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What are the reasons to choose Class A/AB/H over D in this day and age?

ZolaIII

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It's a mith that modern DC G-H amplifiers are all that efficient, they are less efficient than D and again efficiency is in both cases determined by conversion (AC/DC) efficiency. You won't get a 90+% switching power supply in commercial products (eventually if you pay more but for your mobile or PC not your power amplifier). At best you will get higher grade one with 85% efficiency but in reality it will be about 80(D)~75(G-H) for amplifier as whole.
Other problem is typology. Not because you all are concerned about repairabiliti. If the IC is good (and we have lots of old one's and even new one's that are far from cutting edge manufacturing process [to one or two orders of magnitude]) and keept in good conditions (operational and otherwise) it will work for a very long time (more than 40 years). However other component's will work shorter as always (power rail switches, condensers and cetera). SoM is a system on module (or small PCB with IC's and everything else to form one if you like) you can not repair it and as far as you can get a new one you are good. They are very easy tu use and connect. The problem is (when it comes to power amplifiers) in a post modern digital class popularly called Hybrid or H as well like with everything else post modern classification stops to exist and development is uncertain in the sense of closed black box designs (which based on success may or may not be lost bat we cannot any more track the progress on design scale at least). Prototyping is of course much more complicated (on FPGA) and everything needs to be done in this stage as you can't adjust or modulate it afterwards (you can but it's expensive to re rute new layout for a new revision and bring it to silicone). Small to moderate batches production is rather expensive even the older lithography is used regarding IC's. So we use last modern digital class G (for differentiation) which whose precisely defined and H as inheriting its design with who knows what they added. The biggest challenge for OEM is becoming software integration and securing proper operating (seamless operating through it) not to mention long term support regarding it as OEM's can only blow the whistle if vendor failed/didn't want or just all the sudden discontinued IC for what ever reason and that's what's producing the most of e-waste. But all of those are challenges of digital age and I am certain that will be overcome to the current extent (with open source and community work mostly).
 
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anphex

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If I go into the specifics of energy consumption:
One Hypex NC400 monoblack amp draws about 15 Watts. 11 Watt in Idle, so if in heavy use I get about 15 Watt average consumption.
Since I am a heavy user - my system is switched on the second I wake up or come home from work - 8 hours use a day in a week is realistic. The energy cost in Germany is currently about 0,38 € which is 0,43 $. Yup, let that sink in. You'll probably get to this point in the near future too.

So calculating the yearly consumption I get 17,47 € per amp per year. So it's about 35,00 for two.

Now I've seen some older stereo amps A and AB that draw 200 Watt in idle. This would up me to 232,96 € per year. This is more than my air conditioning that literally saves my life during summer lol.
 

Timcognito

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It's interesting to me that on this site and this discussion rarely is the topic of different classes of amplifiers sounding different being discussed. And yet Amir and others find big differences in tests. One group cares about nostalgia, some about size, some about energy usage, some about waste, some about the commodity nature. I think but could be wrong, the OP wanted to hear about sonic characteristics and reading between the lines there are none despite the measurements. It's like clothing or art buy what you like and can afford.
 

MakeMineVinyl

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the OP wanted to hear about sonic characteristics and reading between the lines there are none despite the measurements.
Subjective impressions are not really what ASR is about. Unless one piece of gear measures perfectly and another measures horribly, there is not much of a chance that there will be audible differences, at least with electronic components.

Speakers and other transducers are another story; closely measured specimens can indeed sound different.
 

antennaguru

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If I go into the specifics of energy consumption:
One Hypex NC400 monoblack amp draws about 15 Watts. 11 Watt in Idle, so if in heavy use I get about 15 Watt average consumption.
Since I am a heavy user - my system is switched on the second I wake up or come home from work - 8 hours use a day in a week is realistic. The energy cost in Germany is currently about 0,38 € which is 0,43 $. Yup, let that sink in. You'll probably get to this point in the near future too.

So calculating the yearly consumption I get 17,47 € per amp per year. So it's about 35,00 for two.

