Graham Holloway schreef:
"Arny Krueger" wrote in message
. ..
"max graff" wrote in message
oups.com
Hi guys,

Pardon my lack of technical lingo but Rotel and a few
other companies have been flaunting class D power amps.
I know that class A is the best in amplification
Class AB done right is just as good, if not better.

however attaining that level at higher wattage is only
hypothetical.
Not to mention stupid.

I want to know what and how good is the supposed class D
amplification.
Current implementations seem to underperform its potential.

The biggest problem with switchmode operation letely has been keeping the
switching pulses out of the speakers. Running the switches faster is the
obvious solution, as it is easier and more practical to build high powered
filters, as the frequency being filtered out goes up.

Right now a lot of class D amplifiers seem to suffer from excessively high
output impedance near the top of the audio range.


That's probably due to the aforesaid filter.

Graham H



Make that certainly.

It's a public secret there's only a small market for better sounding
equipment. Most people don't bother because they want to hear amplified
sound and do not enjoy the quality, especially when expensive. There
lays the problem manufacturers are facing.

On Sun, 13 May 2007 17:11:14 +0200, jaap wrote:

Graham Holloway schreef:
"Arny Krueger" wrote in message
. ..
"max graff" wrote in message
oups.com
Hi guys,

Pardon my lack of technical lingo but Rotel and a few
other companies have been flaunting class D power amps.
I know that class A is the best in amplification
Class AB done right is just as good, if not better.

however attaining that level at higher wattage is only
hypothetical.
Not to mention stupid.

I want to know what and how good is the supposed class D
amplification.
Current implementations seem to underperform its potential.

The biggest problem with switchmode operation letely has been keeping the
switching pulses out of the speakers. Running the switches faster is the
obvious solution, as it is easier and more practical to build high powered
filters, as the frequency being filtered out goes up.

Right now a lot of class D amplifiers seem to suffer from excessively high
output impedance near the top of the audio range.


That's probably due to the aforesaid filter.

Graham H



Make that certainly.

It's a public secret there's only a small market for better sounding
equipment. Most people don't bother because they want to hear amplified
sound and do not enjoy the quality, especially when expensive. There
lays the problem manufacturers are facing.

I think that lost something in the translation from Dutch. Could you
elaborate?

d

--
Pearce Consulting
http://www.pearce.uk.com

jaap wrote:
honestguvnor schreef:
On May 11, 10:07 pm, max graff wrote:
I know that class A is the best in amplification however attaining
that level at higher wattage is only hypothetical.

This is not a wise statement. I am sure you will find quite a few
readers prepared to bet you cannot hear the difference between a
reasonable class A amplifier and a reasonable class AB driving a
reasonable loudspeaker.

I want to know what and how good is the supposed class D
amplification.

This is a good question (assuming "digital" amplifier of whatever
class and audibly neutral under normal conditions) . I do not know the
answer and given the absence of any reliable consumer audio
publications and the absence of reasonable specifications from the
manufacturers it is not obvious to me where to look for an answer.

Obviously one could perform experiments oneself but that would imply a
pretty awesome loss of basic technical knowledge about the performance
of consumer audio in these broadband www days.

Anyone?


Just an opinion: history shows that despite 'progress' amplification
quality diminishes every decade. Don't believe you can't do without this
new class. A good system dating from 1960 or 1970 or 1980 will beat any
plastic rubbish -whatever class- dating from 2007.

Interesting opinion, but what is it based on? Modern systems are louder,
distort less, have wider bandwidth and less noise than 1960s or 1970s
systems, but haven't improved to any great extent since the '80s.
However, they certainly haven't diminished.



The other day I demonstrated a nice turntable setup to someone who had
listened solely to digital audio. She was surprised by the reality
coming from old gear, despite S/N THD and whatever cyphers modern stuff
tries to sell to the public.

Of course old gear is capable of sounding good, but so is modern gear,
and for relatively much less money, size, power consumption and improved
reliability.

S.
--
http://audiopages.googlepages.com

Serge Auckland wrote:
jaap wrote:
honestguvnor schreef:
On May 11, 10:07 pm, max graff wrote:
I know that class A is the best in amplification however attaining
that level at higher wattage is only hypothetical.

This is not a wise statement. I am sure you will find quite a few
readers prepared to bet you cannot hear the difference between a
reasonable class A amplifier and a reasonable class AB driving a
reasonable loudspeaker.

I want to know what and how good is the supposed class D
amplification.

This is a good question (assuming "digital" amplifier of whatever
class and audibly neutral under normal conditions) . I do not know the
answer and given the absence of any reliable consumer audio
publications and the absence of reasonable specifications from the
manufacturers it is not obvious to me where to look for an answer.

