• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

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

jmillar

Active Member
Joined
Oct 1, 2020
Messages
177
Likes
138
Aesthetic impact and "steampunk" vibes are part of the "big, heavy and hot" amplifier ethos.
 

Snarfie

Major Contributor
Forum Donor
Joined
Apr 30, 2018
Messages
1,169
Likes
926
Location
Netherlands
Ok, it makes sense. But a well designed "class D" well built with good components and enough margin for stress should in theory have a good service life.

I guess that Class D Amps like Hypex will become better an more reliable it's a matter of time an this sort of technical innovations are going fast. Saw a topic here on ASR about Gan Systems looks like the next solution in Class D amps were it looks like you don't need a heat sink anymore.
My NAD C370 will probably survive the coming 5 or 10 years. Lets see than what is on the market. But i doudt that recapping cost at that time of my NAD will buy me a brand new Integrated Class D Amp.
 
Last edited:

mhardy6647

Grand Contributor
Joined
Dec 12, 2019
Messages
11,216
Likes
24,178
Yep, agree. "Durable goods" produced today are "better" but less "durable".



That does seem to be the case -- with "the inexorable march of technology" used to justify the built-in obsolence. And, heck, the IoT lets the manufacturer "obsolete" a product from a distance.
What a glorious age in which we live. ;):facepalm:

Sorry, I guess I'll go outside now and shake my cane at those darned kids messin' up the lawn again! ;)
 

Trell

Major Contributor
Joined
May 13, 2021
Messages
2,752
Likes
3,285


That does seem to be the case -- with "the inexorable march of technology" used to justify the built-in obsolence. And, heck, the IoT lets the manufacturer "obsolete" a product from a distance.
What a glorious age in which we live. ;):facepalm:

Sorry, I guess I'll go outside now and shake my cane at those darned kids messin' up the lawn again! ;)

That picture must be an example of what the wife of a member called “phallic brutalism”. :p
 

mhardy6647

Grand Contributor
Joined
Dec 12, 2019
Messages
11,216
Likes
24,178
That picture must be an example of what the wife of a member called “phallic brutalism”. :p
They don't strike me as particularly phallic nor brutal*. I actually think they're rather beautiful, and there's no doubt that they were carefully and lovingly restored.
They have a back story, too, sort of. Years back, one of the big local (MA) collectors (now, sadly, deceased) had restored them and was selling them at the regional swapmeet for a very nice price. A friend of mine really wanted 'em but didn't have adequate cash in hand. I did, so I bought 'em for him, got to play with them for a while, and then passed them along to the aforementioned friend (who, let the record show, did reimburse me).

They're late-'50s/early-'60s examples of Radio Shack's AF-12 mono integrated amplifier. Push-pull 6V6 so about 10 watts. Basically a Grommes "Little Jewel" clone. Early on, in fact, I think that Grommes made them for R/S, but these, I am fairly sure, were Japanese made.
They are unassuming but perfectly respectable little amplifiers, and the price at the time of acquisition was very attractive.

Speaking of very attractve... especially in the dark. :cool:

1642101413093.jpeg


"Brutal!" -- as Dave Lister of Red Dwarf might've put it. :)

1642101217761.png

source: https://www.radioshackcatalogs.com/flipbook/1958_radioshack_catalog.html
_____________
* and, no, I don't think I am compensating for anything. ;)
I will admit that the dangling wires behind them don't do much for the aesthetics of the presentation, though. :(
 
Last edited:
OP
anphex

anphex

Addicted to Fun and Learning
Forum Donor
Joined
May 14, 2021
Messages
662
Likes
870
Location
Berlin, Germany
I don't really get where you're coming from. This feels like a very subjective and biased claim to say that things are "less durable". Anything from materials to manufacturing quality, time and costs has improved so much you get way better quality for your money than back then for the same product. Inflation adjusted of course.
This is just my impression though.
 

Holmz

Major Contributor
Joined
Oct 3, 2021
Messages
2,018
Likes
1,241
Location
Australia
I don't really get where you're coming from. This feels like a very subjective and biased claim to say that things are "less durable". Anything from materials to manufacturing quality, time and costs has improved so much you get way better quality for your money than back then for the same product. Inflation adjusted of course.
This is just my impression though.

