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Audiophiles, generally don't like class D amps!

IPunchCholla

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Some of them think they're scientists, but only to the extent of self aggrandisement, with little more than lip service to what science and this this forum should really be about. Real scientists don't think they already know all there is to know, and sit fat and happy, telling everyone the World is flat because someone else told them it is. Real scientists always doubt their own understanding and have enquiring minds that seek to extend knowledge through a continual process of observation, experimentation and deduction.
No true Scotsmen, eh? Been awhile since I’ve seen that one.
 

MAB

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Some of them think they're scientists, but only to the extent of self aggrandisement, with little more than lip service to what science and this this forum should really be about. Real scientists don't think they already know all there is to know, and sit fat and happy, telling everyone the World is flat because someone else told them it is. Real scientists always doubt their own understanding and have enquiring minds that seek to extend knowledge through an continual process of observation, experimentation and deduction.
Yeah. I just hope everybody reads that AES paper I posted. The paper is a good read, summarizes many studies, and where some glaring experimental error occurred, and where basic statistics were misapplied.

Plus the $30 is well spent in support of science and studies on what does impact audio.
 

SIY

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Some of them think they're scientists, but only to the extent of self aggrandisement, with little more than lip service to what science and this this forum should really be about. Real scientists don't think they already know all there is to know, and sit fat and happy, telling everyone the World is flat because someone else told them it is. Real scientists always doubt their own understanding and have enquiring minds that seek to extend knowledge through an continual process of observation, experimentation and deduction.
And real scientists don't engage in ridiculous strawman arguments.
 

atmasphere

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Interesting, especially this with tube amps and how 2nd and 3rd harmonics mask 7th order harmonic. I buy that.:)
Is it not the even order harmonic that creates the "soft" sound in tube amps? So why are the 3rd order harmonic positive then? Chances are I've got it wrong I should add.:)

The biggest aspect I personally have against tube amps is actually not so much if they color the sound a bit. I can imagine plugging in a tube amp sometimes to get that sound, plus then also get the cozy tube glow as a bonus.:);) The problem, for me, with tube amps is that they are often so damn expensive in relation to the little power they provide.
The 3rd harmonic is treated by the ear much the same as the second, which is to say it adds to the 'warmth' tube amps are known for. But even innocuous things like the 2nd and 3rd harmonics should be kept as low as possible, since distortion obscures detail. The trick is doing this without having the higher orders unmasked in the distortion signature, otherwise the amp might be considered harsh and bright. These days class D amps like Hypex or Purifi have made that pretty well moot.

Tube amplifier power has always been expensive, which is why when tubes were king, there were a lot more horn systems. They are fun to play with, just the same way I enjoy riding my British 3-speed bike; I like the charm of it. But I can go way faster on my road bike.
Except, of course, the vast majority of amps have distortion numbers low enough that none of that special pleading kicks in. AND most solid state amps have 2nd or 3rd as the dominant harmonics anyway- the notion that this is a tube amp thing is a popular one and not particularly correct.
You and I differ in that I think distortion is far more audible and to lower levels than most people think. I stated how in my prior post. No special pleading there, just that's how the human hearing perceptual rules work, which is something very consistent in the entire population.

One of the better amps in terms of the 2nd and 3rd distortion signature (such as it is) is actually the Purifi module. I think a lot of audiophiles don't like it because of its neutrality.
 

SIY

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The 3rd harmonic is treated by the ear much the same as the second, which is to say it adds to the 'warmth' tube amps are known for... I think distortion is far more audible and to lower levels than most people think.
Of course you know the next question- where is the evidence for that? Certainly using Distort software, I can't seem to replicate this (it takes a lot of second and third before I can pick up any difference, "warmth" or otherwise) but I'm a sample of one.
 

atmasphere

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Of course you know the next question- where is the evidence for that? Certainly using Distort software, I can't seem to replicate this (it takes a lot of second and third before I can pick up any difference, "warmth" or otherwise) but I'm a sample of one.
Yes.

The Distort software does not do distortion rising with frequency according to its designer, although he said he had written the code for it but never released it because he thought the idea was a too arcane for most people. But most amps using feedback have distortion rising above a certain frequency (dependent on the GBP and how much loop gain is in the design). So without that feature Distort is a bit of a red herring if your goal is to model how audible distortion is in most amps.

As you know the ear treats the 2nd and 3rd as being pretty innocuous, so yes, you have to add a lot to really hear it. IIRC GE did a study back in the 1960s that concluded that people will tolerate up to 30% THD if its all 2nd but I read that in a book and never found it online. Of course there was something similar to this effect published in the early pages of the Radiotron Designer's Handbook, 3rd edition (published in the 1930s). I was clued into that bit by John Curl.

Right now I'm of the opinion that distortion vs frequency might be more important than actual THD in terms of how audible the distortion might be. Its worth noting that many class D amps of the self-oscillating variety such as Hypex tend to have no rise in distortion with frequency because they have excellent GBP values, like a lot of the better opamps around these days. So they have that plus very low THD to start with- a one two punch.

Regarding evidence, did you try the demo test I mentioned a little bit ago- the one with the amp, speaker, generator and VU meter? If no, its really worth doing because otherwise its hard to understand how the ear can be so sensitive to higher ordered harmonics. After you do that demo, its pretty obvious. That's the first bit of evidence.
 

Glint

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Alot of the Chi-Fi 'invasion' was cheaply shipped little class D amps, (and DACs, and headphone amps, and combos of the lot) and frankly they sounded just fine at a fraction of the cost of traditional, bulky A/B amps. I'm sure that alone ruffled a few feathers.

