jacco vermeulen said:
Do they take MasterCard? Where's the order form?
I always say - it's recreation. You could go for a drive in the country, you could hop on a plane for a vacation, you could listen to your class A amp, or you perhaps could sit at home in the cold with the lights off. However you choose to spend your time/money/energy is up to you. I choose class A 'cause me likes
Netlist said:Bad badman.
I really think Brian's question has merit and not only from an energy efficiency point of view.
/Hugo
BrianEno said:
Hm. Seems to me I asked a question and stated an impression, no accusations.... I'm not one to curtail legitimate questions, but your phrasing was pretty negative on class A- and it sounds as if your 'question' (which contained quite a few statements) operates on the presumption of Class A as archaic technology.
Short version: it read to me as follows:
"Class A is old. Everyone else in the industry has moved on. Why does Pass continue making products with outdated technology?"
Hugo, not exactly seeing what I did or said that warrants a wagging finger....
FWIW I don't use and haven't built any Pass gear (or pass style), and I use a variety of amps in my various playback chains (office, bedroom, 'big rig') from class D to SE OTL, so I'm not here to call Nelson a "God" (Though I do respect him from what I know)
Perhaps if you had kept the question shorter there'd be less motivation read into it- negative comparisons with the more 'modern' companies, etc, really bias your post towards negativity. This might have worked better:
"With most designs moving to more efficient topologies, why does Pass stay with Class A? Nelson even said "blahblahblah" about it."
Moderate my tone? Euphemism for shut up.GRollins said:
My question is valid and legitimate. This is supposed to be a Forum like in Webster definition: "a public meeting place for open discussion". You remark about the supremacy of Class A is rather absolute. Mother Nature (you dragged her in!) would not prefer a solution that wastes so much resources for achieving a certain goal. As in the Origin of Species from Charles D. those designs will be phased out. I had several Class A amps and they didn't sound good just because they were biased for that point of operation. It's just a parameter of a total conceptual structure. But it has severe consequences for the construction of the amplifier and it's environment. Maybe a valid answer could be that there's a solid marketdemand in this niche or the designer balances the pro's and contra's and concludes it's all worth it.
Just powered up my old ML-3 drawing 180 watts from the line for a max of 6.5 watts Class A power. 'Smooth operator' from Sade is on. Miss the comfy warm illumenated meters from the S/1000.
I think NP himself put it well down:
"Clearly there is a small market segment for audio amplifiers
which consume high power, and that is why they exist. but there
are so few high end audiophiles running big Class A amplifiers
that it is not much of a target for those concerned about the
ecology.
If you are concerned about the environment and still want Class
A, the best thing to do is get some efficient loudspeakers and
buy or build little Class A amplifiers. In fact I recommend that
approach anyway, and between the Zens and First Watt, I
have made it easier for you...."
Quoting P. Klipsch (from memory): "What the world needs is a good 2 W amp".
Class A, B or D, the world could really do with more efficient loudspeakers.
Also, if smallish F3 type amplifiers gives enough power, I cannot see their power consumption as outrageous.
One should see this in some perspective. The world is filled with factories producing all kinds of unneccessary "vampires" that consumes power by themselves - some Watts here, some Watts there. And quite a few of them produced in at factories getting their power from very dirty coal powered power plants.
On perfect voltage sources: Yes, in class A these would use infinite bias current. I once owned ML-2s. Class A into everything between 8 ohms and your big toe. Uneccessary. Only suitable for the old Quad electrostatic. So I sold them. So why mentioning these monsters? Well, they were "perfect" voltage sources (within their limit ;-) ). Is really a perfect voltage source necessary? Electrostatic speakers are best driven by voltage sources. But the common so-called dynamic speaker is really not, because the good old formula F=B*I*L does not mention voltage at all, but rather the current through the voice coil.
An interesting question is then should we really design our amplifiers quite different?
Maybe I de-railed the discussion to some degree. But I think NP has answered for his part, and we should go on discussing something more interresting.
Regds
Rolv-Karsten
"Clearly there is a small market segment for audio amplifiers
which consume high power, and that is why they exist. but there
are so few high end audiophiles running big Class A amplifiers
that it is not much of a target for those concerned about the
ecology.
If you are concerned about the environment and still want Class
A, the best thing to do is get some efficient loudspeakers and
buy or build little Class A amplifiers. In fact I recommend that
approach anyway, and between the Zens and First Watt, I
have made it easier for you...."
Quoting P. Klipsch (from memory): "What the world needs is a good 2 W amp".
Class A, B or D, the world could really do with more efficient loudspeakers.
Also, if smallish F3 type amplifiers gives enough power, I cannot see their power consumption as outrageous.