^Maybe^

But I had more fun and enjoyment for a realistic amplifier and a homemade mono speaker and daggy TT when I was 11, than with a bestbuy type of system later on.
 

skymusic20

Member
Joined
Aug 19, 2020
Messages
47
Likes
34
As far as I know today nearly any cheap device that reproduces music is class D. Your cellphone, boomboxes, bluetooth speakers, your TV, your car sterero, all in one cheap home theaters, all in one mini audio systems, big speakers for parties, laptops, cheap PC active speakers, etc, etc. As far as I know all of them have class D amps.
Perhaps people who care about audio quality and audiophiles don't want to feel they are using the same technology as anyone else.
 

levimax

Major Contributor
Joined
Dec 28, 2018
Messages
2,348
Likes
3,462
Location
San Diego
I don't really get where you're coming from. This feels like a very subjective and biased claim to say that things are "less durable". Anything from materials to manufacturing quality, time and costs has improved so much you get way better quality for your money than back then for the same product. Inflation adjusted of course.
This is just my impression though.
For many things yes but "tubes" for instance were better quality (not necessarily sonically) 50 years ago than current production tubes
 

stemfencer

Member
Joined
Feb 9, 2021
Messages
97
Likes
71
I'm in the market for my first serious gear so took the time to go through this thread of great interest as seems the AB vs D is a well balanced debate at this point in time. Can I take at summarising this?

Assuming looking to buy some new gear, not to replace perfectly working or easily repairable existing equipment, the point of differentation seem to converge on three main points from the discussion within this thread, and some searching in other pastures.
  1. Electrical consumption, which extends to financial cost and social responsibility factors around how that power was generated
  2. Emotive or intrinsic associating with a certain type of technology or form factor and how that brings joy to you in this hobby
  3. Life of product ownership experience and costs, primarily replacement and repairability frequency and ease
 

Holmz

Major Contributor
Joined
Oct 3, 2021
Messages
2,018
Likes
1,241
Location
Australia
I'm in the market for my first serious gear so took the time to go through this thread of great interest as seems the AB vs D is a well balanced debate at this point in time. Can I take at summarising this?

Assuming looking to buy some new gear, not to replace perfectly working or easily repairable existing equipment, the point of differentation seem to converge on three main points from the discussion within this thread, and some searching in other pastures.
  1. Electrical consumption, which extends to financial cost and social responsibility factors around how that power was generated
  2. Emotive or intrinsic associating with a certain type of technology or form factor and how that brings joy to you in this hobby
  3. Life of product ownership experience and costs, primarily replacement and repairability frequency and ease

#2 might be further expanded into 2a/2b with:
  • people that run low sensitivity speakers often going Class-D for raw power.
  • and those with horns, and other high sensitivity speakers, going class-A or tubes.
So it could be both technical and emotional.
 

TurtlePaul

Addicted to Fun and Learning
Joined
May 19, 2020
Messages
631
Likes
1,027
Location
New York
I feel like class D has made big technological strides but that hasn’t all filtered down to the budget tier yet, so there are certain budgets <$300 where class AB makes more sense.

For class D to really take over, we need Bruno Putzeys to make 50 watt per channel stereo module which can be used in $100 devices which are still dominated by TPA and IcePower modules.
 

sergeauckland

Major Contributor
Forum Donor
Joined
Mar 16, 2016
Messages
3,440
Likes
9,100
Location
Suffolk UK
I feel like class D has made big technological strides but that hasn’t all filtered down to the budget tier yet, so there are certain budgets <$300 where class AB makes more sense.

For class D to really take over, we need Bruno Putzeys to make 50 watt per channel stereo module which can be used in $100 devices which are still dominated by TPA and IcePower modules.
Although the £50 amplifiers on eBay all seem to be Class D, so I'd say that the very budget end is all Class D, it's the middle to upper level that is still largely AB, with tiny numbers in Class A, and of those, I think hardly any are real Class A, i.e. stay in Class A at all power levels, never mind load levels.

S.
 

mocenigo

Major Contributor
Joined
Dec 8, 2018
Messages
1,274
Likes
1,034
I think this has more to do with why new Class AB is being made. Doubtful anyone is suggesting people should discard their AB amps.

Well, the Topping LA90 shows AB has still some life in it.
 

mocenigo

Major Contributor
Joined
Dec 8, 2018
Messages
1,274
Likes
1,034
This. data shows a high end Class D performing Well with a purly Restive load.
Now do this test with you average cheap class d an an real reactive speaker impedance.
Now do this test with an expensive OTL tube amplifier and a real reactive speaker impedance.
 

H-713

Senior Member
Joined
Jan 24, 2021
Messages
379
Likes
666
Now do this test with an expensive OTL tube amplifier and a real reactive speaker impedance.
OTL tube amps are a niche product that have been around for 80 years and never had stellar performance in this regard. Your point?
 

ahofer

Major Contributor
Forum Donor
Joined
Jun 3, 2019
Messages
4,952
Likes
8,698
Location
New York City

mocenigo

Major Contributor
Joined
Dec 8, 2018
Messages
1,274
Likes
1,034
OTL tube amps are a niche product that have been around for 80 years and never had stellar performance in this regard. Your point?

That it depends not on the class but on its realisation.
 
Top Bottom