Obviously one could perform experiments oneself but that would imply a
pretty awesome loss of basic technical knowledge about the performance
of consumer audio in these broadband www days.

Anyone?


Just an opinion: history shows that despite 'progress' amplification
quality diminishes every decade. Don't believe you can't do without
this new class. A good system dating from 1960 or 1970 or 1980 will
beat any plastic rubbish -whatever class- dating from 2007.

Interesting opinion, but what is it based on? Modern systems are louder,
distort less, have wider bandwidth and less noise than 1960s or 1970s
systems, but haven't improved to any great extent since the '80s.
However, they certainly haven't diminished.



The other day I demonstrated a nice turntable setup to someone who had
listened solely to digital audio. She was surprised by the reality
coming from old gear, despite S/N THD and whatever cyphers modern
stuff tries to sell to the public.

Of course old gear is capable of sounding good, but so is modern gear,
and for relatively much less money, size, power consumption and improved
reliability.

S.

Hi Serge,

My opinion is based on human hearing and not on the momentary
technological approach from a-musical tecchies. I got to this opinion
speaking with fellow musiclovers, who share a passion for the best
obtainable. Most got tube amps under 5W per channel, some built their
own, often accomplished by single driver speakers.

Modern equipment is expensive compared to good used quality parts. The
latter will probably outlast the former by decades because of the poor
quality parts used these days.
Agreed, ancient low budget equipment belongs on the scrapyard.

Jaap

Don Pearce schreef:
On Sun, 13 May 2007 17:11:14 +0200, jaap wrote:

Graham Holloway schreef:
"Arny Krueger" wrote in message
. ..
"max graff" wrote in message
oups.com
Hi guys,

Pardon my lack of technical lingo but Rotel and a few
other companies have been flaunting class D power amps.
I know that class A is the best in amplification
Class AB done right is just as good, if not better.

however attaining that level at higher wattage is only
hypothetical.
Not to mention stupid.

I want to know what and how good is the supposed class D
amplification.
Current implementations seem to underperform its potential.

The biggest problem with switchmode operation letely has been keeping the
switching pulses out of the speakers. Running the switches faster is the
obvious solution, as it is easier and more practical to build high powered
filters, as the frequency being filtered out goes up.

Right now a lot of class D amplifiers seem to suffer from excessively high
output impedance near the top of the audio range.


That's probably due to the aforesaid filter.

Graham H


Make that certainly.

It's a public secret there's only a small market for better sounding
equipment. Most people don't bother because they want to hear amplified
sound and do not enjoy the quality, especially when expensive. There
lays the problem manufacturers are facing.

I think that lost something in the translation from Dutch. Could you
elaborate?

d


Alright. Being a public secret is a saying (over here) and means as much
as being common knowledge to most people.

jaap wrote:
Serge Auckland wrote:
jaap wrote:
honestguvnor schreef:
On May 11, 10:07 pm, max graff wrote:
I know that class A is the best in amplification however attaining
that level at higher wattage is only hypothetical.

This is not a wise statement. I am sure you will find quite a few
readers prepared to bet you cannot hear the difference between a
reasonable class A amplifier and a reasonable class AB driving a
reasonable loudspeaker.

I want to know what and how good is the supposed class D
amplification.

This is a good question (assuming "digital" amplifier of whatever
class and audibly neutral under normal conditions) . I do not know the
answer and given the absence of any reliable consumer audio
publications and the absence of reasonable specifications from the
manufacturers it is not obvious to me where to look for an answer.

Obviously one could perform experiments oneself but that would imply a
pretty awesome loss of basic technical knowledge about the performance
of consumer audio in these broadband www days.

Anyone?


Just an opinion: history shows that despite 'progress' amplification
quality diminishes every decade. Don't believe you can't do without
this new class. A good system dating from 1960 or 1970 or 1980 will
beat any plastic rubbish -whatever class- dating from 2007.

Interesting opinion, but what is it based on? Modern systems are
louder, distort less, have wider bandwidth and less noise than 1960s
or 1970s systems, but haven't improved to any great extent since the
'80s. However, they certainly haven't diminished.



The other day I demonstrated a nice turntable setup to someone who
had listened solely to digital audio. She was surprised by the
reality coming from old gear, despite S/N THD and whatever cyphers
modern stuff tries to sell to the public.

Of course old gear is capable of sounding good, but so is modern gear,
and for relatively much less money, size, power consumption and
improved reliability.

S.

