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Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

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Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#41

Post by kposehn »

> Nobody is having those arguments anymore. There are many class-D amplifiers on the market now, and the best of these are dominating the upper reaches of the high end.

Not quite. Frankly, Class A or AB still has the upper hand from a pure sound quality perspective, and class D struggles to output sufficiently at high levels with lower levels of distortion in my experience.

That said, there have been many small class-D Amps from Lepai and Dayton that are excellent choices for near-field and non-demanding applications. They definitely have their place. The tech is advancing rapidly but it has not supplanted A or AB.

If you want some background in why there is still debate, I highly suggest reading some of Nelson Pass’ interviews and writings:

https://www.google.com/amp/s/parttimeaudiophile.com/2018/02/... https://www.passlabs.com/press/single-ended-class https://www.passlabs.com/press/leaving-class

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#42

Post by mrob »

It's bizarre how none of these chips seem to have a digital input. All my music is digital, and despite the modern rise of vinyl, I don't think that's unusual. If I want an amplifier like this then I'm forced to have a completely useless DAC/ADC pair degrading the signal quality. Does anybody know of an easily available class-D amplifier with digital input? You'd think that would be an obvious feature for a digital amplifier.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#43

Post by taejo »

AceJohnny2 wrote: post #3
scblock wrote: post #2

Oh geez they could have left this statement out: "When I wrote my previous article, class-D audio was fairly new, and audiophiles were still arguing about whether class-D amps could sound as good as class-AB or class-A units. Nobody is having those arguments anymore." Those arguments are still front and center when it comes to amplifier design, both on the manufacturer and consumer sides.

Tangentially, the placebo effect is everywhere. If it can affect tasting (wine) and hearing (audiophile gear), I'm surprised not to have noticed its affect in discussing photography. Will "computational photography" (as touted in the latest iPhones) that alters photos based on criterion of perceived quality end up bringing these kind of inane discussions there too? Edit: Never mind, I didn't factor in all the argumen…

While there are endless debates about manipulation, when it comes to actual capturing of images, the photographic community (in my experience) has a healthy dose of "the best camera is the one you're carrying" and "a great photographer can take great photographs with any camera but even a great camera won't help a lousy photographer take great photographs" to go with its love of gear (who can help but love gear?)

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#44

Post by Karunamon »

fermienrico wrote: post #16

It is refreshing to see these types of articles. Of all disciplines of human interests and hobbies, Audiophiles are one of the most stubborn, misinformed, anecdotal and delusional bunch. Of course I am generalizing, but every time I engage in a discussion about audio quality, it is a losing battle. Not because of lack of data or supporting evidence, but because of the fundamental dissent for data driven arguments. Yo…

Of course they’re anecdotal - listening to music is a subjective experience. If someone really thinks their music sounds better after adding $100 cable lifters and taping $50 bags of rocks to their $10,000 system, they are automatically correct. Their ears, their hobby.

It would be like saying that something can’t work because it’s a placebo - even if all they’re getting is a sugar pill, if the symptoms went away, that’s not really something that you can argue with.

I put audiophiles on the same level as sommeliers. The best wine is the one that tastes best to the drinker. You can haul out your GCMS to test the wine and your ABX testing software to test the audio and tell someone their subjective experience is Wrong, but this misses the point. We’re not talking about medical efficacy here, we’re talking about artwork.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#45

Post by Matsta »

matt4077 wrote: post #24
Matsta wrote: post #10

The majority of all active speakers produced nowadays are Class-D, it's nothing really new (and the fact they are super cheap). No idea how this guy wrote this article and didn't come across DIY Audio (or he just didn't mention it in the article). There is a tonne of information here: https://www.diyaudio.com/forums/class-d/

Your first point seems to be reflected in the article, except that, if they are correct, the high end of Class D amplifiers apparently is not "super cheap". I don't quite get the aggressiveness of your second point: surely just leaving whatever your first association to a topic is out cannot warrant such outrage? It's not like they present this article as groundbreaking innovation. Not only do they cite other DIY eff…

It comes more down to the design of the board and the quality of the other components on the board. The TPA3250 he mentions is quite a new chip, but if you look on Aliexpress for an older chip like the TPA3116 there is literally thousands of examples: https://www.aliexpress.com/wholesale?catId=0&initiative_id=S...

I imagine this guy must have found the components of a site similar to DIY Audio. It would have been a nice addition to steer people in the direction of more information if they are interested in the topic (which a lot of the comments here seem to be asking about).

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#46

Post by 8bitsrule »

Matsta wrote: post #10

The majority of all active speakers produced nowadays are Class-D, it's nothing really new (and the fact they are super cheap). No idea how this guy wrote this article and didn't come across DIY Audio (or he just didn't mention it in the article). There is a tonne of information here: https://www.diyaudio.com/forums/class-d/

If your listening needs don't involve more than 10-20 watts, inexpensive Class-D amps can sound really good through a pair of good speakers. And because of their efficiency, an external power supply only needs a handful of amps (much lighter). Win-win for me.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#47

Post by bigiain »

loser777 wrote: post #34
fermienrico wrote: post #16

It is refreshing to see these types of articles. Of all disciplines of human interests and hobbies, Audiophiles are one of the most stubborn, misinformed, anecdotal and delusional bunch. Of course I am generalizing, but every time I engage in a discussion about audio quality, it is a losing battle. Not because of lack of data or supporting evidence, but because of the fundamental dissent for data driven arguments. Yo…

