Audiophiles, generally don't like class D amps!

[Ricardus]

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.

Someone once told them Class D sucked, and was "fatiguing," and now when their brain knows they're listening to Class D, MAGICALLY all those things are true.

Tell them it's vintage class A and they will sing a different song.

 

[F1308]

Someone once told them Class D sucked, and was "fatiguing," and now when their brain knows they're listening to Class D, MAGICALLY all those things are true.

Tell them it's vintage class A and they will sing a different song.

It sounds as a Stradivarius.

And the viola is Amati.

What do you mean by D and A ?

 

[Blumlein 88]

Mola Mola are pricey, but hardly crazy by audiophile standards. 6000 Euros or thereabouts, I think. And Bruno refuses to make up silly woo-woo nonsense to sell amps

Hard to say on pricing as they don't list prices directly on their website. In the USA you have to make an appointment or contact a snobby New Jersey outfit for that info.

Positive Feedback 3 years ago listed a pair of their mono amps as $17,200.
And the integrated is around the $12k mark. Plus a line stage at $12k is available to which you can add a DAC for $8200 and a phono stage for $3000. Definitely not $250k, but pretty pricey. You do get SOTA peformance, and unique styling.

Bel Canto's Black Line amps are $15k each if the price is still the same. They sale a trickle down model as described by Stereophile for $6k.

 

[atmasphere]

Someone once told them Class D sucked, and was "fatiguing," and now when their brain knows they're listening to Class D, MAGICALLY all those things are true.

Tell them it's vintage class A and they will sing a different song.

I have one friend who described the ARC class D amps as having 'tizz' from the switching noise. I realized he had a bias so I explained to him that to meet EU directives, the switching noise was undetectable from a few feet away using a radio device and that was at a crazy frequency well above the AM band, let alone hearing range. Then explained that at least 90% of the actual noise floor is hiss is probably from the opamps at the input, not the actual class D. At that point he seemed to calm down (he is technically trained, for real...).

Confirmation bias is hard to overcome. That would have been a lot harder if he'd not had technical training!

 

[Vacceo]

I guess it boils down to effort. The combination of DSP's, class D amps and the internet has allowed people with just a bit interest, to archive what fans that have sweated blood for decades to archive.

That is great. For a person like me, with "secondary education science" level knowledge and a bit interest, it is possible to get incredible results. For a pro, (a producer, a car audio installer, a home theatre designer), it must be insane to be able to milimetrically adjust parameters you understand very well.

 

[posvibes]

They are just a bunch of classists.

 

[Gorgonzola]

When they are so wrong about this, it doesn't give much confidence that they are less wrong about other things. But maybe that's only my bias to interpret it this way

Also, with my current understanding of confirmation bias, I don't really see what's the link between "not trusting reviewers" and being immune to confirmation bias. How would that work? "Aha, this reviewer says what I believe is true. I can't trust him!"

I'm saying believing reviewers would establish a bias which those guys don't have.

 

[kemmler3D]

being immune to confirmation bias.

This isn't a thing, everyone is subject to pretty much every bias the human brain is afflicted by.

You can't trade in your human brain for a superhuman one by learning to read graphs or avoid certain reviewers. Knowing about biases doesn't save you either, any more than knowing about circadian rhythms eliminates your need to sleep.

All you can do is adopt strategies to avoid letting the biases drive your decisions and actions. One such strategy is relying heavily on measurements over other types of information.

This strategy seems to work, but it doesn't make you immune to bias any more than buying a raincoat makes you immune to getting wet. You have to use it every time, and even then its effectiveness can vary...

If you'd like to read about all the design flaws in your "rational" mind: https://en.wikipedia.org/wiki/List_of_cognitive_biases


Here's a philosophical pickle I noticed while reading about these things. Rational decision making doesn't actually exist. What we actually do is intake rational information and then develop a positive emotional disposition towards the "rationally correct" choice, which then becomes our decision.

If rational decision-making REALLY existed, you wouldn't experience a step where you continue to weigh the options briefly after understanding the rational criteria you're using to decide. The decision would simply be made and unquestionable as soon as you understood the numbers. You wouldn't have to consciously make a decision. This literally never happens, the human brain doesn't work like that. You can see this when you find people understanding the numbers, but not liking the implication and then casting about for some other "rational" basis to make the other choice. However, the same process applies when we DO like the numbers. Food for (irrational) thought...

