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

[DimitryZ]

Just speaking from my own experience, long term reliability - multiple decades - has become worse generally. There are a lot of reasons for this, and some of it is simply the greater complexity of electronics as time passes. Also, there is more price sensitivity and the pressure to lower manufacturing costs compared to what I experienced 40 years ago. Add to that a changing mentality and expectation that electronic gadgets are not expected to last very long to begin with. Passing gear down through generations is not as much a given as with gear manufactured in the 60s, 70s and 80s. Realistically, can you picture someone, say 30 years from now, restoring a class D amplifier manufactured today to like-new working condition in the same sense that someone today might restore a Marantz 8B?

99% of old gear is not Marantz 8B, but commodity brands that went into the landfill, electrolytic caps and all.

 

[Twitch54]

If you lower the room temperature of cause you get a lower heating bill... but i don't think this is what your trying to say.

yeah, 'tongue -n-cheek' !

Your thermostats regulate a temperature assuming you increases the power output in your room you don't have to lower the thermostat. it will lower the power automatically.

Class A amps dissipate more heat @ idle

 

[rcstevensonaz]

Interesting and timely thread for me. I had been wondering whether I should look at replacing my older Class A/B amp (purchased as "open stock" in 2006) with a newer Class D amp:

Old ==> Emotiva LPA-1 (A/B)
New ==> Hypex N252MP / N502MP Multi-channel amp (D)

Based on this discussion, from an audio perspective only (i.e., disregarding cost, power usage, landfill, repairability, aesthetics), and assuming both amps meet/exceed my speaker load requirements and were competently engineered:

• I would not gain any audio benefit by moving to a modern Class D amp, and
• I would not lose any audio benefit by moving away from a Class A/B amp

Put differently, the only audio consideration is:
1) whether the Emotiva LPA-1 amp had engineering design issues that cause audible degradation in sound quality, and
2) whether failing parts in my specific amp have triggered a "repair or replace" decision?

I have really appreciated this discussion because I had just assumed that there were fundamental audible strengths & weakness between A/B and modern D amplifiers.

p.s. I'd be happy to drop off an Emotiva LPA-1 to Amir some time for testing (assuming there is any interest in "ancient" amps).

 

[levimax]

Interesting and timely thread for me. I had been wondering whether I should look at replacing my older Class A/B amp (purchased as "open stock" in 2006) with a newer Class D amp:

Old ==> Emotiva LPA-1 (A/B)
New ==> Hypex N252MP / N502MP Multi-channel amp (D)

Based on this discussion, from an audio perspective only (i.e., disregarding cost, power usage, landfill, repairability, aesthetics), and assuming both amps meet/exceed my speaker load requirements and were competently engineered:

• I would not gain any audio benefit by moving to a modern Class D amp, and
• I would not lose any audio benefit by moving away from a Class A/B amp

Put differently, the only audio consideration is:
1) whether the Emotiva LPA-1 amp had engineering design issues that cause audible degradation in sound quality, and
2) whether failing parts in my specific amp have triggered a "repair or replace" decision?

I have really appreciated this discussion because I had just assumed that there were fundamental audible strengths & weakness between A/B and modern D amplifiers.

p.s. I'd be happy to drop off an Emotiva LPA-1 to Amir some time for testing (assuming there is any interest in "ancient" amps).

I would say probably no audible difference if they are the same power. If you want to prove it to yourself I would get a Class D and set up a blind ABX test with your class AB and see if you can tell them apart. It is a bit of a project and it helps if you have some DIY skills and equipment but for me it was well worth it. While I didn't ABX a Class D vs a Class AB I did ABX of a 60 year old tube amp with a SINAD of 60 vs a new SS amp with SINAD of over 100 and could not tell any difference. It really put things in perspective for me.

 

[DanielT]

Interesting and timely thread for me. I had been wondering whether I should look at replacing my older Class A/B amp (purchased as "open stock" in 2006) with a newer Class D amp:

Old ==> Emotiva LPA-1 (A/B)
New ==> Hypex N252MP / N502MP Multi-channel amp (D)

Based on this discussion, from an audio perspective only (i.e., disregarding cost, power usage, landfill, repairability, aesthetics), and assuming both amps meet/exceed my speaker load requirements and were competently engineered:

• I would not gain any audio benefit by moving to a modern Class D amp, and
• I would not lose any audio benefit by moving away from a Class A/B amp

Put differently, the only audio consideration is:
1) whether the Emotiva LPA-1 amp had engineering design issues that cause audible degradation in sound quality, and
2) whether failing parts in my specific amp have triggered a "repair or replace" decision?

I have really appreciated this discussion because I had just assumed that there were fundamental audible strengths & weakness between A/B and modern D amplifiers.

p.s. I'd be happy to drop off an Emotiva LPA-1 to Amir some time for testing (assuming there is any interest in "ancient" amps).

Maybe instead put the money on a couple of nice:

 

[rcstevensonaz]

Maybe instead put the money on...

Thanks; but that is a bit off topic. (Also, I'm suspecting that few, if any, of those sell for under $1,800 per pair.)