Now I've seen some older stereo amps A and AB that draw 200 Watt in idle. This would up me to 232,96 € per year. This is more than my air conditioning that literally saves my life during summer lol.
OK, so you folks pay 2X for energy what we pay in the US. There was virtually no difference in operating cost between the Class D and Class AB amplifiers in the system I ACTUALLY MEASURED WITH A KWH METER. Yes, Class A was slightly higher to the extent of the cost of a cup of coffee per month, also insignificant but probably more expensive over there too.

So what is it that you folks are doing wrong to pay 2X for electricity? That is the real issue, not the insignificant operating cost difference of amplifiers!!!
 

Golfx

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If this is not true then Class D manufacturers should give more than the typical 2 year warranty to help us believe otherwise.
March audio gives three years and ATI gives 5 years+
 
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anphex

anphex

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It's interesting to me that on this site and this discussion rarely is the topic of different classes of amplifiers sounding different being discussed. And yet Amir and others find big differences in tests. One group cares about nostalgia, some about size, some about energy usage, some about waste, some about the commodity nature. I think but could be wrong, the OP wanted to hear about sonic characteristics and reading between the lines there are none despite the measurements. It's like clothing or art buy what you like and can afford.
On what basis do you claim they sound different? There is performance difference but not "sound" difference. I am talking about designs for the purpose of "dumb and clean" amplification. No tubes or the likes.
OK, so you folks pay 2X for energy what we pay in the US. There was virtually no difference in operating cost between the Class D and Class AB amplifiers in the system I ACTUALLY MEASURED WITH A KWH METER. Yes, Class A was slightly higher to the extent of the cost of a cup of coffee per month, also insignificant but probably more expensive over there too.

So what is it that you folks are doing wrong to pay 2X for electricity? That is the real issue, not the insignificant operating cost difference of amplifiers!!!

I measured mines also with a meter, those are no spec estimates. The Denon 3700 with enabled amps draws additional 45 Watt(40+45) alone, and this is a modern Class AB design - thought to be fair there are many amps inside.
Now look at this at the scale of many millions of people using even a just "slightly" more power consuming amp.
I bet it would add up to a few power plants. And regarding your last question: green energy.
 

Willem

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We have an energy tax as an incentive to encourage us to save energy for the benefit of the future climate. This is using market forces to move people's behaviour into the socially desirable direction. Since green electricity will be an important component of the energy transition, the tax on natural gas will actually go up in the coming years and the one on electricity will be reduced. Textbook economics.
 

ZolaIII

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I pay 8¢ EU (10¢ US) per KW (in the winter when electricity price hire is higher than the rest of the year) and for me cost difference between good efficiency class AB and G-H is neglect able let's say a coffee and a donut per year. How ever what isn't is using a normal mid class PC (with discreet GPU) for reproduction and DSP purposes which will suck 80 to 120W (and mine is actually on more efficient side for a desktop) while doing it. Mentioning this as most of us do it similar way. Of course there are 2W (5~6 peak) designs which could do it (and good licensable IP's to make one) but it appears no one in this line of industry is actually very interested in providing such product. That's why I say how you're old smartphone or even Pi 4 is actually much more advanced than SoM's that are used in audio industry for the purpose. Older Kirin flagship mobile SoC's like 980 for instance with enough integer, FP (NEON) processing power and a 256 bit main (1W peak) Tensilica DSP for example (because I did evaluation of that generation and it's adjustable math function set [from futures to instructions and algorithms used] and it's not intended for audio but vision and Ai).
 

krabapple

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OK, so you folks pay 2X for energy what we pay in the US. There was virtually no difference in operating cost between the Class D and Class AB amplifiers in the system I ACTUALLY MEASURED WITH A KWH METER. Yes, Class A was slightly higher to the extent of the cost of a cup of coffee per month, also insignificant but probably more expensive over there too.

So what is it that you folks are doing wrong to pay 2X for electricity? That is the real issue, not the insignificant operating cost difference of amplifiers!!!
Do you really think that's the right question?

Who says energy *should* be as (relatively) cheap as it is in the US?
 

ahofer

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So, since everyone seems worried about landfill electronics, what is the best way to recycle our old gear? I keep meaning to list my old stuff (Adcom, VTL, even this nearly new IFI dac), but I generally feel like I can't be bothered. The Adcom and VTL amps are heavy as hell.

