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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

#171

Post by b1daly »

Karunamon wrote: post #44
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, t…

It’s not even placebo...contextual stimuli actually will change how things sound. If you have decent speakers at your computer, listen to a passage with your monitor on, then the same passage with it off, it will sound quite different.

Another example from audio production, adjusting signal processors while processing is bypassed, and being convinced the sound is changed.

Another one I’ve been noticing is how the resolution of the gain control affects perception of the “power” of the amp. If the resolution of the volume knob is high, meaning it takes more turning motion for the same level increase, the amp “feels” weaker to me, biasing my perception of sound.

The mother of all dilemmas when it comes to comparing audio gear is that the louder source always sounds “better.” This a very powerful perceptual distortion.

So while I think stereotypical audiophile practices are non-sensical, I have no doubt that they really make the systems sound better to the practitioners!

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

#172

Post by ballooney »

AnthonBerg wrote: post #167
scblock wrote: post #135

Earlier quoted context omitted.

Amplifier designers most certainly are. Class D has significant energy efficiency advantages, and significant sonic challenges. It’s taking an analog waveform, whether decoded by a DAC or starting as pure analog, and chopping it into a series of pulses (pulse width modulation). The amp is switching transistors on and off very quickly, rather than using them as a variable linear gain stage. It’s not the same as PCM en…

The thing is that transistors’ behvior is more linear and controlled when fully on or off rather than when used as continuously variable. Class-D can and does sound _amazing_ if built with good theoretical understanding. Check out Hypex amps designed by Dutch engineer Bruno Putzeys on strong control theoretical foundations.

That’s precisely and exactly the opposite of what ‘linear’ means when talking about the operating point of transistors. I think you should rephrase your argument.

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

#173

Post by tsukikage »

WalterBright wrote: post #151
mrob wrote: post #42

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 a…

All stereo components, except the amp connection to the speaker, should be ethernet. Turntable, CD player, cassette, pre-amp, everything. Then make it wifi. Just think, you could eliminate that awful rat's nest of cables. The sound quality would be better. You could locate components where-ever convenient. Each component could have a web browser interface. It'd be awesome.

Digital, sure. Standardized even, sure. But wifi, going through who knows what network stacks, routers, filtering, and sharing with other traffic? I'd like some guarantees on latency, please; I like my video in sync with my audio.

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

#174

Post by superflyguy »

dejv wrote: post #169
vichu wrote: post #4

I don't know much when it comes to audio amp design, but this reminds me greatly of the O2 headphone amp[0] - that anecdotally a few of my friends have soldered for their personal use. [0] http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html

O2 is great and it is quite simple to build. There is even simpler amp called CMoy[1] which is simple enough to be first project for somebody just starting out. I would start by taking look on some oss version[2] and order PCB from OSH Park[3]. I've built this version few years ago and it works well. [1] https://tangentsoft.net/audio/cmoy/ [2] https://github.com/akafugu/cmoy [3] https://oshpark.com/shared_projects/dR…

I built the cmoy. It was easy. But I know nothing about how it works, and I remember reading warnings on associated web pages like "this is not a guitar amp" etc. I'm curious to know a little more about how these (amps generally) work, why they're seemingly non trivial to design at a reasonable quality level etc.

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

#175

Post by drblast »

bjt wrote: post #118
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…

I would go with one of the new generation of solid state guitar amps like the Boss Katana. These are Class D amps like the one in the article, but voiced for guitar, and with distortion and reverb effects built in. They're very reasonably priced, and get good reviews from enthusiasts (much better than the solid state amps of 10+ years ago).

The Boss Katana is an ideal beginner amp that can handle bedroom practice through small gigs.

It's extremely versatile and sounds great.

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

#176

Post by neya »

After I started building my own audio gear, I am no longer impressed by what you can buy in the consumer market, no longer how much "audiophile" these systems claim to be. Usually, it's just a simple 2-way boombox sold for $xxx - $xxxx. I started my project after being disappointed with the sound quality of the Apple Homepod. So, I built my own version with inbuilt basic voice command integration. And I couldn't be happier. Funny, that I just finished building mine this week[1][2].

It's also based on Tubes, and the sound is very, very satisfying. Will be happy to share a detailed guide, if anyone's interested.

[1] https://www.instagram.com/p/Bpl71mUHLbm/?taken-by=discovery....

