Class A/B vs Class D amplifiers

[amrutmhatre90]

Hello everyone,

I have been experimenting few things in my chain, trying different pre amps, power amps and new ways of listening music. Not that I am not satisfied but wanted to learn and feel how each change in a chain affected sound, in a good or bad way.

I have a Class D Crown XLS 2002 Power amp which I was using to power Q Accoustics 3050i which were connected to Denon x3700 and a FX Audio tube-03 Tube Pre Amp. This is around 375wpc at 8ohms.

I also have a NAD 320BEE Integrated Amplifier which can be used as power amplifier, I used this as a IA until now. With Class A/B at 50wpc at 8ohms.

One day, I decided to try the NAD as a power amplifier and test it with Crown XLS. Does more watts mean better? 50wpc Class A/B vs 375wpc class D.
Few wire swaps done, and started my test playlist.

Chain tested was:
1) Rpi Streamer > Tube Pre amp > NAD > Q acoustics 3050i
2) Rpi Streamer > Tube Pre amp > Crown XlS 2002 > Q acoustics 3050i

The Result:
1) Nad 320BEE Power Amp - The result was astonishing, everything felt much smoother yet punchy, I could immediately tell the bass and mids were better, highs slightly controlled. I could literally feel bass hitting my body.
I can listen to this at high volume whole day without fatigue. At low or moderate volumes, the bass is still felt.

2) Crown XLS 2002 - I was used to listening to this combo more often , the bass was tight and controlled. But it did not hit my body like the case with NAD. Has slightly sparkly highs. This chain feels more digital and one can notice the resolution is much better.
I cannot listen to this at high volumes, or it is just me. The sparkly highs are a issue for me. At low or moderate volumes the bass is still tight but cannot be felt.

Two things to point out:
1) Why the NAD 320BEE did not sound so good as a standalone Integrated amplifier? ANSWER is Pre Amp section! I had read it online multiple times the pre amp section is weak point of the NAD 320BEE. And by using and testing it as a power amplifier alone with a different pre amp it stands true.
Not that it is bad, but my whole system came alive when I added a tube Pre amp, I even tested with my Denon x3700 as pre amp and it still sounds better than using as IA.

2) Should One use Crown XLS for music? definitely yes but with caution. Your speakers shouldn't be bright but neutral or warm can do good. Crown XLS sounds too good at medium volume for music which has instruments specially Indian music. The separation, clarity and detail is amazing. And it scores high on cost to value factor.

I have made a small video comparing how both sound with A/B testing and mixing songs:

Would like to know your views if you testes both Class A/B and Class D amps in your chain, would help me understanding things better too.

I am looking to sell the Crown XLS, i am using it lesser than I used to, but this is in my listening scenario. I Also have space issues.

 

[raghupb]

When comparing Class D amps with Class A/B or Class A amps we always bias the comparison that favors a home usage setting.
A well designed Class D amp will usually have a flat frequency response with oodles of power on tap.

A Crown amp for example is meant for the pro market.
It will be paired up with speakers that can output high SPL and will have EQ/DSP controls that one cannot host in a home environment.
In our home rigs, we sometimes don't even have a tone control circuit
When evaluated in such a pro setup, I'll bet our dinky little class A/B amps can't even hold a candle to it.

Why do class D amps, at least affordable ones, sound lean/sterile in a home setting?
Well ... they just don't have the matching components that they were designed to work with.

Class D has been making strides into the consumer audio market for 2 decades now.
Hopefully, they will become affordable so that folks will shed the "class" baggage.

Cheers,
Raghu

 

[Abhishek_]

I am also thinking of changing my current XLS 1502. Am keen on purifi amplifiers but not sure how they compare with some of the class AB offerings from indian companies.

 

[manek]

Guys

My humble opinion and I mean no disrespect to any one, and your mileage may vary.
Pls forget about the class A,AB,D topology statements/arguments one hears/reads every day about which is better. They really wont help you select a better amp. All of the above topologies are mature enough today to compete with each other as amplifiers for home audio applications from the entry level to top end. If you really want a good amp, don't bring jargon into your analysis. It will nearly always mislead you as most of us really are not amplifier designers. The only thing to note is class A is now banned in many countries and for a good reason. Indian ears I think has a nice post on it somewhere.