Hi Serge,

My opinion is based on human hearing and not on the momentary
technological approach from a-musical tecchies. I got to this opinion
speaking with fellow musiclovers, who share a passion for the best
obtainable. Most got tube amps under 5W per channel, some built their
own, often accomplished by single driver speakers.

So they're not into high fidelity ;-)


Modern equipment is expensive compared to good used quality parts. The
latter will probably outlast the former by decades because of the poor
quality parts used these days.
Agreed, ancient low budget equipment belongs on the scrapyard.

Jaap

New equipment can cost more than used, although some of the prices being
paid for old technologies like SETs and paper-coned full-range drivers
are a lot higher than you can buy perfectly decent modern stuff for.
However, if you compare what an amplifier costs now and what a similar
spec cost in 1960 or 1970, it's an awful lot cheaper now.

Many of us, me included, like vintage gear, in the same way I like
vintage cars, fountain pens and mechanical watches, but I don't expect
(or get) the same standard of performance as I do from my modern stuff.

S.




--
http://audiopages.googlepages.com

On Sun, 13 May 2007 17:53:45 +0200, jaap wrote:

Don Pearce schreef:
On Sun, 13 May 2007 17:11:14 +0200, jaap wrote:

Graham Holloway schreef:
"Arny Krueger" wrote in message
. ..
"max graff" wrote in message
oups.com
Hi guys,

Pardon my lack of technical lingo but Rotel and a few
other companies have been flaunting class D power amps.
I know that class A is the best in amplification
Class AB done right is just as good, if not better.

however attaining that level at higher wattage is only
hypothetical.
Not to mention stupid.

I want to know what and how good is the supposed class D
amplification.
Current implementations seem to underperform its potential.

The biggest problem with switchmode operation letely has been keeping the
switching pulses out of the speakers. Running the switches faster is the
obvious solution, as it is easier and more practical to build high powered
filters, as the frequency being filtered out goes up.

Right now a lot of class D amplifiers seem to suffer from excessively high
output impedance near the top of the audio range.


That's probably due to the aforesaid filter.

Graham H


Make that certainly.

It's a public secret there's only a small market for better sounding
equipment. Most people don't bother because they want to hear amplified
sound and do not enjoy the quality, especially when expensive. There
lays the problem manufacturers are facing.

I think that lost something in the translation from Dutch. Could you
elaborate?

d


Alright. Being a public secret is a saying (over here) and means as much
as being common knowledge to most people.

No, I got that bit - it was all the rest that had me puzzled.

d

--
Pearce Consulting
http://www.pearce.uk.com

Serge Auckland wrote:
jaap wrote:
Serge Auckland wrote:
jaap wrote:
honestguvnor schreef:
On May 11, 10:07 pm, max graff wrote:
I know that class A is the best in amplification however attaining
that level at higher wattage is only hypothetical.

This is not a wise statement. I am sure you will find quite a few
readers prepared to bet you cannot hear the difference between a
reasonable class A amplifier and a reasonable class AB driving a
reasonable loudspeaker.

I want to know what and how good is the supposed class D
amplification.

This is a good question (assuming "digital" amplifier of whatever
class and audibly neutral under normal conditions) . I do not know the
answer and given the absence of any reliable consumer audio
publications and the absence of reasonable specifications from the
manufacturers it is not obvious to me where to look for an answer.

Obviously one could perform experiments oneself but that would imply a
pretty awesome loss of basic technical knowledge about the performance
of consumer audio in these broadband www days.

Anyone?


Just an opinion: history shows that despite 'progress' amplification
quality diminishes every decade. Don't believe you can't do without
this new class. A good system dating from 1960 or 1970 or 1980 will
beat any plastic rubbish -whatever class- dating from 2007.

Interesting opinion, but what is it based on? Modern systems are
louder, distort less, have wider bandwidth and less noise than 1960s
or 1970s systems, but haven't improved to any great extent since the
'80s. However, they certainly haven't diminished.



The other day I demonstrated a nice turntable setup to someone who
had listened solely to digital audio. She was surprised by the
reality coming from old gear, despite S/N THD and whatever cyphers
modern stuff tries to sell to the public.

Of course old gear is capable of sounding good, but so is modern
gear, and for relatively much less money, size, power consumption and
improved reliability.

S.

Hi Serge,

My opinion is based on human hearing and not on the momentary
technological approach from a-musical tecchies. I got to this opinion
speaking with fellow musiclovers, who share a passion for the best
obtainable. Most got tube amps under 5W per channel, some built their
own, often accomplished by single driver speakers.

So they're not into high fidelity ;-)


Modern equipment is expensive compared to good used quality parts. The
latter will probably outlast the former by decades because of the poor
quality parts used these days.
Agreed, ancient low budget equipment belongs on the scrapyard.

