Had class D bested class A or A/B?

yd

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I have an amp that coming on 30 years old now. It could die any day and not owe me a nickel. Its an old Jeff Rowland model 8T; 250 watts, class AB but with some initial watts in A (I don't know the spec on that but pretty sure that is the case).

Rowland doesn't make A/B amps any longer and switched to D I'd say 10 years back maybe but their prices are, well shocking.

Anyhoodles, I was asking Borresen about their speakers and what kind amps might work best. They of course mentioned their own Aavik line which are also some flavor of class D. What was interesting though was the comment the reply came back with included this "I wouldn’t look at Class A/B any longer. Those designs are based on output devices that are more the 30 years old in construction. In my opinion, these designs has been surpassed by Class-D amplifier several years back. You can still get the best of the best from pure Class-A amps but they are very expensive then."

So I am thinking, well, even relatively normal AB amps still do a certain amount in class A so certainly they can't be obsolete. Just from the top of my head for instance, Pass Labs makes a 260 watt class AB amp but its first 34 watts of output are in class A. They make a 600 watt behemoth has its first 100 watts in class A. Bryston makes a nutter level 1000 watt amp and its first 25 or so I believe is in class A.

So really, is class D this new wonder or is this just same thing done differently? I gather, in theory, they can be done cheaper via class D (Jeff Rowland excluded as well as Aavik) and smaller and with less power consumption, but sound quality wise, are they really 'all that'? I have read reviews on some and they certainly are not uniformly praised as the b all and end all of amplification.

Current thoughts? Any electrifying ideas? Are they shockingly good or no? hehe, electric puns free of....charge!
 

Kyuu

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Hypex- and Purifi-based class D amps are basically beyond audibility on all metrics. Just get the power you want and you're set with amplification. Class AB works fine too and there are good designs there (including really good ones like Benchmark AHB2). But of course class D is more efficient, which results in lighter and smaller devices which use less power.

For lower-end class D amps, you do need to watch out for load dependency in the frequency response.

You should read up on it and check amplifier reviews on audiosciencereview.com. There's a lot more expertise on this subject there.
 

w00key

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This thread is relevant: https://www.audiosciencereview.com/forum/index.php?threads/is-sinad-around-5-15-khz-relevant.55839/

And especially this post: https://www.audiosciencereview.com/...-around-5-15-khz-relevant.55839/#post-2034104


Class D "weakness" is when you send a crazy amount of power, like 100W into a tweeter. Sure, then you have "only" 60 dB SNR. But who the hell listens to an ear piercing and tweeter destroying beep?

Practically, it's nonsense. Music doesn't have tons of 5 khz+ power and 95% of the 100W you output IRL is for low to mid frequencies, not cymbals or a frequency sweep.
 
I built and played around with a class D audio amplifier 40+ years ago, while the audio was certainly passable, it threw off some horrendous RFI.

Now, 40 years of improvements, and obviously experience with the ubiquitous switching power supplies has certainly solved many issues.

Class D's are all about energy efficiency and/or being light weight. Keeping those down in portable/mobile devices is paramount. At the other end the cooling requirements and weight needed to fill an arena with sound heavily favors class D.

The home enthusiast is in a nice niche where AB can comfortably reside, or if you're looking for a space heater there's always some nice vacuum tube class A's around for your needs.
 
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Kiru

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Different use case, but I'm currently using class D JL Audio amps (HD series) in my car system (since 2009).

Back in the '90's I used class A or AB, but obviously those amps were large and power-hungry (you could cook eggs on those amps after 30 minutes), so installing in a car trunk took some thought and modification.

These JL class D amps are small, so they're able to fit in a small storage compartment in my wagon, and they can make my arm hair move for hours without breaking a sweat or taxing my alternator:
Jetta_Trunk_2sml.jpg
 

yd

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Different use case, but I'm currently using class D JL Audio amps (HD series) in my car system (since 2009).

Back in the '90's I used class A or AB, but obviously those amps were large and power-hungry (you could cook eggs on those amps after 30 minutes), so installing in a car trunk took some thought and modification.