They also suffered from boring aesthetics, small boxes compared to glorious knob-riddled panels.

I replaced a Yamaha A-S700 with a tiny Topping amp though as so much of the Yamaha box was unused functionality, and unused power (I have neighbours), and the Topping did the job of amplification and source selection just as well for me.

They also run quite cool, again leading to their diminutive size, and it's a well known fact that the hotter your amp runs, the better it sounds, which is why class A sounds so good, because of the heat making the electrons sound better.

There may be more to the lack of class D take-up, but like most things "audiophile", sound quality was probably one of the last things taken into consideration.
 

mhardy6647

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I was reflecting on the title of this thread as I perused "new posts" here this morning -- thinking about audiophile generalities.
My epiphany: true audiophiles are generally a grumpy lot.
;)

PS I am going to strive to be chipper today, at least online -- so don't y'all trigger me!
:cool:
 

Vacceo

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Alot of the Chi-Fi 'invasion' was cheaply shipped little class D amps, (and DACs, and headphone amps, and combos of the lot) and frankly they sounded just fine at a fraction of the cost of traditional, bulky A/B amps. I'm sure that alone ruffled a few feathers.

They also suffered from boring aesthetics, small boxes compared to glorious knob-riddled panels.

I replaced a Yamaha A-S700 with a tiny Topping amp though as so much of the Yamaha box was unused functionality, and unused power (I have neighbours), and the Topping did the job of amplification and source selection just as well for me.

They also run quite cool, again leading to their diminutive size, and it's a well known fact that the hotter your amp runs, the better it sounds, which is why class A sounds so good, because of the heat making the electrons sound better.

There may be more to the lack of class D take-up, but like most things "audiophile", sound quality was probably one of the last things taken into consideration.
Winter over here is not exactly soft. Since I built a watercooled loop on my PC and with the help of the class A/B amps of the Marantz AVR, I haven´t used the radiator in the room for a couple years.

I really hope I can transition to a multichannel amp on class D soon, because in winter it´s quite fine, but in summer, it´s not at all.
 
D

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Winter over here is not exactly soft. Since I built a watercooled loop on my PC and with the help of the class A/B amps of the Marantz AVR, I haven´t used the radiator in the room for a couple years.

I really hope I can transition to a multichannel amp on class D soon, because in winter it´s quite fine, but in summer, it´s not at all.
That may be to a bit warmer climate the last two years as I doubt 60 W or so dissipated idle power from an AVR would heat your room very much. I also don't think the change to watercooling on your PC has much to do with it either. Your PC is dissipating the same amount of heat as before. Now it's just going through a water filled radiator with a smaller temperature difference.
 

ahofer

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I still can't get past the extraneous comma in the threat title.
 

zorox

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So far, love my Hypex NxCore 500 mono blocks. As to the nay sayers, i think folks get used to listening to what they listen to, class ab, tube, whatever, and term class d as "unmusical" because they are so clean, power full and distortion free, therefor, something must be wrong. Not to mention less than half the weight. For those who prefer tube sound, they are availabel with vacuum tube buffers. Add $1200 to $1500 the tag.
 

Snarfie

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Ok, I know I shouldn't, but I've been reading feed back on an audiophile site on experiences with various Class D based amplifiers. (Purifi, Ncore, and a couple of others less well known to me)

I expected a bit of bias towards older technologies, but it was close to 100% against class D.

What is it that these people are experiencing? They can't all be wrong can they?

  • Is it that they miss the distortion/colour from their class AB amps?
  • Has this become normalized/expected?
  • Have they been programmed to dislike class D because everyone says it isn't as good, i.e bias?
  • Is there actually something else at play here?

Everything I hold as important in audio and electronics in general is about achieving the required performance/specs, 'the truth', or at least as close as we can economically get, am i wrong, because these people would appear to say so.
Did thought some years ago to replacing my NAD C370 amp for a Class D amp because the protection circuit getting slower an slower. Than the atleast 17 old old NAD protection circuite could be repaird for less than 50,- euro.
At the time (Hypex build class D amp's) where not top reliable because of fast switching power supplies i understand. Also replacing IC's/ eprom with specific firmware was not easy to replace you have to buy new (part) board if such board is/was available after let say 10 years. So for me at the time a no brainer to repair the now 23 year old NAD is still going strong for probably another 20 years.
Don't know if class D reliablility is still an issiue. I expected that such amp last atleast >20 years like most AB Amp's or are easy to repair.
 
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Purité Audio

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Vacceo

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That may be to a bit warmer climate the last two years as I doubt 60 W or so dissipated idle power from an AVR would heat your room very much. I also don't think the change to watercooling on your PC has much to do with it either. Your PC is dissipating the same amount of heat as before. Now it's just going through a water filled radiator with a smaller temperature difference.
It cools off a lot more efficiently. With the internal water temperature of 45 °C for several hours, I can tell you it definetly heats up the room.
 
D

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It cools off a lot more efficiently. With the internal water temperature of 45 °C for several hours, I can tell you it definetly heats up the room.
My point was that it heats up the room just as much as if it was air cooled. What kind of room is that, that can be heated by a ~100 W average dissipating electronics, a closet?;)
 

Galliardist

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My point was that it heats up the room just as much as if it was air cooled. What kind of room is that, that can be heated by a ~100 W average dissipating electronics, a closet?;)
At least this dispute should be easy to sort out, unless somebody wants to claim that the required thermometer is "not resolving enough"...
 
D

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At least this dispute should be easy to sort out, unless somebody wants to claim that the required thermometer is "not resolving enough"...
Only a power meter to measure drawn power from the PC. The drawn power is = to dissipated heat.
 
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