Jaap

New equipment can cost more than used, although some of the prices being
paid for old technologies like SETs and paper-coned full-range drivers
are a lot higher than you can buy perfectly decent modern stuff for.
However, if you compare what an amplifier costs now and what a similar
spec cost in 1960 or 1970, it's an awful lot cheaper now.

Many of us, me included, like vintage gear, in the same way I like
vintage cars, fountain pens and mechanical watches, but I don't expect
(or get) the same standard of performance as I do from my modern stuff.

S.


I might be wrong but is 'HiFi' not invented as a marketing trick? I
recall a hip 1958 ad from Philips for that years new models table radios

What's your standard of performance? Reading a 100Mhz scope?
My standard is about music with as little as possible interference,
whatever technology, cosmetics, cyphers, brand or anything.

Jaap

Don Pearce wrote:
On Sun, 13 May 2007 17:53:45 +0200, jaap wrote:

Don Pearce schreef:
On Sun, 13 May 2007 17:11:14 +0200, jaap wrote:

Graham Holloway schreef:
"Arny Krueger" wrote in message
. ..
"max graff" wrote in message
oups.com
Hi guys,

Pardon my lack of technical lingo but Rotel and a few
other companies have been flaunting class D power amps.
I know that class A is the best in amplification
Class AB done right is just as good, if not better.

however attaining that level at higher wattage is only
hypothetical.
Not to mention stupid.

I want to know what and how good is the supposed class D
amplification.
Current implementations seem to underperform its potential.

The biggest problem with switchmode operation letely has been keeping the
switching pulses out of the speakers. Running the switches faster is the
obvious solution, as it is easier and more practical to build high powered
filters, as the frequency being filtered out goes up.

Right now a lot of class D amplifiers seem to suffer from excessively high
output impedance near the top of the audio range.


That's probably due to the aforesaid filter.

Graham H


Make that certainly.

It's a public secret there's only a small market for better sounding
equipment. Most people don't bother because they want to hear amplified
sound and do not enjoy the quality, especially when expensive. There
lays the problem manufacturers are facing.

I think that lost something in the translation from Dutch. Could you
elaborate?

d

Alright. Being a public secret is a saying (over here) and means as much
as being common knowledge to most people.

No, I got that bit - it was all the rest that had me puzzled.

d


Look around you, probably within your family or among your friends. Most
people won't be bothered by new disk standards, color of face plates,
brand names, fourfold wiring with precious metals, quantity of
loudspeakers etcetera. It's all about enjoying the music, not how it is
reproduced.
OK, there exist a group of people running to the shop every year for the
last model but I don't think this is because they enjoy the music so
much. See my point?

Another example: TV sets. It's only for a couple of years manufacturers
are paying attention to better sound reproduction. Many of us are having
terrible reproduction quality and still enjoy the moving pictures.

Manufacturers can produce better sets but what happens if customers
don't want to spend more money on a TV or HiFi?

Jaap

On Sun, 13 May 2007 19:37:01 +0200, jaap wrote:

It's a public secret there's only a small market for better sounding
equipment. Most people don't bother because they want to hear amplified
sound and do not enjoy the quality, especially when expensive. There
lays the problem manufacturers are facing.

I think that lost something in the translation from Dutch. Could you
elaborate?

d

Alright. Being a public secret is a saying (over here) and means as much
as being common knowledge to most people.

No, I got that bit - it was all the rest that had me puzzled.

d


Look around you, probably within your family or among your friends. Most
people won't be bothered by new disk standards, color of face plates,
brand names, fourfold wiring with precious metals, quantity of
loudspeakers etcetera. It's all about enjoying the music, not how it is
reproduced.
OK, there exist a group of people running to the shop every year for the
last model but I don't think this is because they enjoy the music so
much. See my point?


Yes, but what did you mean when you said that people want to hear
amplified sound and do not enjoy the quality?

Another example: TV sets. It's only for a couple of years manufacturers
are paying attention to better sound reproduction. Many of us are having
terrible reproduction quality and still enjoy the moving pictures.


I shouldn't think many of us on this group use the sound system
supplied with a TV.

Manufacturers can produce better sets but what happens if customers
don't want to spend more money on a TV or HiFi?

Jaap

Nobody has produced anything better for many years. Quality plateaued
once the initial reproduction problems with CD had been understood and
addressed. Hi Fi is now a lifestyle business, and quite unrelated to
sound reproduction.

But do remember the nature of the group you are addressing here. We
are mostly not Hi Fi fashion victims, and many of us are well able to
understand in great detail what the true situation is.

d

--
Pearce Consulting
http://www.pearce.uk.com