 

[MakeMineVinyl]

Interesting and timely thread for me. I had been wondering whether I should look at replacing my older Class A/B amp (purchased as "open stock" in 2006) with a newer Class D amp:

Old ==> Emotiva LPA-1 (A/B)
New ==> Hypex N252MP / N502MP Multi-channel amp (D)

Based on this discussion, from an audio perspective only (i.e., disregarding cost, power usage, landfill, repairability, aesthetics), and assuming both amps meet/exceed my speaker load requirements and were competently engineered:

• I would not gain any audio benefit by moving to a modern Class D amp, and
• I would not lose any audio benefit by moving away from a Class A/B amp

Put differently, the only audio consideration is:
1) whether the Emotiva LPA-1 amp had engineering design issues that cause audible degradation in sound quality, and
2) whether failing parts in my specific amp have triggered a "repair or replace" decision?

I have really appreciated this discussion because I had just assumed that there were fundamental audible strengths & weakness between A/B and modern D amplifiers.

p.s. I'd be happy to drop off an Emotiva LPA-1 to Amir some time for testing (assuming there is any interest in "ancient" amps).

Do you need to replace your older amp at all? If it's still working you're likely not to hear any difference in sound. But if you do want to change, a good class D amplifier is a good choice.

 

[rcstevensonaz]

Do you need to replace your older amp at all?

Need? No. But to be honest, I didn't "need" the Emotiva LPA-1 when I bought it 15 years ago either; I could have just driven my speakers from the Onkyo AVR's built-in amps. In the world of audio lovers, I suspect that "need" is probably never the the right word (except in the case of replacing non-functioning equipment).

But, even replacing "do you need to" with "would you benefit from"... it seems the answer is still "No".

you're likely not to hear any difference in sound

Agreed. But further, my take-away from this thread is that I wouldn't—even more, I couldn't—hear any audible difference related to use of a Class A/B vs. Class D amplifier in the respective amps.

Obviously, poor engineering and design related issues anywhere in the end-to-end componentry of each amp could make a difference; though even still, you are probably correct that I'm likely not to hear any difference in sound.

 

[valerianf]

All the Avr that have own are class AB when my surround amplifier is class D.
Class D is smaller, generates less heat (but some heat) and sound more punchy in the low frequencies.
Problem is that a lot of class D amps have an hiss in the high frequencies.
I will not use a class D amp for the center channel and the front mid-range and high frequency drivers.

But with a bi-amp configuration why not a class D for the multiple low frequency drivers and a class AB for the midrange and the tweeter?
Could Onkyo make it with Diract that will adjust the delay between the 2 amps (D & AB)‽
My front column speakers would sound great with it.

 

[DanielT]

Thanks; but that is a bit off topic. (Also, I'm suspecting that few, if any, of those sell for under $1,800 per pair.)

It was more generally a consideration of $ vs what gives the most good sound. There are others

But, even replacing "do you need to" with "would you benefit from"... it seems the answer is still "No".

......By the way, you're a man. We men like to buy technical gadgets, regardless of whether we actually need them or not. Unfortunately, our wives have figured this out.

---

 

[Head_Unit]

No waist whatsoever.

The NAD amp? Or you personally?

 

[Head_Unit]

Class D is smaller, generates less heat (but some heat) and sound more punchy in the low frequencies.
Problem is that a lot of class D amps have an hiss in the high frequencies.

I can say no hiss at at, even ears next to the Focal 936 tweeters, from an ATI 525NC. No heat at all! Even playing kinda loud, sits at ambient room temperature. Then again, it's $3400.

 

[Snarfie]

The NAD amp? Or you personally?

Damm translater

 

[Kevinfc]

One of the positive aspects of class D is energy efficiency, especially when idling. It runs outside the discussion of an amps musical ability, but other things being equal, or even close, it makes a difference to me. I believe that class D will soon dominate the audio market.

 

[antcollinet]

One of the positive aspects of class D is energy efficiency, especially when idling. It runs outside the discussion of an amps musical ability, but other things being equal, or even close, it makes a difference to me. I believe that class D will soon dominate the audio market.

At the average power levels most are running amps at, energy efficiency is close to irrelevant. Certainly not enough to notice it in your energy bill.

 

[Head_Unit]

One of the positive aspects of class D is energy efficiency, especially when idling. It runs outside the discussion of an amps musical ability, but other things being equal, or even close, it makes a difference to me. I believe that class D will soon dominate the audio market.

It makes a difference to us too, hence the purchase of the Class D ATI 525NC. Nothing AB was considered. Also because you should be able to draw more power out of the wall socket...though I'm not sure how much that applies to peak power. I'd say Class D already dominates the total audio market. It's just a minority in AVRs and mid/high price home power amps.

 

[Head_Unit]

At the average power levels most are running amps at, energy efficiency is close to irrelevant. Certainly not enough to notice it in your energy bill.

True about the bill, but not always irrelevant, if you notice how warm AVRs can get (https://www.acinfinity.com/receiver-amp-cooling-fans/ is your friend).

 

[bkatbamna]

I like big, heavy amplifiers.

 

[antcollinet]

I like big, heavy amplifiers.

Get a big box, add a couple of house bricks, and a hypex module. Job done

 

[Gregss]

Hello,

As far as overall reliability goes - would guess that what with digital controls and displays much of, if not most audio stuff has quite a bit more complexity to break. As well there seems to be a trend to make just about everything in smaller cases, which makes heat management more critical. Believe that could contribute to an overall trend.