One should see this in some perspective. The world is filled with factories producing all kinds of unneccessary "vampires" that consumes power by themselves - some Watts here, some Watts there. And quite a few of them produced in at factories getting their power from very dirty coal powered power plants.
On perfect voltage sources: Yes, in class A these would use infinite bias current. I once owned ML-2s. Class A into everything between 8 ohms and your big toe. Uneccessary. Only suitable for the old Quad electrostatic. So I sold them. So why mentioning these monsters? Well, they were "perfect" voltage sources (within their limit ;-) ). Is really a perfect voltage source necessary? Electrostatic speakers are best driven by voltage sources. But the common so-called dynamic speaker is really not, because the good old formula F=B*I*L does not mention voltage at all, but rather the current through the voice coil.
An interesting question is then should we really design our amplifiers quite different?
Maybe I de-railed the discussion to some degree. But I think NP has answered for his part, and we should go on discussing something more interresting.
Regds
Rolv-Karsten
Nelson Pass said:
Sure I prefer a Plasma screen over a LCD one, a Chevy big block V8 over a Volkswagen Lupo engine etc... Maybe in the end it sums up to a significant quantity.
But that's the consumer's point of view. As a designer you could have an other perspective on this matter. It's not a case of moralizing you but rather a case of curiousity why you choose for a solution that consumes (if you like that better then waste) so much resources.
Isn't it the other way around? Because those designs are so expensive that only a few people can afford them?
No it's not gonna save the world if we prohibit Class A amps but that's not the issue here. The issue is of it is still necessary today to waste so much resources for achieving that linearity, that musical goal while other designers claim the same performance (and I don't mean the middle of the road designs) but collagues of you like Jeff Rowland or Thomas Colangelo, Levinson and Krell design teams with designs that are much more efficient. Shouldn't it be designgoal in itself to produce efficient working gear? If you say as a designer it's absolute necessary to achieve the best sounding amplifiying device, at that biasing point, I have no choice then to take that for an answer. If you say it's a marketdriven solution because there's a demand for it then that's a business decision. The truth could be somewhere in the middle.
I don't think there was a demand for your elegant Stasis solution. You just put it on the market as a visionair and your sales boomed as never before I understood. I hope you understand the subtle difference between the two.
Just like you I think because that's were we have to live in.
I have full range Acoustats that do not excel in efficiency but most of the time I stay in the Class A operating area with my ML-3 or Rowland model 8T. So now and then I like to play a louder and then due to the logarithmic operation of my ears I need a lot of power more. Thanks for your reply.
Nelson Pass said:
I think this is a great point. There are tons of low power class A amps, and it does seem that efficient speakers is a better sonic solution than class B amps.
Moreover, at least in the winter, the heat from an amplifier is more efficient than the heat from the heater in your basement as the amp heat is not lost in the pipes on the way up. So, run your amps hard in the winter and turn the heater down a bit
Eeh, not sure, i've got the 400hp Chevy V-8.
According to Hugo's link i need a 280.000W model from NP.
Colangelo's Viola power amp runs in AB2, at 400 watts rms in 8 me thinks it's a hot babe.
Vince,
send me the tag, i'll stick it on the sub. Someone has been smoking cheese again, and it wasn't me this time
According to Hugo's link i need a 280.000W model from NP.
Colangelo's Viola power amp runs in AB2, at 400 watts rms in 8 me thinks it's a hot babe.
Vince,
send me the tag, i'll stick it on the sub. Someone has been smoking cheese again, and it wasn't me this time
BrianEno,
The very title of the thread is a question: 'Why class A?' That's fine as far as it goes (though it's been done to death if you'd only take the time to look at some of the older threads). You assume a hostile stance from the outset, ask a question you don't really want answered, then profess not to understand why no one wants to play your game.
You say that you don't have a technical background. You resist answers that in any way lean towards the technical. Well, duh! If you reject technical explanations for class A, naturally you're going to think that it's an advertising phenomenon.
My advice is simple, although I doubt you'll take it: Unlearn the advertising fluff. Learn some electronics. Learn how bias influences the performance of the gain devices (Nelson recently posted a graph in another thread shows distortion vs. bias--although there's more to it than simple distortion). At that point, you will be in a position to understand why people might choose class A, even though it is relatively inefficient.
You seem to think that there's a magic bullet topology that will let you have it all--something akin to the fabled 100MPG carburetor that has supposedly been suppressed for the last fifty years. Ain't so. Yes, there are distortion canceling schemes, ranging from negative feedback to clever topologies. The funny thing is that if you take a given circuit and crank up the bias...it works better still. It's not that difficult an experiment to perform.
