first offering is on the 20th place ( Tuner Information Center - Shootouts ).
Lastly, digital IS way better than any analog I've ever seenm just like my neighbor mr_push_pull. We can discuss why this is to, and probably the fact that it eliminates a local antenna in a 2 million strong city, on hilly ground, would be a prime factor. Whatever, Fox Crime/Life/Movies, and many other stations, come across almost exactly as well as if I were using a DVD. Add to this the HD option, and any comparison with analog becomes ridiculous. A bit like comparing a plain vanilla, white VW Golf with a red Porsche.
And is digital better than analog? You betcha, big guns spend literally billions of ad dollars on creating a public view that digital is the best yet, bar none. It started in the early 80ies with the advent of the CD format - remember the argument: high resolution, no crackle, no pop, eternal media which does not get ploughed by some wild cartridge, etc?
DAB I cannot comment, never really heard one, but was told by friends from the UK that BBC use an MP3 format? Tell me that, and it's dead in the water for me. I'll just refresh my auncient reVox B760 digita tuner, thank you. It's going to cost me, but on two local stations, one of which is my favorite, at times I can't tell if it's the tuner or a CD.
On the fmtunerinfo.com site, it is rated as the 8th best tuner ever made. By comparison, Day Sequerra (THE legend of the 70ies and 80ies) is on the 56th place, and the current fav Magnum Dynalab's first offering is on the 20th place ( Tuner Information Center - Shootouts ).
Lastly, digital IS way better than any analog I've ever seenm just like my neighbor mr_push_pull. We can discuss why this is to, and probably the fact that it eliminates a local antenna in a 2 million strong city, on hilly ground, would be a prime factor. Whatever, Fox Crime/Life/Movies, and many other stations, come across almost exactly as well as if I were using a DVD. Add to this the HD option, and any comparison with analog becomes ridiculous. A bit like comparing a plain vanilla, white VW Golf with a red Porsche.
My point is not that digital can't be better, but that it is not necessarily better so it should not be assumed to be better simply because it is digital. Some jobs are better done by digital; other jobs are better done by analogue.mr_push_pull said:
No. Digital means something representing the data/signal of interest by discrete values. In Class D the signal is represented by mark:space ratio which is an analogue representation. Similarly, an SMPS is not digital. Neither is a Class E RF PA.vacuphile said:
Although digital may imply switching, switching does not imply digital.
Worse than that, DAB uses MP2.dvv said:
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You jest, Sir Knight?
Seriously, DF96? How? Why? For almost a century, Beeb has been a paragon of technical excellence, how could they sink that low? Too many child abuse scandals?
this is what I don't get and I have the hunch that you know exactly what I'm talking about but pretend otherwise.
the differentiation between digital and analog is not a matter of wording. you said that they're digital and then added that what's what the public thinks of them. I never had the impression that this is a thread for the general public. in my book, the general public doesn't have the slightest idea what "sound stage width" means, they're happy as long as there's some sound coming out of the speakers and they can tell guitar from trombone.
anyway, I'll drop it, there's obviously nothing good coming out of this.
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