I have a feeling a 1989 Bryston 3B will join the pile in the next few years, but it is still going strong.
 

antennaguru

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Do you really think that's the right question?

Who says energy *should* be as (relatively) cheap as it is in the US?
I think it’s a better question than asking why everyone isn’t jumping on the Class D bandwagon because it has ever so slightly better efficiency (pennies per month) than Class AB. See my ACTUAL MEASUREMENTS posted above.
 
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Willem

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I pay 8¢ EU (10¢ US) per KW (in the winter when electricity price hire is higher than the rest of the year) and for me cost difference between good efficiency class AB and G-H is neglect able let's say a coffee and a donut per year. How ever what isn't is using a normal mid class PC (with discreet GPU) for reproduction and DSP purposes which will suck 80 to 120W (and mine is actually on more efficient side for a desktop) while doing it.
In the Netherlands we pay about 22 eurocents per Kwh for electricity (i.e. about $0.27). So when I recently replaced our set top box that was consuming almost 2 Kw per day by one that only consumes about 0.4 Kw per day, I saved some 500 Kw per annum (i.e. some 10 % of our annual consumption), or about 125 euros/$150. This was well worth it financially, and it was also a lot quieter. As for computers, precisely for the same reason I recently replaced my power hungry desktop PC with an Intel NUC that probably consumes only a quarter of the old one. It all adds up.
 

DanielT

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It would be perfect with a really inefficient fat big class A amplifier now. Most things go up in heat. Would have been nice. In the northern part of the country they had lower than -40 C / - 40 F last night.Heat the house with an amplifier (requires quite a few now in that case). :)

In addition, expensive electricity prices right now.It is approaching 80 eurocents per Kwh for electricity! Damn, I do not want to count on what it can create for holes in the wallet.
 
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MakeMineVinyl

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Has anybody bothered to touch their finger on the output inductor of any Hypex NC500, NC502 or just about any other such module while at idle? That sucker gets hot! Hotter than really any component in an idling class A/B amp. That heat is electricity being consumed, while doing nothing else useful. Just a humble observation. ;)
 

antennaguru

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On what basis do you claim they sound different? There is performance difference but not "sound" difference. I am talking about designs for the purpose of "dumb and clean" amplification. No tubes or the likes.


I measured mines also with a meter, those are no spec estimates. The Denon 3700 with enabled amps draws additional 45 Watt(40+45) alone, and this is a modern Class AB design - thought to be fair there are many amps inside.
Now look at this at the scale of many millions of people using even a just "slightly" more power consuming amp.
I bet it would add up to a few power plants. And regarding your last question: green energy.
What about the preamp you need with the Hypex to use it as a system? Conveniently leaving that out I presume to make the Hypex appear more efficient than the Denon.

Note that my ACTUAL KWH MEASUREMENTS were for an entire minimal system playing for a timed hour and substituting only the four (4) different power amplifiers of different topologies - each for their own hour. This takes away the idle current, peak current, average current uncertainties and gets to the ACTUAL measured power used by each over an hour playing music in a real system.
 

Lambda

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ACTUAL MEASUREMENTS posted above.
A singe data point is not very interesting for the general discussion is it?
We are not talking about Your special amplifier but about amplifier topologys in generals.
Class D is clearly More efficient but how mush this all depends on implementation and the right sizing. Can’t compere a 100W class D with a 25W class A...
Even if this are just penny's for you
It all adds up with 80B. Hunan on this Planet this is maybe you don't care abut an extra "Donut" and the extra emissions and wasted recesses.
This is why there are Regulations for energy efficiency or in other paces taxes on emission. or both.


Hotter than really any component in an idling class A/B amp
Sure your comparing it with a class AB with the same power rating?
 

antennaguru

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FWIW the last time I was in EU skiing I noticed the prevalence of plug-in electric space heaters being used indoors. Maybe they should just use more Class A amplifiers for heating assistance.

So myopic the viewpoints I’m seeing here.
 

ZolaIII

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@Willem I am afraid even to ask what kind of "set top box" consumes that much and how much per hour.
NUC doesn't work for me most of the time when I need more performance (in all areas) how ever I have old laptop with lo power Pentium Y which I use fanless when silence is imperative but rather rarely actually.
 
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