These JL class D amps are small, so they're able to fit in a small storage compartment in my wagon, and they can make my arm hair move for hours without breaking a sweat or taxing my alternator:
Not a car audio guy really - I take what comes with and thats good enough for me. But yea, that is a sweet looking install there.
 
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I'm not an audiophile and don't track amps and receivers carefully at all, but: my understanding is that a class D will work very well in nearly any circumstance, as long as you buy a reasonably good one. As far as I can tell, there's really no reason for As or ABs anymore. You will never be able to tell the difference between A, AB, and D in blind testing, as long as all of them are competent.

This, btw, is why audiophiles hate blind testing so much. They want to feel like they have special ears and special equipment, and blind- and double-blind testing proves they're wrong, pretty much every time. I remember seeing an audio forum where they actively banned blind testing. Fantasy was the most important thing to them.

I also remember reading about an amp that audiophiles actually could pick out in blind testing, and so they all swore by it. But when it was analyzed, it was actually doing a completely shit job of amplification. The reason they could hear the difference was because it was wrong, but they praised it to the skies.

Amplification is a solved problem. There's no reason to obsess over it. Same with DACs. You just need competent equipment, and will get pretty much nothing out of spending more money on electronics.

Speakers matter. A lot. Electronics, not so much.
 
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AndrewZ

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Amplification is a solved problem. There's no reason to obsess over it. Same with DACs. You just need competent equipment, and will get pretty much nothing out of spending more money on electronics.
You missed the whole point here. The whole class A, AB, D is about power efficiency, not about sound or distortion.
 
You missed the whole point here. The whole class A, AB, D is about power efficiency, not about sound or distortion.
The original question was:

So really, is class D this new wonder or is this just same thing done differently? I gather, in theory, they can be done cheaper via class D (Jeff Rowland excluded as well as Aavik) and smaller and with less power consumption, but sound quality wise, are they really 'all that'?
So, no, the question was not about power efficiency, but sound quality.
 

w00key

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Yup and sound quality of pretty much anything is nowadays decent enough. There are very few cases where a DAC upgrade or well sized amplifier will improve things audibly.

Hungry headphones for example, but I must say that even a basic Realtek on board amp is fine for my 300 ohm Sennheiser HD 650, and running on an extra hungry bass boosted / house curved oratory1990 Equalizer APO preset. Will a standalone DAC Amp combo measure better? Sure. Will I hear the difference? Not sure. Not really vs a fancier Essence STX card.
 
even a basic Realtek on board amp is fine for my 300 ohm Sennheiser HD 650,
If that output isn't extra-amplified, you'll get noticeably better sound quality from more power. The bass will be better and the soundstage will be crisper. At lower power levels, HD650s tend to kind of muddle things together a little. I remember testing my set for the first time with a headphone amp, and being able to point at the instruments I was hearing. Before that the soundstage was sort of a jumble. (my main test being the first couple tracks of The Phantom Of the Opera.)

They still sound good with regular power, but having an output that can genuinely handle 300 ohms is nicer.

If your headphone output is amplified, then the DAC itself is likely to be fine. There are some Realtek chips that don't have super S/N ratios, but if the motherboard maker talks about having good sound quality at all, it should be excellent. ASUS, for instance, is quite good at providing first-rate headphone outputs on boards with that feature.
 

w00key

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If that output isn't extra-amplified, you'll get noticeably better sound quality from more power.
There's something built in yeah. Plug in a headphone and you can set impedance to low, medium and high (300+). Okay so maybe this isn't the cheapest board you can find, but I was impressed with it.

Non extra amplified, so like a phone or Nintendo Switch via a silly looking 1/4" jack to 3.5mm TRS adapter, has lowish volume and you can definitely hear a difference, even comparing at same volume. It's a hungry beast, that headphone.
 