 

[TimF]

I have nothing new to add but let me put my 2 cents in. Products are designed and manufactured to perform a function(s) within parameters. Different classes of products in a functional line have different performance parameters. There are real world products that meet practical goals. Ninety to ninety-five percent of all modern motorcycles manufactured world wide meet practical efficiency, effectiveness, cost, and service life constraints. Most motorcycles world wide are in the 50CC to 200 cc range, by far. They serve transportation and work functions. These are real world products. The current line of Harley Davidson motorcycles are not real world products and are not meant to be. They are what we know as luxury and exotic goods, and often such goods are perversions of practical goods. Those markets thrive on illusion, perversion and exclusiveness. In the class of exotica you could include nostalgia products of which audio tube equipment is an example. The primary design objective is the predominance in one way or another of tubes, a non-negotiable fixed design constraint. In the modern world they are not practical goods but are perversions. These days they are similar to quack folk medicines and cowboy six shooters. Why waste any time or energy on them? In terms of real world functions and practical purposes, the Harley Davidson in indeed a perversion and an outlier that performs a purpose/function quite contrary to modern motorcycling. It is an offensive exclusive exotic product line, by design in a specific market niche.

 

[kemmler3D]

Why waste any time or energy on them?

Because you happen to have an arbitrary preference for them. De gustibus non est disputandum... But it gets bothersome when these arbitrary preferences are asserted to be objectively superior in some way, when the opposite is demonstrably true.

 

[computer-audiophile]

De gustibus non est disputandum... But it gets bothersome when these arbitrary preferences are asserted to be objectively superior in some way...

That is true

One lives in different worlds of values. Sometimes they clash here in the ASR.
The rationalist (narrow-minded and frugal) cannot fathom the pleasures of the senses (even those of the art lover).

 

[DanielT]

I consider class D to be the melody of the future.

There are many good class D amplifiers BUT just to spice up the discussion. There may be problems with some class D amplifiers. Here is an example of a class D based amplifier that is liked by many, but which does not work so well together with a pair of C-Note speakers:

# 212 and 216 in the thread:

Parts Express DIY C-Note Speaker Review

What amplifier you're feeding them with? It doesn't look like HF shelf/mistuned tweeter level - that curve shape tells me that some EQ or rather tone control (treble boost) is applied. Check amp and source:)

audiosciencereview.com

#212
Pjug:
Do you have a Class AB amplifier available to try with the C-Notes? I do think you are seeing peaking caused by Class D without post filter feedback, into a load with negative phase at high frequencies. I copied @pma 's curve with Aiyima A07 (thread linked in my previous post) into his dummy load, which looks similar to what you are seeing with your setup.

Frequency response of two amps into dummy load

#216
Badspeakerdesigner:

I think we have a winner, went to a friends place to test out his Audiosource Amp 100 which is class A/B. He also had an Aiyima A07 as well. As you can see the Aiyima exhibits the HF rise, while the Audiosource does not.

Guess I need a new amplifier or new xover design on the tweeter, one of those is much easier than the other so I will probably get a new amp.

__
Plus this that I posted, #647 in the thread:

New SMSL A300 BTL Class-d Power Amp

You inspired me, I went ahead and bought the plan. I don't normally buy such things but this is my first Chinese class D amp and I don't really trust the durability. Well, so far we haven't seen a Topping PA5 situation with this amp, or pretty much anything else.

audiosciencereview.com

When we are still on the class D technology. On other forums, or one that I know of, there is more skepticism towards class D amplifiers. The skepticism concerns, among other things, how tests are carried out on class D amplifiers, where it is often complained that too little bandwidth is used during the measurement. Morello is, as I quote, a good EE who designs amplifiers himself, I'll just add.The amp under discussion and Stereophile's measurements of it are this:

NAD C 298 power amplifier Measurements

Sidebar 4: Measurements

www.stereophile.com

Morello:

