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how good are class D amplifiers?



 
 
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  #91 (permalink)  
Old May 15th 07, 12:12 PM posted to uk.rec.audio
Serge Auckland
external usenet poster
 
Posts: 104
Default how good are class D amplifiers?

Arny Krueger wrote:
"Keith G" wrote in message


"Arny Krueger" wrote in message
. ..


"Keith G" wrote in message


"jaap" wrote


As for the orchestra which is in need of 10 or more
watts to be reproduced correctly, this is again a
(1970) sales story. Right now I am listening through a
1.5 watt amplifier giving me more than enough
decibells to feed the 4x6 meter room. Hardrock or
orchestra, no problem. The problem is with the
loudspeakers, not having made serious progress since
1960.


I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!


No prejudice there.


Yours or mine....??


Good question. The claim that a 10 watt amp sounds louder and cleaner than a
100 watt amp only makes sense if there is something very wrong with the 100
watt amp. When it turns out that the reliably-audible defects tend to
cluster around the 10 watt amp, then doesn't the person making the claim
become suspect?


Knowing Keith's equipment, it comes as no surprise:-

His horns have a sensitivity of about 100dB/watt, so his 8 watts will
provide a level of around 109dB.

His IMFs have a sensitivity of around 84dB/watt, so his 100 watt
amplifier will provide a level of around 104dB.

So, his 8 watt valve set-up will sound louder. This is before any
subjective loudness increase caused by higher distortion in the valve
set-up.

Keith made no claims as to which sound better (at least not in this
thread) only loudness.

S.
--
http://audiopages.googlepages.com
  #92 (permalink)  
Old May 15th 07, 12:13 PM posted to uk.rec.audio
Arny Krueger
external usenet poster
 
Posts: 3,850
Default how good are class D amplifiers?

"Keith G" wrote in message

"Arny Krueger" wrote in message
. ..
"Keith G" wrote in message


"Arny Krueger" wrote in message
. ..


"Keith G" wrote in message


"jaap" wrote


As for the orchestra which is in need of 10 or more
watts to be reproduced correctly, this is again a
(1970) sales story. Right now I am listening through
a 1.5 watt amplifier giving me more than enough
decibells to feed the 4x6 meter room. Hardrock or
orchestra, no problem. The problem is with the
loudspeakers, not having made serious progress since
1960.


I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!


No prejudice there.


Yours or mine....??


Good question. The claim that a 10 watt amp sounds
louder and cleaner



Cleaner? Who said anything about that? (Interesting litle
'pop-up', that one...)


than a
100 watt amp only makes sense if there is something very
wrong with the 100 watt amp. When it turns out that the
reliably-audible defects tend to cluster around the 10
watt amp, then doesn't the person making the claim
become suspect?


Not nearly as suspect as someone who can make those
suppositions on kit he doesn't know/hasn't heard -
*reeks* of prejudice that does, but I guess the speakers'
sensitivity figures flew over your head, as they did
Plowie....



Following your own self-contradictory illogic Keith, why would your claimed
sensitivity numbers be meaningful at all to me, given that I haven't heard
them?



  #93 (permalink)  
Old May 15th 07, 12:14 PM posted to uk.rec.audio
Keith G
external usenet poster
 
Posts: 7,388
Default how good are class D amplifiers?


"Laurence Payne" lpayne1NOSPAM@dslDOTpipexDOTcom wrote in message
...
On Tue, 15 May 2007 07:36:09 -0400, "Arny Krueger"
wrote:


I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!


No prejudice there.


Yours or mine....??


Good question. The claim that a 10 watt amp sounds louder and cleaner than
a
100 watt amp only makes sense if there is something very wrong with the
100
watt amp. When it turns out that the reliably-audible defects tend to
cluster around the 10 watt amp, then doesn't the person making the claim
become suspect?


Why shouldn't a 10W amp into an efficient speaker sound as loud as a
100W amp into a less efficient one? And, quite independently, why
shouldn't one pair sound better than the other?

The fault comes in when you invent the wrong reasons for one sounding
better.



Quite....



  #94 (permalink)  
Old May 15th 07, 12:26 PM posted to uk.rec.audio
Keith G
external usenet poster
 
Posts: 7,388
Default how good are class D amplifiers?


"Arny Krueger" wrote in message
. ..
"Laurence Payne" lpayne1NOSPAM@dslDOTpipexDOTcom wrote in
message

On Tue, 15 May 2007 07:36:09 -0400, "Arny Krueger"
wrote:


I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!


No prejudice there.


Yours or mine....??


