Class A or B power amps - what's the difference?

wizons

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Sorry for posting about a topic that's been done to death, but what's the difference between them? Do they sound different or are any differences due to implementation in a particular amp? Which is the more reliable over time?

We all want a natural and expansive sound rather than a thin, stretched 'transistor' sound (whatever that means), but is a class A power amp any better at doing this than a class B amp.

Thanks in advance.

 
K

keirik

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It depends on your ears!

I love my class A and wouldn't change it for the world, you might not feel the same.

You could argue that class B 'might' be more reliable as they produce less heat, but I dont have any figures to back that up

seriously, you need to listen for yourself and decide

 

Frizzy brizzy

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Had both, liked both. Good examples of each around, it's the quality of design and parts that's more important than class.

A lot of amps claim to work the early watts in class a , reverting to a/b as power increases. The optimum word is claim.

class a costs more to run, due to heat.

 

Diapason

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Class A obviously sounds better than Class B, cos A is always better than B. You know, like how valves always sound warm, silver cables sound bright, Class D is barely passable, and doesn't D stand for digital anyway, so it can't be music because music isn't ones and zeros.

Where was I?

 
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Speakers that work in your room then get whatever class that drives them properly

 

iansr

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It depends on personal preference, but anyone who thinks that a good Class A amp is inferior to a good Class B amp is deaf. Ask Nelson Pass what he thinks cos he knows more about amplifiers than just about anyone else on the planet. Here's a clue: he is not deaf.

- - - Updated - - -

class D does not stand for digital. And listen to some Hypex Ncore amps before you make any more pronoun cements about switch mode amplifiers.

 

themadlatvian

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It depends on personal preference, but anyone who thinks that a good Class A amp is inferior to a good Class B amp is deaf. Ask Nelson Pass what he thinks cos he knows more about amplifiers than just about anyone else on the planet. Here's a clue: he is not deaf.- - - Updated - - -

class D does not stand for digital. And listen to some Hypex Ncore amps before you make any more pronoun cements about switch mode amplifiers.
We don't need to descend to calling even imaginary people 'deaf', surely.

I have heard very fine Class A and Class B amplifiers. I wouldn't try to start saying which is better than the other.

My present main amp is Class B (Sony ES), and consistently delights me.

I have a Class A amp in my attic system (Yamaha CA-1000) - love what it does, but by Gum it does get hot!

Don't know about Class D because as far as I know I've not heard one - could be wrong of course.

:^

 

rag

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The choice depends on the magnitude of electricity one is willing to waste. Class B is a good compromise but saying class D is 'unlisenteble' is a bit of a stretch. The ones I've purchased sound very good indeed, I have no reason to believe they cannot be made transparent like any other class.

 

bandit pilot

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Class A is my personal preference, be that valve or solid state. They just sound more musical to me.

 

Valvebloke

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... A lot of amps claim to work the early watts in class a , reverting to a/b as power increases. The optimum word is claim ...
Really ? If an amp is running in Class AB, and I suspect most of the PP amps out there are, then they must, by definition, be Class A (output devices never cut off) at low power and only move into cutoff as the signal level passes some threshold. That's how Class AB works.

As for Class B amps, I'd be surprised if there were many true Class Bs (output devices essentially cut off under quiescent conditions) on the market. They can be made, and made to work well - Doug Self's 'Blameless Bs' for example - but, as he says, they present "the knottiest problems" and I can't really see why any manufacturer would subject themselves to those just to save a few watts of dissipation over Class AB.

Class A, Class AB, Class B and even Class C (which you never see in audio, for reasons which are obvious when you know what it is) are a continuous range of classes of the same thing. But Class D is a completely different thing with benefits and issues all of its own.

VB

 

bencat

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Class A can sound more musical and have less hash but I would not claim that this is not a false wish by Class A owners such as myself. I believe a good design which sounds good is a good design and can use whatever the designer knows to work. Class a often has a limited power output so this may well be a factor given the speakers you are looking to drive .

 

Diapason

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Lest there be any confusion, I was aiming for sarcasm in my previous post, and apparently failing miserably. I really believe that people's subconscious minds get hold of some of these ideas and run with them, though.

I love lots of amps with lots of different topologies, A, A/B, D. Listen to stuff, buy whatever you like the most, etc. etc.

- - - Updated - - -

whys that then ?
Because D in an exam is only barely a pass. You want to be getting As and Bs if possible.

Again, sarcasm fail... :doh:

 
G

Guest

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I like class A, super clarity, however to get serious umph most go AB as it's ALOT cheaper to engineer, some of the switching amps i've heard are also really impressive. P.s I like valves too.

 
V

Voice_Coil

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Lest there be any confusion, I was aiming for sarcasm in my previous post, and apparently failing miserably. I really believe that people's subconscious minds get hold of some of these ideas and run with them, though.I love lots of amps with lots of different topologies, A, A/B, D. Listen to stuff, buy whatever you like the most, etc. etc.

- - - Updated - - -

Because D in an exam is only barely a pass. You want to be getting As and Bs if possible.

Again, sarcasm fail... :doh:
please excuse my utter ignorance, i was on topic, lol

of course i get it , i just didnt think for a nano second you was taking the piss, i got you all wrong, lol ;)

 

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