(EDIT: Parent deleted argument about Vinyl) Vinyl has a few more dimensions than the "quality" aspect. I totally agree that there is no argument for vinyl offering superior quality. However, I have bought a few records simply because they were actually the _easiest_ way for me to buy something I could play back for a few albums/tracks that never saw a proper online release. It's also easier to display a 12" sleeve as…

This is a Quora answer of mine from (sigh) 2011:

I _like_ vinyl, but I'm happy to admit its almost certainly due to non-audio non-hifi reasons. I like the "ceremony" associated with cleaning the disk, dropping the needle on the lead in track, and getting up to flip it over and do it again every 5 or 6 songs. I like the cover art - there is arguably a loss to the world of a beautiful art form due to the demise of the 12" record and it's large art-work ready packaging. And, as you'll hear on a lot of '90's CDs - I like the 33 1/3 rpm flaws, the clicks, scratches, and wow and flutter - when I hear the opening bars of Tear Drops from Massive Attack's Mezzanine, I get nostalgic, not for the late nineties when it was released, but for the early eighties - that scratched, fuzzy, played-too-much vinyl sound they used - that was the soundtrack to my late teens. Whatever the minor differences in the audio reproduction, those 33 1/3 and 45 rpm noises bring back some wonderful memories... Which is enough reason for me to keep the turntable set up and occasionally spin some discs...

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#48

Post by blattimwind »

compiler-guy wrote: post #31
fermienrico wrote: post #16

It is refreshing to see these types of articles. Of all disciplines of human interests and hobbies, Audiophiles are one of the most stubborn, misinformed, anecdotal and delusional bunch. Of course I am generalizing, but every time I engage in a discussion about audio quality, it is a losing battle. Not because of lack of data or supporting evidence, but because of the fundamental dissent for data driven arguments. Yo…

Much of this is cultural driven by a historical time when we didn't have the tools to measure this stuff, and reproduction was so bad that nearly anything that changed the sound in any way could be argued to be an improvement. Those days are long gone, but the culture remains. Getting good sound out of an old victrola--which were very expensive--truly is an art. Getting passable sound out of today's average off-the-s…

> Much of this is cultural driven by a historical time when we didn't have the tools to measure this stuff, and reproduction was so bad that nearly anything that changed the sound in any way could be argued to be an improvement.

[citation needed]

State of the art distortion measuring techniques resolved something like 0.002 % in the 70s.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#49

Post by 8bitsrule »

TylerE wrote: post #30
irrational wrote: post #26

Earlier quoted context omitted.

I have some questions. My son has been taking guitar lessons using a classic guitar. Using the advice of his instructor we are getting him a begginer's electric guitar for christmas. We also need to get him an amp. Is the amp in this article the same kind of amp that you could plug an electric guitar into? I know nothing about music or instruments, but I do know about electronics so I was thinking it might be fun to…

No, guitar amps are a totally different beast with many different components.

Amen. Ask a guitarist. Kid needs a real guitar amp. And a couple of decent FX pedals.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#50

Post by milesvp »

scblock wrote: post #2

Oh geez they could have left this statement out: "When I wrote my previous article, class-D audio was fairly new, and audiophiles were still arguing about whether class-D amps could sound as good as class-AB or class-A units. Nobody is having those arguments anymore." Those arguments are still front and center when it comes to amplifier design, both on the manufacturer and consumer sides.

I'm not convinced audio engineers are having that argument anymore (which is more the audience of IEEE). I get the impression from an engineer I know who's specialized in digital signal processing, and who's done a significant amount of analog work, that anyone who's still having some of these arguments doesn't understand some of the basic maths of the problem space. That basically, you can always digitally encode an analog signal at a higher resolution and fidelity than you can reliably read said signal at any given technology level/pricepoint. Which means that using an ADC -> DAC pipeline will almost always give you better audio output with better signal to noise ratios than strict analog -> analog systems (though possibly at the cost of latency).

Where it gets tricky, is the arguments for how things like tube amps sound. There is nothing that analog components add to a sound that can't be simulated with digital transforms, but the trick is figuring out how various analog components effect the signal. For instance, my friend found that certain tube amps would overdrive components and force them out of spec, and this caused a non linearity in the response of the signal coming from the component that gave the amp it's distinctive distortion effect. Once he figured that out he was able to reproduce the effect digitally. Incidently, he's found that some guitar amps can never be made today, because they were built around a specific batch of a given component, and newer batches didn't have the same out of bounds responses. But this seems to be why so many people are still so big into analog amps, because it takes considerable effort (and apparently engineering skill) to reproduce some of the classic sounds.

Mind you, I'm biased by one of the best engineers I've ever met, so I could be wrong about the general consensus with audio engineers. I'm also mostly using a sample size of 1, though I have corroborated some of his assertions with some of the blogging I've read on the topic. One of the best (I wish I'd bookmarked), was a good overview of encoding by a prolific codec writer, who pointed out that even though a digitized sine wave looks lossy at a low sample rate, it's trivial to rebuild that sine wave perfectly, with just the digitized version (so long as the sample rate was above some multiple of the Nyquist frequency?).

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