Buy what suits your system and gels with your ears. If you get a kick out of measurements sure that could be one of the things to shortlist but one really isnt sure how true the numbers really are, just like the gas mileage printed on your cars brochure, so take the numbers with a pinch of salt.

On Crown vs Nad320bee, Nad maybe the better amp for your home audio even though it was made 16+ years ago. I still have mine and use it with my tube pre from time to time.

Catch ya later.

 

[MNX]

How does cheaper Class D amplifiers like SMSL DA-9 compares to AB one's in the same price range?

 

[Decadent_Spectre]

I've never been a fan of class D, bass is tight but highs are harsher, mids are clinical, there is no warmth or emotion to the music.

If you like numbers or are into being "green" or like brighter/harsher highs,more detailed/clinical sound then you would probably prefer class D. Also if you are a HT buff you might prefer class D.

For everyone else, particularly people who love music and not numbers, class A/AB/H is much better.

 

[manojrc]

Many years ago, I did a Bel Canto Vs Forte 4A t( Class A amp) est and I liked Forte sound better though Bel Canto was a much more powerful amp.
Class D tech changed a lot since then.

 

[amrutmhatre90]

I am also thinking of changing my current XLS 1502. Am keen on purifi amplifiers but not sure how they compare with some of the class AB offerings from indian companies.

I am soon going to try one out, will post my findings soon. But for that the crown has to go

Guys

My humble opinion and I mean no disrespect to any one, and your mileage may vary.

Buy what suits your system and gels with your ears. If you get a kick out of measurements sure that could be one of the things to shortlist but one really isnt sure how true the numbers really are, just like the gas mileage printed on your cars brochure, so take the numbers with a pinch of salt.

On Crown vs Nad320bee, Nad maybe the better amp for your home audio even though it was made 16+ years ago. I still have mine and use it with my tube pre from time to time.

You are certainly right, but for an average joe it won't be possible to test both things. Someone entering this hobby won't have dealers to do testing at home. Hence one needs these small comparisons.

I've never been a fan of class D, bass is tight but highs are harsher, mids are clinical, there is no warmth or emotion to the music.

If you like numbers or are into being "green" or like brighter/harsher highs,more detailed/clinical sound then you would probably prefer class D. Also if you are a HT buff you might prefer class D.

For everyone else, particularly people who love music and not numbers, class A/AB/H is much better.

So true!!!! this is what I feel too.

 

[Decadent_Spectre]

I am soon going to try one out, will post my findings soon. But for that the crown has to go



You are certainly right, but for an average joe it won't be possible to test both things. Someone entering this hobby won't have dealers to do testing at home. Hence one needs these small comparisons.



So true!!!! this is what I feel too.

If your looking for a more economically oriented powerful amp to replace the Crown that sounds good on speakers, you could try out the QSC RMX Series.

 

[Prodigy]

Recently auditioned a Wyred 4 Sound amp and I just liked it. Think it’s the STI series. It was I would say at par with some of the highly praised Class AB amps. I think a well implemented Class D amps can very well go head on with some of the class AB’s

 

[amrutmhatre90]

If your looking for a more economically oriented powerful amp to replace the Crown that sounds good on speakers, you could try out the QSC RMX Series.

Not looking to add a class D right now, thanks
Maybe in future for center channel.

Recently auditioned a Wyred 4 Sound amp and I just liked it. Think it’s the STI series. It was I would say at par with some of the highly praised Class AB amps. I think a well implemented Class D amps can very well go head on with some of the class AB’s

Well said, but these class D amps are built from ground up for music and not DJ or party equipment. What goes into amps and its real use case matters too.
Also audiophile grade class D amps cost as much as class A/Bs foo

 

[Decadent_Spectre]

The QSC RMX is not class D, class H.

 

[raghupb]

The QSC RMX is not class D, class H.

Is Class H a variation of Class G. Separate high powered voltage rail to belt out more power.
I have a pair of Outlaw amps that use class A/B/G. A/B up to 80W and G after that
Cheers,
Raghu

 

[Decadent_Spectre]

As I recall they are similar but I don't know so much about the working of amp classes/internal design.

