Amplifier class, is AB vs D important? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 9 Old 05-20-2019, 08:33 AM - Thread Starter
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Amplifier class, is AB vs D important?

Two questions:
1) Is A/B amplifier class really better than class D SQ-wise and is it universally true for all AVRs?
2) How can I reliably tell what type of amplifier is used in a given receiver? I tried to lookup specs for some AVRs and found nothing. Should receivers of D class have significantly less weight?
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post #2 of 9 Old 05-20-2019, 09:46 AM
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Quote:
Originally Posted by zefelder View Post
Two questions:
1) Is A/B amplifier class really better than class D SQ-wise and is it universally true for all AVRs?
2) How can I reliably tell what type of amplifier is used in a given receiver? I tried to lookup specs for some AVRs and found nothing. Should receivers of D class have significantly less weight?
My two cents.

Today, AB is better than D, especially if you have a medium to large dedicated theater and need true theatrical sound, or you're trying to drive authoritative 2-channel music at high volume.

In a living room setup or small room, the good Class D amps work very well from what I've heard. But if you try to drive big speakers for big sound, they get very "digital" sounding. They aren't musical enough in those applications.

I much prefer the beefy, heavy and musical sound of a good AB amp. There will be a day when Class D, or some other class, can match them in performance, but not today. They're about 90% of what a good AB amp is, in my humble opinion.

Video: JVC RS620/X9500 projector, Stewart ST130 screen, Panasonic ub820 UHD player
Audio: Anthem AVM60 preamp, Anthem MCA525 amp, B&K Reference 125.7 amp
Subs: dual SVS PC-12 cylinders
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post #3 of 9 Old 05-20-2019, 01:34 PM
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Anthem uses class D for its height channels only I believe and Onkyo and Pioneer use a quality class D module in their higher line of receivers but you just have to look up reviews to see which ones. Unless you are going to put a class AB in a tight confined space then they both can sound and perform equally as well. Class D does better in enclosed spaces though. Class AB with a linear power supply need 4 to 6 inches of top and side air gap as they are less efficient and produce more heat than class D with a SMPS.

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post #4 of 9 Old 05-20-2019, 01:40 PM
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I bought some class D ice amp monoblocks off of ebay from a china seller, and I think they sound better than the internal amps on my Denon 4500. I have three for the front stage and use class D (not ice) for the remaining 8 speakers in my atmos setup. just my two cents.
also for the record, i used to love emotiva amps, but absolutely HATE their new Gen 3 series. Something about them gives me listener fatigue after about an hour into a movie. I am now 54 and while my hearing is no where near what it used to, as the old saying goes "I know what I like when I hear it" still applys..
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post #5 of 9 Old 05-20-2019, 03:23 PM
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I can't comment on sound quality from personal experience. There are certainly some Class D amps and receivers out there that aren't low end.

Class D amps can be lighter than Class A/B amps. Check out the "pro" Class D amps like the Behringer iNukes.

Note that some people refer to Class D amps as digital. They are not; they have analog inputs and outputs. They use a switching mode, so they dissipate relatively little power in their output stage. They also can drive low impedance speakers more easily than A/B amps.

The Emotiva Gen3 amps use some sort of hybrid approach with a switching mode power supply feeding class A/B amplifiers. I use an XPA3 Gen3 to drive my LCR fronts. I like it well enough. (Runs cool.)

Hardcore audiophiles might prefer class A. Preferably with vacuum tubes. Minimum nonlinearities there. Horribly inefficient, of course.
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post #6 of 9 Old 05-20-2019, 04:29 PM
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Quote:
Originally Posted by ipca204 View Post
I bought some class D ice amp monoblocks off of ebay from a china seller, and I think they sound better than the internal amps on my Denon 4500. I have three for the front stage and use class D (not ice) for the remaining 8 speakers in my atmos setup. just my two cents.
also for the record, i used to love emotiva amps, but absolutely HATE their new Gen 3 series. Something about them gives me listener fatigue after about an hour into a movie. I am now 54 and while my hearing is no where near what it used to, as the old saying goes "I know what I like when I hear it" still applys..
Completely agree on Emotiva. I've got a Gen 1 and a Gen 3. The Gen 1 is a beast. The Gen 3, not so much. I can confidently say those two amps are my first and last Emotiva purchases. The Gen 1 has a permanent place. The Gen 3 will get replaced eventually with something else.

