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CLass AB amps v/s Class D

Marantz offers at HiFiMART.com

vilfy

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Hi all,

While most integrated stereo amps are class AB (pure class A is way to expensive)... I was recently recommended that class D amps is the future. Was told they give better soundstage and ofcourse they are compact and run much cooler.

wanted ur expert comments on whether class D are better than AB?
 

awedeophile

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There's no rule as such. Ultimately depends on how the amp is made. Many manufacturers have made a line of Class D amps and they are more efficient and compact than Class A and Class A/B amps but not necessarily better.

I have heard some Class D based amps such as the Rowland 312 which is superb and some like the Flying Moles which I didn't like at all. The ones with huge power supplies tend to sound better IMO.
 

awedeophile

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Class A and Class AB are much more better then Class D amps , Class A and AB sounds more Analog and more warm.

Hi,

Would like to know which Class A and Class D amps have you compared, as I am thinking of upgrading my amp. Thanks..
 

Srinath_Murthy

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Class D amplification has inherent distortion in it and therefore is predominantly used in lower bandwidth amplification like in subwoofers. Class D achieves about 90% power efficiency compared to about 45% and 60% respectively for Class A and AB. However, compensating circuitry to overcome the Class D distortion has significantly advanced in recent years and so Class D are now used in few audiophile grade full-range amps as well.

The summary above is the remnants in my memory when I had last researched this topic few months ago...at that time I wanted to make sure that Class D was okay for my subwoofer before I put the money down on it...
 

audiodelic

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What about Class H amplifiers.

"This topology seems to be more efficient(less heat=smaller heatsinks) than A/B but sounds more refined, smooth, detailed."

These were the comments by some people who did side by side AB testing keeping all other equipment the same.
 

suniil

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That's a non polluted environment, you can make some noise definitely ;). I've an apartment coming up in chennai [11th floor] & planning to build a seperate false wall with proper sound insulation. I hope that should help upto some level

Living 10 floors up in Mumbai has its constraints...:(
 

neo

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Two class d type amps to be considered are Nuforce & Bel Canto. The latter IMO is better.
 

soundofmusic

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Hi,

Would like to know which Class A and Class D amps have you compared, as I am thinking of upgrading my amp. Thanks..


I had an Old Musical Fidelity A1 and Alchemist Axiom ADP 26 ( if i am correct) these two are pure class A and you have to hear it to believe.
Onkyo had launched an Class D amp , Auditioning it will make you understand why i choose Class A over Class D. may be there are better Class D amps in the market , but i have not heard any apart from Onkyo.

regards
 

soundofmusic

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Interesting Article in PS Audio website.

What's the difference between Class A and AB?

Most people understand that Class A runs hotter, generally sounds better, and is typically more expensive.

The term class A refers to biasing of the output stage (in a transistor power amp). Bias is an engineering term that actually means what it implies (i.e. Leaning in one direction). By that, we refer to the amount of current flowing through the output stage.

Class A is when both devices conduct at all times while Class B is when only one device is on at any instant. These are both limiting cases and there is thus a setting between these two limits where, for small signal levels, both devices conduct but for larger levels, only one conducts. This is termed Class AB.

Class AB is not a true class, but is a very common term applied to the biasing levels used in most audio amplifiers. The output stage is biased to carry a quiescent current significantly less than half the maximum output current, (as needed for full Class A) but sufficient to keep both devices running in Class A for small output signals. However as the output signal increases, the amplifier becomes Class B with one device cutting off on each half cycle. This biasing scheme effectively moves the linearity curves toward one another resulting in a transfer curve that is more linear as it passes through the origin. This scheme approaches the efficiency of class B yet offers class A distortion levels (nearly) especially for small output levels where class B suffers most.

It is particularly significant that the distortion is reduced for small signal levels, as it is at low levels that the human ear is most sensitive to distortion.

With the exception of Nelson Pass's (Pass Labs) amplifier that essentially has one 'sex' (polarity) of output device handling the entire signal, all transistor amplifiers have (in essence) two output devices. One output device handles the positive (plus) half of the signal and the other handles the negative half of the signal. If you can envision such an arrangement, a possible problem might come to mind ? the transition area. Like a relay runner handing off the baton to the next runner, the first half of the two-device output stage 'hands over' the signal to the second half of the output pair ;this transition is the problem. As the signal goes from the positive device, to the negative device there is a moment when neither device is handling the signal, creating a 'gap' in the music.