Or if, as I suspect, you simply want to be argumentative, you will find that folks here tend to tire of that sort of behavior rather quickly.
Grey
P.S.: Do you also intend to become a member of websites dedicated to electric toothbrushes? After all, they waste electricity doing something that can be done just as easily by hand. Oh, and electric watches! Don't forget them! Golly, get a stem-winder and save the power. Light bulbs, too...you'll need to become a member of every light bulb site and take a stand for the newer, more efficient florescent bulbs!
No?
I didn't think so.
You're just posturing, and it's annoying. C'mon...show us you're serious. Learn a bit about what you're talking about.
The very title of the thread is a question: 'Why class A?' That's fine as far as it goes (though it's been done to death if you'd only take the time to look at some of the older threads). You assume a hostile stance from the outset, ask a question you don't really want answered, then profess not to understand why no one wants to play your game.
You say that you don't have a technical background. You resist answers that in any way lean towards the technical. Well, duh! If you reject technical explanations for class A, naturally you're going to think that it's an advertising phenomenon.
My advice is simple, although I doubt you'll take it: Unlearn the advertising fluff. Learn some electronics. Learn how bias influences the performance of the gain devices (Nelson recently posted a graph in another thread shows distortion vs. bias--although there's more to it than simple distortion). At that point, you will be in a position to understand why people might choose class A, even though it is relatively inefficient.
You seem to think that there's a magic bullet topology that will let you have it all--something akin to the fabled 100MPG carburetor that has supposedly been suppressed for the last fifty years. Ain't so. Yes, there are distortion canceling schemes, ranging from negative feedback to clever topologies. The funny thing is that if you take a given circuit and crank up the bias...it works better still. It's not that difficult an experiment to perform.
Or if, as I suspect, you simply want to be argumentative, you will find that folks here tend to tire of that sort of behavior rather quickly.
Grey
P.S.: Do you also intend to become a member of websites dedicated to electric toothbrushes? After all, they waste electricity doing something that can be done just as easily by hand. Oh, and electric watches! Don't forget them! Golly, get a stem-winder and save the power. Light bulbs, too...you'll need to become a member of every light bulb site and take a stand for the newer, more efficient florescent bulbs!
No?
I didn't think so.
You're just posturing, and it's annoying. C'mon...show us you're serious. Learn a bit about what you're talking about.
Who's hostile here?
I know the benefits of Class A biasing to keep a transistor in it's lineair operation region away from it's cutof point. I know what crossover distortion is in a complementary design.
But even if I had now tecnical understanding at all I would still be entitled to pose a question why a designer of some of the best audio gear around chooses for a design solution given the context I supplied in my initial posting. If you find that offending so be it. This is a Pass Labs forum that deals about products from Pass and I find it totally appropriate to wonder why the design is what it is. If you start to question my motivation in a earlier posting don't you think I've the right to argument my question.
If you don't like an argument because you know you're just right all the time then there's no cause for a Forum.
Ridiculizing your conversationpartner is not a nice/strong way of changing arguments. I treat you with respect don't I?
Re: Re: Why Class A? Wasting power is something of the past
Thanks I could not envision that it was Levinson cause he started his operation back in 1972.
Lot of people (here) do not want to generalize, must be cautious, I seem to be very popular here with my annoying questions about Class A)) think that you ment Mark Levinson in this photograph.
They all were curly designs, I mean Levinson himself, Colangelo end Glazier.
Nelson Pass said:
Mark Glazier.
Thanks I could not envision that it was Levinson cause he started his operation back in 1972.
Lot of people (here) do not want to generalize, must be cautious, I seem to be very popular here with my annoying questions about Class A)) think that you ment Mark Levinson in this photograph.
They all were curly designs, I mean Levinson himself, Colangelo end Glazier.
BrianEno said:
You either do or do not understand what you wrote...you can't have it both ways. If you do understand, then you've answered your own question and negated your stated purpose in starting this thread. If you don't understand, then you should consider learning a bit of electronics. Your question would then answer itself.
Or, since you seem to prefer it in business/marketing terms: Every product has a natural life span in the market place. Some flop on introduction. Some last for years, perhaps decades. Yet they all reach a point where they're no longer adding enough to the bottom line to make it worth keeping them in the product line. Once the decision is made to terminate the product, a replacement product is needed. That product must be differentiated from its predecessor or it will not sell. So--in the case of audio--a new model appears, sometimes with a new topology, sometimes a 'rediscovery' of some operating class or another. Now, most manufacturers don't really change their product much. If you look at schematics for successive models, the actual guts of the circuit are almost identical. Nelson has a handful of patents and can combine and recombine them in various ways. Not varied enough? Stick in another idea; he is willing to do unconventional things and has more imagination than most. It's more effort than most manufacturers put into their product lines, which is why I spend most of my time in the Pass Labs Forum rather than any of the others. It's simply more interesting.