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post #7 of 9 Old 05-21-2019, 10:22 AM
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Some class D amps are well designed. I’ve been happy with my ATI 543NC. Though I think there are a lot more average class D amps than good, no?
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post #8 of 9 Old 05-21-2019, 10:28 AM
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Quote:
Originally Posted by Erod View Post
My two cents.

Today, AB is better than D, especially if you have a medium to large dedicated theater and need true theatrical sound, or you're trying to drive authoritative 2-channel music at high volume.

In a living room setup or small room, the good Class D amps work very well from what I've heard. But if you try to drive big speakers for big sound, they get very "digital" sounding. They aren't musical enough in those applications.

I much prefer the beefy, heavy and musical sound of a good AB amp. There will be a day when Class D, or some other class, can match them in performance, but not today. They're about 90% of what a good AB amp is, in my humble opinion.
Is there any basis for these statements? Amp topology and design doesnt matter - all amps are going to sound the same when within their operating margins, i.e. before they clip.

There's no such thing as 'digital' or 'musical', all these terms are audiophile nonsense An amp has one job - to amplify the input signal. its not supposed to change the Fr or color the sound, but some (like tube amps) do because they don't handle full range, and people start liking this sound, its no different from a DSP mode in a processor.

A digital class D amp will be lighter, consume less power, generate less heat and be be far more efficient - in other words, better in every respect. What it will not be is heavy and big - and those things are seen as a sign of 'quality', again due to all kinds of audiophile bias.

The industry is very heavily invested in selling the traditional products and any technical advances are ridiculed because they threaten the usual companies.
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post #9 of 9 Old 05-21-2019, 10:37 AM
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Quote:
Originally Posted by Defcon View Post
Quote:
Originally Posted by Erod View Post
My two cents.

Today, AB is better than D, especially if you have a medium to large dedicated theater and need true theatrical sound, or you're trying to drive authoritative 2-channel music at high volume.

In a living room setup or small room, the good Class D amps work very well from what I've heard. But if you try to drive big speakers for big sound, they get very "digital" sounding. They aren't musical enough in those applications.

I much prefer the beefy, heavy and musical sound of a good AB amp. There will be a day when Class D, or some other class, can match them in performance, but not today. They're about 90% of what a good AB amp is, in my humble opinion.
Is there any basis for these statements? Amp topology and design doesnt matter - all amps are going to sound the same when within their operating margins, i.e. before they clip.

There's no such thing as 'digital' or 'musical', all these terms are audiophile nonsense [IMG class=inlineimg]/forum/images/smilies/smile.gif[/IMG] An amp has one job - to amplify the input signal. its not supposed to change the Fr or color the sound, but some (like tube amps) do because they don't handle full range, and people start liking this sound, its no different from a DSP mode in a processor.

A digital class D amp will be lighter, consume less power, generate less heat and be be far more efficient - in other words, better in every respect. What it will not be is heavy and big - and those things are seen as a sign of 'quality', again due to all kinds of audiophile bias.

The industry is very heavily invested in selling the traditional products and any technical advances are ridiculed because they threaten the usual companies.
Considered them. Listened to them. Didn't like them.

Video: JVC RS620/X9500 projector, Stewart ST130 screen, Panasonic ub820 UHD player
Audio: Anthem AVM60 preamp, Anthem MCA525 amp, B&K Reference 125.7 amp
Subs: dual SVS PC-12 cylinders
Speakers: Jamo 626k4 in-wall mains, Jamo 631k4 bi/dipole surrounds, DefTech DI6.5R heights
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