Class A biasing in its truest form means that there is a lot of current running through these two devices all the time. When you run current through the devices, it creates heat, and the more you run through the stage the greater the amount of heat. A true Class A amplifier runs the same amount of current through its output stage as it is expected to deliver to the load (the speaker). So, for instance, a 100 watt (rated) class A amplifier draws 200 watts per channel at all times (even when there is not a signal). When the amplifier is asked to deliver 100 watts of power to the loudspeaker, 100 watts (or half of the current) goes into the load (speaker) and the other half continues to go through the output stage.

One interesting fact is that under full power delivery conditions (when the amp is putting its full 100 watts into the speaker), the Class A power amp actually runs cooler. This is because only half of the power is being converted into heat in the amplifier, while the other half is busy driving the loudspeaker.
 

kanwar

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Class-D if done correctly, will give same sonic performance of class-AB, or maybe better.
 

trittya

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This is a 5-1/2 year old thread with the last post made over 3 years ago. :sad:
At the rate development in technology takes place these days, I feel we ought to revive this thread. :cool:
Here goes

What is Class-D amplification?

Class D Amplifiers Not 'Just Audio'
http://www.extron.com/company/article.aspx?id=ts122001

Do class D amplifiers sound digital?
http://jeffrowlandgroup.com/kb/questions.php?questionid=143

I read some old articles critical of class D amplifiers. Why should I trust my ears, instead of following the pundits?
http://jeffrowlandgroup.com/kb/questions.php?questionid=142

Can I expect true sonic excellence or only good price performance from a class D amplifier?
http://jeffrowlandgroup.com/kb/questions.php?questionid=141

Do class D amplifiers sound all alike, and what is their sonic signature?
http://jeffrowlandgroup.com/kb/questions.php?questionid=136

Why is it worth while auditioning class D amplifiers?
http://jeffrowlandgroup.com/kb/questions.php?questionid=134

Why is class D technology a green technology, and why is it important?
http://jeffrowlandgroup.com/kb/questions.php?questionid=135

Cheerio
 
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Thad E Ginathom

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Microphones ... Mixing consoles ... Speakers ... ... ... We should be thankful that power amplifiers are so uninteresting, because if they're uninteresting it means that they work well.

Love it :lol:

Actually, that article is from 2006.

Nothing wrong with that: what was true then is, plus developments as you mention, true now. And, being pro/semi-pro orientated, Sound on Sound has always been a great, down-to-earth source of information. I used to buy it :D

(going out... no time to do justice to your links now, but later... )
 

koushikp

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I don't know how that question can be answered without getting into price brackets... E.g. NAD has recently improved the old 3020 now named d3020.. it's a class d.... which has got the product of the year... Will be interesting to hear once it launches in India... My hunch says when it comes to
budget amplification(below 30k)....class d may be the way to go...at higher budgets they're aren't too many choices in class d today which may be because of tech limitations or simply a much smaller market which is even interested in class d at higher budgets....which my indeed ta20 based amp will reach this week... Will do some serious comparison then with much more traditional amps...
 

asliarun

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One thing I have read about is that class d amps are fairly immune to speaker impedance swings. Although this is a very good thing, it ends up acting against them ads speakers are designed to compensate for these losses and hence sound different.

Not even sure if this is true or not. And speaker designs vary so wildly. But thought I would share to get inputs from other forum members.
 

jls001

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...at higher budgets they're aren't too many choices in class d today which may be because of tech limitations or simply a much smaller market which is even interested in class d at higher budgets....

Try:
merrill Audio Hypex Ncore NC1200 based VERITAS Power Amp Mono Blocks (based on ncore 1200 Watt module. It needs a preamp to drive it)

Devialet D-Premier D/A integrated amplifier | Stereophile.com (this is one crazy mother - integrated amp, DAC, and even phono stage!)

Offerings from Bel Canto.
 
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