Class-D sound - any comments? - Page 2

darkfenriz · 14th March 2006, 09:49 AM

He does not speak about class D amps, but power DACs. Anyone read it?

phase_accurate · 14th March 2006, 09:56 AM

He also utters the expression "digital amp" quite often which is the preferred marketing BS designation for calss-d amps.

Regards

Charles

darkfenriz · 14th March 2006, 10:03 AM

Quote:

Typical class D uses an analog waveform to modulate a switching supply, so it's technically not really digital.
(...)
The point I am making is that the amplifier is one of worst possible points to make the final digital to analog conversion.

outofthebox · 14th March 2006, 10:48 AM

It's always refreshing to hear a one sided point of view on a subject. Shows the depth and thought process of the individual.

GB Shaw had aptly remarked...

"The reasonable man adapts himself to the world (Transistors, tubes, Class A, AB?) ; the unreasonable one (Class D protagonists ?) persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man."

If I recall correctly, Bryston had also trashed E-I core transformers in favour of Toroidals in an article a few years ago.

As a sheer coincidence, my new DIY Mono block design utilises two of the very technologies which Bryston seems to hate from the core of their heart - a Modified UcD400AD utilising E-I core power transformers! I'm tempted to seek out Bryston Amps in Singapore for a Death Match!

sagarverma · 14th March 2006, 11:15 AM

class d is the best.such high effeciency,unthinkable for any other class.
no matter what a particular person says(views enmating from failure to understand such a wonderful class) , class d is the best.

SSassen · 14th March 2006, 11:51 AM

Let me share an experience with all of you that took place this weekend and illustrates very well the fact that many still think Class-D is digital by nature and hence must be inferior to a pure analog amplifier.

I was asked by the organisation of the DDIY2006 (Dutch DIY 2006) to speak at their DIY conference on the topic of Class-D amplifiers. Obviously I accepted their invitation as it is a topic that interests me very much. To gauge the level of understanding with my prospective audience I polled the Dutch audio forums asking for feedback on what people would like me to address.

About 90% of the people that responded wanted to learn more about these 'digital' amplifiers and how these 'digital' amplifiers work and whether they offer any benefits. Hence the first bullet-point on my first sheet was simply the line 'Class-D amplifiers are analog by default' (in Dutch).

The next 45-mins I explained the requirements for a class-D amp (comparator, powerstage, output filter, etc.) and why analog class-D amplifiers are not much different from traditional amps. I spiced up (literally) my presentation by running a number of live simulations with LTspice addressing some of the issues of a an all-digital approach (no feedback, etc.) and several popular analog concepts (hys. mod., phase shift mod. and the UcD mod.).

Judging from the questions that resulted after pulling the last slide from view it was obvious that for the people in the audience one thing was clear, the 'D' in Class-D does not signify 'Digital' but rather a novel approach to building amplifiers.

Best regards,

Sander Sassen
http://www.hardwareanalysis.com

Pierre · 14th March 2006, 12:25 PM

Good luck with your presentation, Sander!

tianguis · 14th March 2006, 03:11 PM

Sander:
I enjoyed the tale of your experience at DIY2006. You point up a recurring bias which I, too, have experienced regarding "digital" amps.
Having implemented an ICEpower amp (dual 250ASP's) which I've demoed a few times at shootouts with other Class D amps, I've never been able to get across the concept that almost all Class D amps are analog. This, of course, is compounded by those in the audio print industry who continue to refer to them as "digital", almost in a negative way.
(BTW, I've appreciated the NuForce sagas.

)

Regards,
Larry Welsh

cpemma · 17th March 2006, 08:05 PM

I don't follow all the science, but if my £28 T-amp supplied by a £14 SMPS block and a bit of old mains flex to the speakers sounds better than my old (and considerably more expensive) "classic" A/B system, then I'm all for this progress stuff.

And people here say I can improve on the stock quality with a few simple mods...

