Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap • Hacker News Board

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

#201

Post by archi42 » Thu, Nov 01, 2018, 12:44 PM UTC

irrational wrote: post #26

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/

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…

For a beginner, I'd get a decent, pre-built guitar amp that "just works" with decent sound and only basic controls (as opposed to a digital amp with millions of mediocre effects). You can always add some DIY effect pedals, or get a whole new amp - but if your son wants to practice and needs to fiddle with the electronics because something is not right again with the DIY amp, this might distract him too much from actually practicing his instrument.

Maybe take him to a store so he can find out which guitar/amp combo he likes most.

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

#202

Post by squarefoot » Thu, Nov 01, 2018, 12:57 PM UTC

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…

They don't have it because they aren't digital at all; a Class D amplifier essentially is to amplifiers what a switching power supply is to power supplies. They're still 100% analog, but they use a different driving method compared to their traditional linear counterparts to maximize performance.

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

#203

Post by pimeys » Thu, Nov 01, 2018, 1:03 PM UTC

S_A_P wrote: post #179

sjwright wrote: post #143

Earlier quoted context omitted.

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…

I don't know can I judge him. I listen to music all the time. Every imaginable genre that I happen to like. I'm not putting hundreds of thousands to my setup, but a good pair of headphones and a good headphone amp is a must for me in every office I work. Put some cash for Beyerdynamic DT-1770 Pro and been having a handmade headphone amp for the last 15 years, still using it. The sound cards differ, but now I'm ok with a Dragonfly serving the system.

If you spend most of your day wearing headphones, you might invest to them a bit.

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

#204

Post by kozak » Thu, Nov 01, 2018, 1:05 PM UTC

tobyhinloopen wrote: post #162

Karunamon wrote: post #44

Earlier quoted context omitted.

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…

I have $2000 speakers and I use a $60 2nd-hand amp from 1999 and a $20 bluetooth dac with them. Audiophiles hate me. Bluetooth is the greatest sin, apparently. I have AB tested my amp with newer models and while there was a difference, it was very minor and not worth upgrading IMO

If you're listening to uncompressed (losslessly compressed) audio, you're mostly fine with Bluetooth. But if your source is already lossily compressed, they you're multiplying the artifacts of MP3 or AAC by the artifacts of aptX or SBC, and that becomes very audible if you know what to listen for.

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

#205

Post by TheOtherHobbes » Thu, Nov 01, 2018, 1:21 PM UTC

setquk wrote: post #163

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…

I’ve heard such things. Two points to note: 1. Decent monitor headphones or speakers sound the same. That’s under $500. Even some Sennheiser HD25’s are literally up there. 2. The equipment used to record such music cost less and was lower quality. Adding $500k doesn’t add anything because there isn’t anything there. Then again I have no problem with people who spend $500k on audio kit. That’s up to them. If it makes…

Not actually true about recording equipment. Top end mixing desks cost > $1m. Top end engineers and producers usually have at least $100k of outboard processing on hand - everything from mic preamps to vintage compressors. Top end mastering studios will work with similar budgets.

Add exotic guitars, vintage synthesizers, and other esoterica, and the total hardware budget for a mainstream commercial hit album is comfortably high six/low seven figures.

Some genres - mostly electronica - are 100% "in the box", generated and mixed with software. But they're usually still mastered in a high end studio with a combination of digital and analog tools on reference-grade monitors.

But all of that equipment is used to produce recordings that "translate" - play well on everything from ear buds to high end systems. That requires processing of its own.

True hifi recordings that aim to be as transparent as possible are very rare.

There's no such thing as "transparent" in pop/rock because it's all artifice. But even in classical recordings the sound has usually been edited and significantly processed, so the abstract concept of fidelity doesn't really apply.

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

#206

Post by 52-6F-62 » Thu, Nov 01, 2018, 1:27 PM UTC

crispyambulance wrote: post #196

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…

It's very easy for an audiophile to start going down the slippery slope into madness. It usually starts with amplifiers, then speakers, then source equipment... and then they start rearranging furniture, tearing out drywall and putting absorbers everywhere, and then it starts all over again in a cycle. I find it best to stick with a nice comfy pair of headphones and keep expectations low for everything else. If you'r…

I used to sell medium-high end audio visual equipment in Calgary during the height of the oil sands boom. Plenty of money moving around.

I knew customers who built the foundation of their homes around speaker placement, having separate foundations for their towers so that fewer resonant effects from the house would impact the speakers. Haha. Madness is right!

And that $500,000 number is easy when you’re dealing with those circles for sure.

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

#207

Post by chadcmulligan » Thu, Nov 01, 2018, 1:35 PM UTC

toomanybeersies wrote: post #138

chadcmulligan wrote: post #64

Earlier quoted context omitted.

Yes the noise surrounding headphones is incredible (pun not intended), even stranger I find the denigration of 'studio monitor' quality very odd. Recently I bought a nice pair of headphones, naturally enough I wanted the ones that colour the music the least, went looking in the headphone section at the nearest consumer electronic shop for the ones that were on their web site and couldn't find them. There were stands…

Well of course, you went to a consumer electronic store. The kit they sell there isn't really meant to be for "professionals". It's the same for everything they sell at those shops. They are there to upsell shiny shit to people who don't know what they want. Try finding a decent laptop for a decent price at one of those stores.

It wasn't so much that, sure, a consumer electronics shop wouldn't have professional equipment, it was the disconnect between reality and what was being presented as the best.

I've been a bit of an audio enthusiast for about 30 years and back then the expensive stuff was definitely better (mostly). Now its the opposite, the more expensive the stuff is, the worse it is and the dialog surrounding it has become cargo cult mumbo jumbo. I find it disturbing.

In general for laptops performance/cost is still vaguely linear, even in consumer shops, with audio its just a lot of noise even from supposedly professional shops.

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

#208

Post by utopcell » Thu, Nov 01, 2018, 1:36 PM UTC

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…

What did he listen to ?

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

#209

Post by scns » Thu, Nov 01, 2018, 1:40 PM UTC

pimeys wrote: post #203

S_A_P wrote: post #179

Earlier quoted context omitted.

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…

I don't know can I judge him. I listen to music all the time. Every imaginable genre that I happen to like. I'm not putting hundreds of thousands to my setup, but a good pair of headphones and a good headphone amp is a must for me in every office I work. Put some cash for Beyerdynamic DT-1770 Pro and been having a handmade headphone amp for the last 15 years, still using it. The sound cards differ, but now I'm ok wit…

Have you checked out the O2 headphone amp by nwavguy? It is mentioned in a toplevel comment in this thread.

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

#210

Post by AnthonBerg » Thu, Nov 01, 2018, 1:51 PM UTC

ballooney wrote: post #172

AnthonBerg wrote: post #167

Earlier quoted context omitted.

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.

I'm going with an understanding similar to what is presented e.g. here: https://www.mwrf.com/components/learn-meaning-amplifier-line...

"The term linearity derives from an amplifier's linear relationship of input power to output power which, in an ideal amplifier, would be precisely related by the gain of the amplifier."

I see it as matching my argument.

Could I ask you to give a definition which clashes? Thanks!