There's something built in yeah. Plug in a headphone and you can set impedance to low, medium and high (300+). Okay so maybe this isn't the cheapest board you can find, but I was impressed with it.
I have a similar board, and it sounds phenomenal on my HD650s. I have a little dedicated headphone USB DAC/amp that was very high quality when I bought it, nigh on twenty years ago, but the motherboard output is at least as good. My ears have deteriorated enough that I'm not sure the motherboard is actually better, but it probably is. As far as I can tell, it's equal or superior to anything I've ever heard.
 
So really, is class D this new wonder or is this just same thing done differently?

All I can add is this Schiit post (pun intended) from Jason Stoddard (Schiit audio lead). His other articles are also worth reading.

https://www.head-fi.org/threads/sch...bable-start-up.701900/page-7224#post-17354025

  • Big and hot? Makes other people go, “you’re crazy, dude!” That’s Class A.
  • Small and cool? Makes other people ask, “where’s your amp?” Not Class A.
  • Power drawn from the wall varies? Not Class A. (Thanks GoldenOne)
  • Power draw rating is lower than "Class A" power rating? Not Class A. (Thanks GoldenOne.)
 

SuperDave

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Anecdotal "data:"

There's a Hypex NC502MP-based amp (from Buckeye Amps, to offer an unsolicited plug) driving my home system. It provides +/-270wpc unless you're wiling to accept SINAD greater than "barely measurable," in which case there's more. I'm driving it balanced from the pre, meaning I can fully volt the amp and potentially use all it can offer. It would shatter my R3's on what the amp can feed at 1%THD. It cost me $700, and if it has sonic faults I sure can't hear them.

A cheap Chinese Aiyima T9 with a tube front end and Class D amplification drives the LS50's on my desktop; it's a little warmer-sounding than the Hypex (I've A/B'd both speakers on both amps) but has all the power the Metas need in nearfield, I <3 the sound and have a little over $100 in the amp.

Mind, if I win the lottery I'm going to buy a Benchmark ABH2 and a pair of Maggies, but as long as I have normal human finances I can't justify Class A/B cost for the power when Class D is now this_good_for_this_cheap.

But this is an anecdote, and take it that way.

If you want something even better, Bruno Putzeys moved on from Hypex to found Purifi and his newest designs are that, somehow, statistically. Just be aware, certain "slap your brand on the board" resellers (especially ones with recognizable brand names) are greatly inflating the actual cost of offering boards from either source without adding operational value. Good stereo amplification isn't expensive any more because of easy availability of commercial board-based amps enabling Average Joe tinkerers to produce stuff 100% competitive with the "names."

Like my amp(s).
 

w00key

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I would argue that DSPs are more important nowadays than that. When I was looking into buying an amp for my desktop, I couldn't find anything with Audessey / Dirac Live for a reasonable price*.

My workspace has shitty acoustic, I am certain of that, so who the heck cares about a -60dB noise when there are multiple 20+ dB sized room mode peaks and nulls.


* My rule of thumb is spend more on speakers than electronics, so a €250 pair is really hard to match with any decent 2 channel desktop amp with room correction. Maybe I should just give up and DIY with REW + Umik + Equalizer APO, the basic EQ should fix the worst of it. Too bad it doesn't work then for other sources like game consoles.
 
* My rule of thumb is spend more on speakers than electronics, ...
Always put the majority of your system costs towards the transducer/headphones, then move down the chain to the DAC, amp and cables, if you prefer. If you have CD/turntable spent more on them, they last a long time nowadays with no new formats - not counting all the digital format popping up every couple of years with like 5 albums to use them.
 
My rule of thumb is spend more on speakers than electronics, so a €250 pair is really hard to match

I think the version of Audyssey you really want is MultEQ XT32; per @continuum, that's the desirable option, better than the non-32 version that I have here. But even the lesser XT flavor comes in $1200 retail receivers; I got mine refurb for $710, but that's a lot more than your speakers. And then Dirac Live doesn't even start until you get into $2K+ receivers, and you have to pay several hundred dollars more to turn it on.

I love room correction, it really sounds good here, but it costs a mint.
 