Why class A?
Indeed.
Because it sounds better, all things being equal. What? You thought class A got its reputation by accident? Or simply because some advertising maven pulled the term "class A" out of a hat? Not so. Had you done your homework, you would have found that class A was the default technology, over a century ago. After all, there weren't any "P" tubes, hence no complementary circuits. Class AB, B, and C (class C is really only of use for radio, but is of historical interest) came along later. If it was all a matter of advertising malarkey, AB and B would be the "latest and greatest." In fact they do have the lion's share of the market, but then the majority of the market is low and mid-fi, isn't it?
Are there people who buy things based on hype and advertising? Obviously. But that's not true for everyone. Some people actually listen, which is where class A comes in. In spite of the fact that it's a dinosaur, both in terms of age and size, class A is still a contender. Why? Because it sounds better.
Take any standard three-stage solid state amp. There's not as much difference between them as as the advertising would have you believe. Set the output stage bias to class B and listen. Then set it to class AB and listen. Then set it to class A and listen. If you can't hear a difference, then go forth and buy the cheapest, most efficient amplifier you can find and be happy. If you can hear a difference, then you have learned something. If it's a project amplifier that you built, then there's no advertising involved. Again, you have learned something. If you conclude that maybe, just maybe, class A does indeed improve the sound, then you reach the point where you can sit down and weigh the sound quality against the consequences for the environment. How you decide that question is up to you.
In the case of the Threshold Stasis amplifiers--incidentally, I own two S-500s--they run class AB. The topology is interesting and produces decent distortion specifications as it stands. That's not to say the amps can't sound better. Increasing the bias does yield some benefit, but the power supply and heat sinking preclude full class A bias. The amps are good, but not world beaters by current standards. They sound hazy. I use them for my subs and woofer panels. They do well in the low frequencies.
I repeat: If you want to actually ask questions and learn, you'll find that you're welcome here. If you persist in your current tone, don't be surprised if you find people avoiding you. Please note that there have already been several posts wherein the posters attempted to answer your question and/or expressed frustration with your attitude. You're not off to a good start.
Grey
'Why class A?'
It is the simplest way to the cleanest possible sound.
'Wasting energy is a thing of the past.'
Not really. Loudspeakers still do it all the time. Many people consider 92dB 1W/1M to be pretty efficient. That's only 1% efficiency, which by my standards is pretty low. Automobiles and incandescent light bulbs are horrible offenders as well. Since I ride a bicycle to work every day and use exclusively fluorescent lighting, I don't feel bad in the least for enjoying music through class A amplifiers. Further, in the winter, any heat not generated by my amplifiers has to be generated by my furnace.
It is the simplest way to the cleanest possible sound.
'Wasting energy is a thing of the past.'
Not really. Loudspeakers still do it all the time. Many people consider 92dB 1W/1M to be pretty efficient. That's only 1% efficiency, which by my standards is pretty low. Automobiles and incandescent light bulbs are horrible offenders as well. Since I ride a bicycle to work every day and use exclusively fluorescent lighting, I don't feel bad in the least for enjoying music through class A amplifiers. Further, in the winter, any heat not generated by my amplifiers has to be generated by my furnace.
I don't get this whole thread. Why all the rumblings about Class A being inefficient? Of course it is, just like all else in this universe. Your car is no more than 10-15% thermally efficient.
Besides, wouldn't a theoretically, fully 100% efficient amp also be reversible, allowing you to input music and get heat and electricity at the output? I would love one of those in my shower.
Where is Carnot when you need him?
Besides, wouldn't a theoretically, fully 100% efficient amp also be reversible, allowing you to input music and get heat and electricity at the output? I would love one of those in my shower.
Where is Carnot when you need him?
BrianEno said:
I didn't think that Pass Labs had reverted to Class A at all. I believe they've been producing Class A amps since inception (were the Alephs the first series?). Class AB also, but always Class A.
Wasting power is another thing. If you're listening to your class-whatever amp, then you're "wasting power", as most of the power is given off as heat (very few current speakers are more than 1% efficient).
If you want to save power, try installing some solar panels; unplug all those "wall-wart" power supplies that are used for telephones/chargers/lights/portable units (as they're always on); turn off one or two lights (one porch light turned off would "pay" for 2 hours of Class A listening).
By the way, are you Brian Eno, or have you just borrowed the moniker?
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