You could read here if you are technically minded or search Google -

https://en.wikipedia.org/wiki/Power_amplifier_classes

 

[amanupputuri]

Hello everyone,

I have been experimenting few things in my chain, trying different pre amps, power amps and new ways of listening music. Not that I am not satisfied but wanted to learn and feel how each change in a chain affected sound, in a good or bad way.

I have a Class D Crown XLS 2002 Power amp which I was using to power Q Accoustics 3050i which were connected to Denon x3700 and a FX Audio tube-03 Tube Pre Amp. This is around 375wpc at 8ohms.

I also have a NAD 320BEE Integrated Amplifier which can be used as power amplifier, I used this as a IA until now. With Class A/B at 50wpc at 8ohms.

One day, I decided to try the NAD as a power amplifier and test it with Crown XLS. Does more watts mean better? 50wpc Class A/B vs 375wpc class D.
Few wire swaps done, and started my test playlist.

Chain tested was:
1) Rpi Streamer > Tube Pre amp > NAD > Q acoustics 3050i
2) Rpi Streamer > Tube Pre amp > Crown XlS 2002 > Q acoustics 3050i

The Result:
1) Nad 320BEE Power Amp - The result was astonishing, everything felt much smoother yet punchy, I could immediately tell the bass and mids were better, highs slightly controlled. I could literally feel bass hitting my body.
I can listen to this at high volume whole day without fatigue. At low or moderate volumes, the bass is still felt.

2) Crown XLS 2002 - I was used to listening to this combo more often , the bass was tight and controlled. But it did not hit my body like the case with NAD. Has slightly sparkly highs. This chain feels more digital and one can notice the resolution is much better.
I cannot listen to this at high volumes, or it is just me. The sparkly highs are a issue for me. At low or moderate volumes the bass is still tight but cannot be felt.

Two things to point out:
1) Why the NAD 320BEE did not sound so good as a standalone Integrated amplifier? ANSWER is Pre Amp section! I had read it online multiple times the pre amp section is weak point of the NAD 320BEE. And by using and testing it as a power amplifier alone with a different pre amp it stands true.
Not that it is bad, but my whole system came alive when I added a tube Pre amp, I even tested with my Denon x3700 as pre amp and it still sounds better than using as IA.

2) Should One use Crown XLS for music? definitely yes but with caution. Your speakers shouldn't be bright but neutral or warm can do good. Crown XLS sounds too good at medium volume for music which has instruments specially Indian music. The separation, clarity and detail is amazing. And it scores high on cost to value factor.

I have made a small video comparing how both sound with A/B testing and mixing songs:

Would like to know your views if you testes both Class A/B and Class D amps in your chain, would help me understanding things better too.

I am looking to sell the Crown XLS, i am using it lesser than I used to, but this is in my listening scenario. I Also have space issues.

I like quality of class A and H amplifiers

 

[Analogous]

Here is a post from Archimago provocatively titled “ Not all amplifiers sound the same (but many do”)
He tests a class A Pass Labs SIT and a class D amp, posts measurements, analysis etc and In his summary he says:
“ "clean" amps will be indistinguishable in a volume-controlled blind test with actual music regardless of whether they're Class A or AB or D. Tube or solid-state. Lower or higher feedback.

Manufacturers love to differentiate and imply sonic differences using technical descriptions (eg. Class A, low feedback) and some audiophiles likewise might swear by them without evidence that such claims are true - or take the time to listen in a controlled environment, much less blinded!

As usual, some folks will also gravitate towards luxury products and the pride of ownership that can come with that. Yeah, tube amps can glow nicely and their physical "warmth" might accentuate the perception of sonic warmth. Likewise, big price tags and seeing an imposing 100lb behemoth amplifier in a fancy showroom may have strong psychological effects. When it comes to sound quality, let's try not to conflate "high fidelity" sound with the "non-utilitarian benefits" of luxury products.”

For the full context of these comments, read:

SUMMER MUSINGS: No... Not all amplifiers sound the same (but many do! ;-).

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[manojrc]

“ "clean" amps will be indistinguishable in a volume-controlled blind test with actual music regardless of whether they're Class A or AB or D. Tube or solid-state. Lower or higher feedback.

That's my experience too. Thanks for sharing.