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yd

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Was at a shop today and what was interesting was hearing a system playing an 88db efficient sealed speaker. The amps in question were, hold your breath, Momentum M400 monoblocks from Dan Dagostino. I think they were like, 40,000 dollars. I wasn't there for the amps, I was more interested in the speakers (Magico).

Anyhoodles. What surprised me was how much power they indicated was being used to listen to not particularly loud music - I mean, conversation over music in background ever so slightly loud'ish. If those meters were/are even remotely accurate, the draw was ranging between 15-100 watts. Not having a party, nothing demanding. I am sure everything could have driven that volume level, I was just quite surprised (assuming the meter is accurate) how much was being drawn even if only for short term peaks.

I always kinda thought I was waaaay over-powered with a stereo 250 watt amplifier but based on those meters, dang, my parties in the past would have been most certainly using the whole meter (if my amps had one).
 
To truly replicate those high frequency transients that young audiophiles love you need that peak/transient power capability. I have a nearly 50-year-old amp rated at 550 rms watts/channel with peaks around 1200 watts. That's dangerous if accessible to infants/toddlers, oldest son was using it to climb to a standing position, used the preamp volume control for support. I dove for it, it was maxed for maybe a second, the woofers survived, the tweeters were a puff of smoke, the spawn was a crying ball on the floor.

At 65 years old the average hearing loss at 8 kHz is on the order of 60 dB and deteriorating fast as the frequency increases.
 
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pauli

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I'll reiterate the earlier mentioned fact that amplification is a solved issue. Unless you want something that distorts in a particular manner, you are fetishizing a specific technology or methodology, or spending money is a goal in and of itself - a good class D is fine for anything that involves amplifying sound for humans to listen to.
 

yd

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To truly replicate those high frequency transients that young audiophiles love you need that peak/transient power capability. I have a nearly 50-year-old amp rated at 550 rms watts/channel with peaks around 1200 watts. That's dangerous if accessible to infants/toddlers, oldest son was using it to climb to a standing position, used the preamp volume control for support. I dove for it, it was maxed for maybe a second, the woofers survived, the tweeters were a puff of smoke, the spawn was a crying ball on the floor.

At 65 years old the average hearing loss at 8 kHz is on the order of 60 dB and deteriorating fast as the frequency increases.
Ouch, like, double ouch.

I have blown up an amplifier once but never a tweeter.
 

yd

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I'll reiterate the earlier mentioned fact that amplification is a solved issue. Unless you want something that distorts in a particular manner, you are fetishizing a specific technology or methodology, or spending money is a goal in and of itself - a good class D is fine for anything that involves amplifying sound for humans to listen to.
Not disputing that, I went for the speakers primarily, the rest of the gear was, well, unreal. They had a turntable worth 380,000 bucks.....not owning a single record, yea, not really my jam.
 
I think it was Ginza in the early 1980's, even then the turntables were awe inspiring, the engineering aimed at acoustic isolation and constant rotation speed was without peer. I remember one involving a load of stacked wood, a several hundred pound granite block, and a cast aluminum cylinder that was likely over 100 pounds. IIRC those prices include a crew to setup the turntable and periodic tune-ups.

I settled for a Pioneer PL-L800 turntable and added a single beam CD player at some point so I could play some of the dozen or so titles released at the time. The new digital format impressed, the single beam player could skip just like a turntable, especially at high volume. Newer triple beam players eventually solved that issue.
 
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yd

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They may have had a turntable that they priced at $380k, but they did not have one that was worth $380,000. :judge:
Just for some chuckles...yea, this was quite a room. Turntable in question is the top center item. Quick math I see 380+350+45+45+80+40+dunno another 100+ so basically a million in equipment. Interestingly, the dead center largest amp is actually only half of a pair, the other one was not there for some reason which I gather if you had your own power plant can pull almost 12,000 watts from an outlet and 100 amps. I think you would be playing music....for a neighbor.....in a different country.

UpO3hJI.jpg

The speakers are a bit small if I am honest - heck, they are smaller than my current Radians.
 