[2] https://www.instagram.com/p/BplhIIqHNhl/?taken-by=discovery....

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

#177

Post by WalterBright »

tsukikage wrote: post #173
WalterBright wrote: post #151

Earlier quoted context omitted.

All stereo components, except the amp connection to the speaker, should be ethernet. Turntable, CD player, cassette, pre-amp, everything. Then make it wifi. Just think, you could eliminate that awful rat's nest of cables. The sound quality would be better. You could locate components where-ever convenient. Each component could have a web browser interface. It'd be awesome.

Digital, sure. Standardized even, sure. But wifi, going through who knows what network stacks, routers, filtering, and sharing with other traffic? I'd like some guarantees on latency, please; I like my video in sync with my audio.

It would be on your home LAN, so presumably you know what else is using it. I stream video from my computer to a Roku box over ethernet, video consumes far more bandwidth than audio, and it works fine.

Also, if you plug your audio components into its own switch, it should not get interference from the rest of your LAN.

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

#178

Post by dejv »

superflyguy wrote: post #174
dejv wrote: post #169

Earlier quoted context omitted.

O2 is great and it is quite simple to build. There is even simpler amp called CMoy[1] which is simple enough to be first project for somebody just starting out. I would start by taking look on some oss version[2] and order PCB from OSH Park[3]. I've built this version few years ago and it works well. [1] https://tangentsoft.net/audio/cmoy/ [2] https://github.com/akafugu/cmoy [3] https://oshpark.com/shared_projects/dR…

I built the cmoy. It was easy. But I know nothing about how it works, and I remember reading warnings on associated web pages like "this is not a guitar amp" etc. I'm curious to know a little more about how these (amps generally) work, why they're seemingly non trivial to design at a reasonable quality level etc.

Guitar amps are very different beasts. If you want to build something simple there is "1 watt guitar amp" project[1] with many different variations.

[1] https://www.electrosmash.com/1wamp

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

#179

Post by S_A_P »

sjwright wrote: post #143
S_A_P wrote: post #123

Audiophilia is a study in contradiction. The ask is a flat "uncolored" accurate sound. The gear that sells for ridiculous prices is usually tube gear with limited bandwidth and makes ~15 watts at 5-10% (admittedly usually even order harmonic) thd. Hardly uncolored. That said, and Ive mentioned this before on HN. My (now late) uncle had a bunch of audiophile friends in Dallas. He hung around folks who had spent upward…

The three critical paths for high end sound reproduction are: loudspeakers, speaker placement, room acoustics. Of course all parts of sound reproduction matter, but those three are the ones that affect real systems in practice. Most other factors are rarely an issue and/or inferior parts have a much lower magnitude of impact on sound quality. Sufficiently good source material (256kbps AAC or better) is widely availab…

You’re absolutely right about that. I didn’t even mention how all of the drywall was replaced strategically with acoustic wall board. The entirety of the living room was gutted and refurbished to be the ultimate listening room, complete with stadium seating. Another recollection I just had is that he had a separate electric circuit run to the house(as in a second set of wires coming off the utility pole) so he could properly condition the power feeding his audio gear.

Every aspect of the room was built around the grand utopias and their placement. If you’re not familiar with them check them out here. https://www.focal.com/en/home-audio/high-fidelity-speakers/u...

The subwoofer drivers are unique in that they use an electromagnet instead of the usual strontium or neodymium permanent magnet.

I think what impressed me the most was that this guy was not annoying or in to the hand wavy audiophile hocus pocus. Just super passionate about getting everything done to get the absolute best sound even if the bang per buck was low. He had a wall of vinyl and was happy to let me pick several selections to play. From what I understand, this guy would open his home to anyone interested in a listening session. If anyone is in the DFW area and you can get plugged in to that community it seemed like a great group of folks.

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

#180

Post by [deleted] »

smcameron wrote: post #126
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…

Short answer: No. Guitar amps are weird, not like hi-fi amps at all. In a hi-fi amp, distortion is the enemy. In a guitar amp, distortion is sought after. Driving the pre-amp section of a guitar amp into clipping is extremely common and desirable . Doing the same with a hi-fi amp is not . A hi-fi amp will be typically connected to speakers with a woofer and a tweeter and maybe a mid-range, trying to accurately reprod…

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