14th March 2006, 11:15 AM	#15
sagarverma diyAudio Member Join Date: Feb 2005 Location: NEW DELHI	class d is the best.such high effeciency,unthinkable for any other class. no matter what a particular person says(views enmating from failure to understand such a wonderful class) , class d is the best. __________________ Never Underestimate The Bandwidth of A Station Wagon Full Of Magnetic Tapes Hurtling Down The Highway...................Andrew S Tanenbaum

14th March 2006, 11:51 AM	#16
SSassen diyAudio Member Join Date: Mar 2005 Location: Purmerend	Let me share an experience with all of you that took place this weekend and illustrates very well the fact that many still think Class-D is digital by nature and hence must be inferior to a pure analog amplifier. I was asked by the organisation of the DDIY2006 (Dutch DIY 2006) to speak at their DIY conference on the topic of Class-D amplifiers. Obviously I accepted their invitation as it is a topic that interests me very much. To gauge the level of understanding with my prospective audience I polled the Dutch audio forums asking for feedback on what people would like me to address. About 90% of the people that responded wanted to learn more about these 'digital' amplifiers and how these 'digital' amplifiers work and whether they offer any benefits. Hence the first bullet-point on my first sheet was simply the line 'Class-D amplifiers are analog by default' (in Dutch). The next 45-mins I explained the requirements for a class-D amp (comparator, powerstage, output filter, etc.) and why analog class-D amplifiers are not much different from traditional amps. I spiced up (literally) my presentation by running a number of live simulations with LTspice addressing some of the issues of a an all-digital approach (no feedback, etc.) and several popular analog concepts (hys. mod., phase shift mod. and the UcD mod.). Judging from the questions that resulted after pulling the last slide from view it was obvious that for the people in the audience one thing was clear, the 'D' in Class-D does not signify 'Digital' but rather a novel approach to building amplifiers. Best regards, Sander Sassen http://www.hardwareanalysis.com __________________ Acception without proper examination equals religion Condemnation without proper examination equals prejudice

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14th March 2006, 09:49 AM	#11
darkfenriz diyAudio Member Join Date: Jun 2004 Location: Warsaw	He does not speak about class D amps, but power DACs. Anyone read it?

14th March 2006, 09:56 AM	#12
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	He also utters the expression "digital amp" quite often which is the preferred marketing BS designation for calss-d amps. Regards Charles

14th March 2006, 10:48 AM	#14
outofthebox diyAudio Member Join Date: May 2004 Location: Singapore	It's always refreshing to hear a one sided point of view on a subject. Shows the depth and thought process of the individual. GB Shaw had aptly remarked... "The reasonable man adapts himself to the world (Transistors, tubes, Class A, AB?) ; the unreasonable one (Class D protagonists ?) persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man." If I recall correctly, Bryston had also trashed E-I core transformers in favour of Toroidals in an article a few years ago. As a sheer coincidence, my new DIY Mono block design utilises two of the very technologies which Bryston seems to hate from the core of their heart - a Modified UcD400AD utilising E-I core power transformers! I'm tempted to seek out Bryston Amps in Singapore for a Death Match!

14th March 2006, 12:25 PM	#17
Pierre Banned Join Date: Nov 2004 Location: Paris	Good luck with your presentation, Sander!

14th March 2006, 03:11 PM	#18
tianguis diyAudio Member Join Date: Oct 2004	Sander: I enjoyed the tale of your experience at DIY2006. You point up a recurring bias which I, too, have experienced regarding "digital" amps. Having implemented an ICEpower amp (dual 250ASP's) which I've demoed a few times at shootouts with other Class D amps, I've never been able to get across the concept that almost all Class D amps are analog. This, of course, is compounded by those in the audio print industry who continue to refer to them as "digital", almost in a negative way. (BTW, I've appreciated the NuForce sagas. ) Regards, Larry Welsh

17th March 2006, 08:05 PM	#19
cpemma diyAudio Member Join Date: Jul 2003 Location: S Yorkshire OK	I don't follow all the science, but if my £28 T-amp supplied by a £14 SMPS block and a bit of old mains flex to the speakers sounds better than my old (and considerably more expensive) "classic" A/B system, then I'm all for this progress stuff. And people here say I can *improve* on the stock quality with a few simple mods...

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