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yd

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You sure it's not just for the subwoofer which you built into the structure of your house/building?

Old school like the Capitol Studios with its subterranean echo chambers, not the licensed software emulations.
Hehe, nope, it was this (well, one of the pair) and it wasn't hooked up

https://dandagostino.com/products/relentless

Other than the bling, the metal work and heat sinks and such, delicious. My old Jeff Rowland 8t are beautiful as well but I am definitely a sucker for a power (or bias) meter. Bought my parents Schitt gear for their home but good as it is, I was really tempted by a more bog standard Yamaha integrated amp approach but the one with the power meters was like 2-3x what I paid for the Schitt setup.
 

w00key

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That's dangerous if accessible to infants/toddlers, oldest son was using it to climb to a standing position, used the preamp volume control for support. I dove for it, it was maxed for maybe a second, the woofers survived, the tweeters were a puff of smoke, the spawn was a crying ball on the floor.
Ooof. Mine loves to reach over to the piano's volume control and max it out, then ram on the keys. Fortunately Yamaha's max is just jump scare loud and doesn't destroy anything.
 

yd

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Ooof. Mine loves to reach over to the piano's volume control and max it out, then ram on the keys. Fortunately Yamaha's max is just jump scare loud and doesn't destroy anything.
Truth be told, when I killed an amp (a NAD something or other stereo amplifier), we were having a party where we hooked up two pairs of speakers to it at the same time (somehow, can't recall its configuration but must have had two sets of speaker connectors). We then uh, well, had a party. Can't recall if that was the evening the cops came for a visit. Before it blew up, I recall someone fell onto my Denon cd player and left an ass imprint on the top metal panel. Then the amp died.

Good times!

edit - I was looking just to see if my eyes were fooling me but nope, the Dan D'agostino amps in any video I have seen are definitely bouncing around in the 10-300 watt range. I can't believe what is using that much juice in any setting. My 250 watters, not that I can measure it, certainly can't be using that much power - or if they are its when I am truly in party mode. My assumption has always been speaker efficiency, 1 watt gets you that many db, double the watts to 2, 3 more db, double to 4w, 3 more db, double to 8w etc etc. To be pulling 200 watts that is 1, 2, 4, 8, 16, 32, 64, 128, 256 ie an 88 db speaker is 88, 91, 94, 97, 100, 103, 106, 109, 112 db......uh, that seems wrong.
 
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yd

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Analog meters bouncing around at a few Hz at most bear only the most tenuous relationship to what is going on in a 20 Hz - 20 kHz audio signal. A 1 ms peak might hit 300 W even though the average power over that second is only 3 W.
So in that millisecond, lets asssume everything else was just say a tone that used 5 watts but we jacked it for a millisecond with a 'blast', that blast would have transitioned out of and back into class A if one had a class A biased amp for sub say 25 watts and AB above that? As in, not meaningful indicator or power use or class of operation?
 

leet

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So in that millisecond, lets asssume everything else was just say a tone that used 5 watts but we jacked it for a millisecond with a 'blast', that blast would have transitioned out of and back into class A if one had a class A biased amp for sub say 25 watts and AB above that? As in, not meaningful indicator or power use or class of operation?
I have no idea. It probably gives you some idea of what the peak power is.
 
Just for some chuckles...yea, this was quite a room. Turntable in question is the top center item. Quick math I see 380+350+45+45+80+40+dunno another 100+ so basically a million in equipment. Interestingly, the dead center largest amp is actually only half of a pair, the other one was not there for some reason which I gather if you had your own power plant can pull almost 12,000 watts from an outlet and 100 amps. I think you would be playing music....for a neighbor.....in a different country.

... rich person tech flex omitted...

The speakers are a bit small if I am honest - heck, they are smaller than my current Radians.
That is hilarious. It would be a challenge to design a less appealing room in which to actually listen and enjoy music. Is there also a single hard stool in the exact center, where you must sit up ramrod straight to get the proper reflection angles?
 
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