Note that the measurements on this class-D device are carried out with the low-pass filter (f=25 kHz) Audio Precision AUX-0025 connected between the output of the power amp and the input of the analyzer, which is why all THD measurements are irrelevant above about 6 kHz. I'm surprised Atkinson doesn't limit the graphs to just this.
....
The reason for the measurement procedure is that the analyzer from Audio Precision that Atkinson uses does not handle copious amounts of high-frequency garbage typical class-D spews out. What I object to is that THD data is still reported up to 20 kHz, even though the data is not relevant above 6-7 kHz. It is also clear that many readers of testers do not reflect on this, which is, of course, completely understandable.
.....
THD is a measure of the step nonlinearities - quadratic, cubic and higher order terms in the transfer characteristic. The same terms entail intermodulation distortion. If you want a correct picture of the amp's distortion, the bandwidth when measuring THD up to 20 kHz must be at least 80 kHz, which means that harmonics up to and including order four are included.

The Nad C298 shows high THD at treble frequencies above 10 kHz, despite the fact that the numbers are heavily embellished due to the low-pass filter used in the THD measurement.
(with reservation for inaccuracies via google translate)

New SMSL A300 BTL Class-d Power Amp

You inspired me, I went ahead and bought the plan. I don't normally buy such things but this is my first Chinese class D amp and I don't really trust the durability. Well, so far we haven't seen a Topping PA5 situation with this amp, or pretty much anything else.

audiosciencereview.com

 

[tuga]

Hard to say on pricing as they don't list prices directly on their website. In the USA you have to make an appointment or contact a snobby New Jersey outfit for that info.

Positive Feedback 3 years ago listed a pair of their mono amps as $17,200.
And the integrated is around the $12k mark. Plus a line stage at $12k is available to which you can add a DAC for $8200 and a phono stage for $3000. Definitely not $250k, but pretty pricey. You do get SOTA peformance, and unique styling.

Bel Canto's Black Line amps are $15k each if the price is still the same. They sale a trickle down model as described by Stereophile for $6k.

£600 for a 400W Mola Mola mono:
https://nintronics.co.uk/mola-mola-kaluga.html

€750/£667.5 for a 400W Audiophonics Hypex mono:
https://www.audiophonics.fr/en/powe...-d-amplifier-purifi-1x400w-4-ohm-p-14951.html

A pair of Benchmark AHB2s will cost you £7,000.

 

[Bob from Florida]

£600 for a 400W Mola Mola mono:
https://nintronics.co.uk/mola-mola-kaluga.html

€750/£667.5 for a 400W Audiophonics Hypex mono:
https://www.audiophonics.fr/en/powe...-d-amplifier-purifi-1x400w-4-ohm-p-14951.html

A pair of Benchmark AHB2s will cost you £7,000.

Why do you mention the ABH2's? The ABH2 is a linear amplifier - https://benchmarkmedia.com/collections/all-products/products/benchmark-ahb2-power-amplifier

 

[tuga]

Why do you mention the ABH2's? The ABH2 is a linear amplifier - https://benchmarkmedia.com/collections/all-products/products/benchmark-ahb2-power-amplifier

For some the audibility of distortion is all that matters...and surely to them the ABH2 is a waste of money (poor value-for-money, rip-off, etc.).

 

[Blumlein 88]

So are those prices on the Mola Mola Kaluga for real? @tuga

Will they deliver to the USA?

 

[Bob from Florida]

For some the audibility of distortion is all that matters...and surely to them the ABH2 is a waste of money (poor value-for-money, rip-off, etc.).

By audiophile standards the ABH2 is cheap, not as cheap your other 2 examples.

 

[ahofer]

Just responding to the title of this thread:

Audiophiles usually don’t like anything that is cheaper, smaller, or more efficient. It’s a weird flex. Somebody, somewhere, is trying to figure out how to get 1000W class A from a large cage full of gerbils and running wheels.

 

[tuga]

By audiophile standards the ABH2 is cheap, not as cheap your other 2 examples.

My point is that in a "audibility is all that matters and everything that measures below audibility sounds the same approach", used earlier to characterise Mola-Mola amplifiers as pricey, the pair of ABH2 is 5x too expensive.
I am not condoning such approach.

 

[tuga]

Audiophiles usually don’t like anything that is cheaper, smaller, or more efficient.

Generalisations usually struggle to reflect reality.