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

[anphex]

Looking at recent reviews (Topping PA5) and the well established Class D amps from Hypex and Purifi I fail to see how - looking from at a straight rational and scientifc viewpoint - an amp should be anything besides Class D nowadays.
The Benchmark AHB2 is an exception of course but I expect to see more amps like the PA5 that deliver exceptional performance in Class D in a small and efficient form factor, and even improving over time.

This thread is not supposed to be a subjective fundamentalist discussion.

I'd just like to know technical reasons why there is still a place for A/B/AB/H in the future.

 

[Holmz]

Well most beginners could build a Class-A and drive a tweeter, and it would sound good.

Most beginners cannot build or service a Class-D.

 

[anphex]

So manufacturing complexity and I guess manufacturing price?

 

[Frgirard]

The audio world is a conservative world.

 

[Willem]

There is no good reason to design class AB anymore. It is not that they cannot be good, but a very good class D amplifier is more compact, is cheaper to manufacture and consumes less electricity.

 

[ZolaIII]

Short answer is amplitude phase shift and load tolerance.

 

[Harmonie]

Short answer is amplitude phase shift and load tolerance.

Load tolerance ?

Hypex UcD180HG HxR amplifier module analysis and review

THD distortion plot vs. power for 4ohm, 6.8ohm and 8ohm resistive load. Not that it is very important, however it is interesting to see the nonlinearity change with load. It seems that it is the output voltage that is important (8ohm load needs 1.414x more voltage to get same power as 4ohm...

www.audiosciencereview.com

 

[Bob from Florida]

Repairably speaking, I predict Class D amps will end up in a landfill more often than Class AB. So, pick your environmental poison - waste in electricity usage or waste in "waste".

 

[ZolaIII]

Load tolerance ?

Hypex UcD180HG HxR amplifier module analysis and review

THD distortion plot vs. power for 4ohm, 6.8ohm and 8ohm resistive load. Not that it is very important, however it is interesting to see the nonlinearity change with load. It seems that it is the output voltage that is important (8ohm load needs 1.414x more voltage to get same power as 4ohm...

www.audiosciencereview.com

Maximum load over declared and for amount of time.
Edit: whose trying to generalis classes AB - D. Never the less nice to know regarding HyperX which is Hybrid D.

 

[Jim Matthews]

Repairably speaking, I predict Class D amps will end up in a landfill more often than Class AB. So, pick your environmental poison - waste in electricity usage or waste in "waste".

How many units (of any type of audio gear) sold every year?

Class D is a step in the right direction, no matter how you parse it.

 

[Bob from Florida]

How many units (of any type of audio gear) sold every year?

Class D is a step in the right direction, no matter how you parse it.

The problem I see is "durability" of modern products. This is not just a "Class D" problem. Durable goods - such as washers and dryers - don't hold up like they used to. I am okay with paying more and getting reliability. Designs made to be reparable are worthwhile in the "Big Picture".

 

[SIY]

From purely a usage-for-purpose standpoint, A/AB amps are obsolete. Their attraction is more for non-use reasons: inertia, nostalgia, and visual esthetics. Sort of why I use tubes.

The arguments about "phase shift" and "load tolerance" are utter nonsense.

 

[pjug]

Repairably speaking, I predict Class D amps will end up in a landfill more often than Class AB. So, pick your environmental poison - waste in electricity usage or waste in "waste".

If this is not true then Class D manufacturers should give more than the typical 2 year warranty to help us believe otherwise.

 

[Frgirard]

They are good reasons to maintain the class AB. They are financial and industrial.
Why change what is techological masterise with a masterise cost when the client buy it.
ASR is not the audio world and the live is on the production plan.

 

[Snarfie]

If this is not true then Class D manufacturers should give more than the typical 2 year warranty to help us believe otherwise.

Reading about all the benefits around Class D amp's i was on the brink to replace my 20 year old NAD C370 for such D amp. Than the cost of repairing the NAD was so cheap that i repaired it for less than 50,- Euro (protection circuit capacitor plus some others be replaced ). After 2 years it's still going strong. I got a price if the NAD really breaks down total recapping with better parts than the original around 3 a 400,- Euro an it runs for another 20 years or probably longer due to the better parts. No wast whatsoever.

 

[steve59]

The class d amps have only recently become audibly comparable to the a/b amps so give us a little time.

 

[dshreter]

Considering that most good amplifiers sound the same it comes down to sales and marketing.

If you are developing a hifi product you need to differentiate it from others in some way that it gets interest and customers to buy. If you go with a class D design from one of the big names, it becomes very difficult to claim your amplifier for some reason sounds superior to other products based upon the same module.

The manufacturers that will survive have moved on already like Sound United / NAD and are putting their efforts into DSP, multi room, and other digital experience aspects.

 

[sq225917]

I guess we're missing the point, if you have a perfectly good class ab amp why replace it with something only a tiny bit better, but newer and likely unrepairable at its core. I can fix my neurochrome amps, I can't fix the amp board on a class d amp, just the ancillary circuits.

I can't hear the difference, so why consume the resource.

 

[steve59]

Why does someone walk when it's faster to drive? I hear the same questions leveled at audiophiles in different forms all the time on this site? why not ask fishermen why they don't just go to the store and buy whats on sale? We're really not that complicated.

 

[dshreter]

I guess we're missing the point, if you have a perfectly good class ab amp why replace it with something only a tiny bit better, but newer and likely unrepairable at its core. I can fix my neurochrome amps, I can't fix the amp board on a class d amp, just the ancillary circuits.

I can't hear the difference, so why consume the resource.

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.