[PRELUDE]

We had some conversation here while back about digital pre but the way I see it,the digital power amps are growing in the market quicker then we could think of.It has been a while that I am reading about them because the few audio magazines that I receive monthly they started to write about them and in every issue you can find few reviews also including the Stereophile which they had the 1000W digital Anthem review in the last issue.
The first time that I heard the digital amp was back in 1998 at High-End show in Frankfurt(Germany)and it was the TACT MILLENNIUM DIGITAL which was driving a pair of B&W.I do not remember how was the sound,all I can remember is they had a big sign on the wall inside the hotel room that said "One day all amplifiers will be digital but today is just one" and of course I had more hair on my head.
My second experience was about 6 years ago at the High-End show in Montreal and it was the B&O BEOLAB5 powered active speakers which was using 4 digital power amp in each speaker and I really like this speaker with no question asked.
So,I cannot say that I know anything about digital amp,but one think I know is they very beneficial for companies because of being high efficient and do not generate too much of heat so it can be build with less cost then solid state and nobody has to go to China any more to stay in business.
What I would like to know is,if we can ignore the style,size,brand name and some of other subjective stuff,Then what really class A/B can do that class-D cannot and why?

[G Georgopoulos]

Digital I assume is class-d, it is also solid state...

[PRELUDE]

Digital I assume is class-d, it is also solid state...

Yes class D.

[PRELUDE]

Digital I assume is class-d, it is also solid state...

You right though,my bad.

[G Georgopoulos]

If they can make it sound good, why not...

[JerryLove]

All three classes (A, B, and D) are "solid state". So are other classes like G, H, and T

Normally that term means "no moving parts", but in the audio world it separates "tube amps" and "non-tube-amps (solid state)".

Seriously: Wiki is a great source here.

Class A eats too much power and makes too much heat to be a high-power amp.
Class B is twice as efficient, but has significant distortion problems.

http://en.wikipedia.org/wiki/Electronic_amplifier#Power_amplifier_classes

Class D (and its variations like H) dominate in the car and professional amp world.
I'm not sure there's a performance-based argument against them any longer.

[Rclark]

Class D..
I'm not sure there's a performance-based argument against them any longer.

Yeah, that ship has sailed.

[firedog]

Class D isn't "digital"; the D was just the next letter available in the alphabet for an amp category. Class D are "switching" amps, but not digital amps.

http://en.wikipedia.org/wiki/Class-D_audio_amplifier :

The term "class D" is sometimes misunderstood as meaning a "digital" amplifier. While some class D amps may indeed be controlled by digital circuits, the power stage deals with voltage and current as a function of time. The smallest amount of noise, timing uncertainty, voltage ripple or any other non-ideality immediately results in an irreversible change of the output signal. The same errors will only lead to incorrect results when they become so large that a signal representing a digit is distorted beyond recognition. Up to that point, non-idealities have no impact on the transmitted signal. The difference between digital and analogue signals is that digital signals are subsequently interpreted as numbers whereas in analogue signals the exact waveform matters.

If you want a true digital amp you need to look at something like the new NAD amps, some of which are "true digital" PWM amps (The signal path has no digital filter, no DAC, no analog gain stages, no analog volume control, no preamplifier, and no interconnects.)

As a class D owner, I'd say that they can be very good amps, but probably still fall slightly short of the very best A/B amps in the extremely  high frequency  reproduction.  But they are truly audiophile amps these days, and can be relative bargains.

[Rclark]

If I'm not mistaken however, Firedog, you've only heard the "Class D" brand amps, and not the latest from Hypex. I haven't listened to those amps together, but others like Poseidonsvoice owns both, and says the Ncores are a considerable step up, so that isn't the case any longer (High freq, or any other problems).

[amuser]

Haven't heard the Ncores separates  but class D sounds very Hifi.  IOWs they are like what you hear from a mid priced receiver n terms of a generic hi fi playback sound. But a step up in bass.

A good class a/b with a nice tube pre can make a Marshall stack sound like its right in your house.

I have heard some really decent Class D in micromega (which happen to be ncore amps). They are quite nice and certainly have a sound worth buying into. But they still sound hi fi.

[Rclark]

I just looked at Micromega (never, ever heard of them), and they certainly are not using Ncore modules. You can tell merely by the specs that they are not NC1200 based amps. UCD, possibly, which, no, is not the Ncore. You are confused. The Ncores are absolutely fabulous, if you ever do genuinely get to hear some, I think you will be very surprised. The old cliche's are now just that, cliche's.

.. I just looked at the photo's of their amps and it clearly says UCD. So yes, you heard Hypex amps, no, you didn't listen to the Ncore. The old UCD's are not in the same league.

[lowtech]

The old UCD's are not in the same league.

And you base this on what?

[Rclark]

.. are you serious?

[lowtech]

It's a very simple question.  Do  you have an answer?

[Rclark]

Bruno said. Good enough?

[firedog]

If I'm not mistaken however, Firedog, you've only heard the "Class D" brand amps, and not the latest from Hypex. I haven't listened to those amps together, but others like Poseidonsvoice owns both, and says the Ncores are a considerable step up, so that isn't the case any longer (High freq, or any other problems).

Not trying to get into an argument about this; just trying to point out that lots of audiophiles, including those who have heard the NCore, think they are lacking in that last bit of high frequency that distinguishes the best A/B amps.  So this isn't a settled question yet.

[Rclark]

Simply isn't true. I've read all the reviews. The very few that had some issues, were resolved with some component changes, in other words, it wasn't the amp. The amp itself doesn't have any issues whatsoever in high frequency reproduction.

I know you have some reservations, go talk to Anand, who owns both. Says the diff between the ClassD and the Ncores is huge, not even close.

[rollo]

Like everything else it depends on the design. there are several manufactures of "D" amps.  Some use B&O modules. Others do not. The Arions are a hybrid  design using a 6H30 input tube. The modules are designed and built in house. The switching power supply as well is deigned in house.
   IMO a general statement cannot be valid. Only A to B comparisons will tell the story. They are getting better everyday. What I like the most is no need for NOS tubes at crazy prices. For years our 211 based amps delivered wonderful sonics however the class "D" amps now are residing in our system.
     Before one dismisses class "D" do an A to B and then make your decision.  I never thought we would prefer a class "D" over our beloved tubed amps.
      Yes we are dealers for Arion.



charles



charles


   

[Rclark]

Trung is really hot for those Arion amps...

And I believe the first room Pez and Tyson described at RMAF was this one

http://www.audiocircle.com/index.php?topic=110562.0

And they really loved the sound of the Arion's with the panel speakers. Trung was determined that I should buy those amps instead, but I'd never heard them, or even heard of them, and my mind was set.

Amps are now the finest, highest spec devices in my system, I hope to one day wring them out by eventually having the rest of my chain be as close to as good as they are.

[Jon L]

Haven't heard the Ncores separates  but class D sounds very Hifi.  IOWs they are like what you hear from a mid priced receiver n terms of a generic hi fi playback sound. But a step up in bass.

A good class a/b with a nice tube pre can make a Marshall stack sound like its right in your house.

While I have listened to my share of rather disappointing class-D amps in past, given how short their serious development has been compared to traditional class A/AB amps, they certainly hold lots of promise, starting to be revealed in the NCores of late. 

A good class D with a nice tube pre, as you state for A/B, can really sing IME