Good question. The claim that a 10 watt amp sounds
louder and cleaner than a 100 watt amp only makes sense
if there is something very wrong with the 100 watt amp.
When it turns out that the reliably-audible defects tend
to cluster around the 10 watt amp, then doesn't the
person making the claim become suspect?


Why shouldn't a 10W amp into an efficient speaker sound
as loud as a 100W amp into a less efficient one?


Why would anybody in their right mind present this as a fair comparison
of amplifiers?




Who did?



But all that amplifier weirdness aside, the high efficiency speaker can
only have equivalent bandpass if it is vastly larger.



Who said anything about 'bandpass'?



Why would anybody in their right mind present that as a fair comparison
of speakers?



Who said it was?



I've got it - let us make a big fuss over the fact that a 7 liter Cobra is
faster than a 35 cc motorbike. Obvious proof that 1970s technology is
superior, right? ;-)




And you've got the brass arse to call me 'illogical'...??

(I guess it must be ****ing with rain in Merkin Land as well....)



  #95 (permalink)  
Old May 15th 07, 12:31 PM posted to uk.rec.audio
Laurence Payne
external usenet poster
 
Posts: 522
Default how good are class D amplifiers?

On Tue, 15 May 2007 12:52:01 +0100, "Keith G"
wrote:

Not used it before? Wot TF's this then:

http://www.apah69.dsl.pipex.com/

Scotch Mist?

(Can't believe you haven't seen any of the 10,000 - no, make that 20,000
links to that site I've posted over the last few years!)

Anyway, I've actually managed to get 'up there' since I posted but I still
can't see any files or folders yet! (I'm now wondering if the server site is
down - wouldn't be surprised, knowing Pipex!!)


It seems to be there. A page of hi-fi, a page of bikes, a page of
odds-and-sods and one of MP3s. Is that what there should be?

What's the latest recording? Seems a bit cruel leaving those early
attempts up there - over-close miking with lots of key noise and (dare
one say?) not very good performances. That's where we all started, but
I'm sure both recordist and musician have listened, learned and
progressed since then. You certainly seem to have enough recording
gear!
  #96 (permalink)  
Old May 15th 07, 12:32 PM posted to uk.rec.audio
Keith G
external usenet poster
 
Posts: 7,388
Default how good are class D amplifiers?


"Arny Krueger" wrote in message
. ..
"Keith G" wrote in message

"Arny Krueger" wrote in message
. ..
"Keith G" wrote in message


"Arny Krueger" wrote in message
. ..

"Keith G" wrote in message


"jaap" wrote

As for the orchestra which is in need of 10 or more
watts to be reproduced correctly, this is again a
(1970) sales story. Right now I am listening through
a 1.5 watt amplifier giving me more than enough
decibells to feed the 4x6 meter room. Hardrock or
orchestra, no problem. The problem is with the
loudspeakers, not having made serious progress since
1960.

I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!

No prejudice there.

Yours or mine....??

Good question. The claim that a 10 watt amp sounds
louder and cleaner



Cleaner? Who said anything about that? (Interesting litle
'pop-up', that one...)


than a
100 watt amp only makes sense if there is something very
wrong with the 100 watt amp. When it turns out that the
reliably-audible defects tend to cluster around the 10
watt amp, then doesn't the person making the claim
become suspect?


Not nearly as suspect as someone who can make those
suppositions on kit he doesn't know/hasn't heard -
*reeks* of prejudice that does, but I guess the speakers'
sensitivity figures flew over your head, as they did
Plowie....



Following your own self-contradictory illogic Keith, why would your
claimed sensitivity numbers be meaningful at all to me, given that I
haven't heard them?




Steady on, squire - you'll have the Plowborg round your ears, going on about
your lack of knowledge of electronics and/or banging on about the Laws Of
Physics....

....except that he'll probably append that to one my posts, if he follows his
usual, twisty form....



  #97 (permalink)  
Old May 15th 07, 12:35 PM posted to uk.rec.audio
Arny Krueger
external usenet poster
 
Posts: 3,850
Default how good are class D amplifiers?

"Serge Auckland" wrote in
message
Arny Krueger wrote:
"Keith G" wrote in message


"Arny Krueger" wrote in message
. ..


"Keith G" wrote in message


"jaap" wrote


As for the orchestra which is in need of 10 or more
watts to be reproduced correctly, this is again a
(1970) sales story. Right now I am listening through
a 1.5 watt amplifier giving me more than enough
decibells to feed the 4x6 meter room. Hardrock or
orchestra, no problem. The problem is with the
loudspeakers, not having made serious progress since
1960.


I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!


No prejudice there.


Yours or mine....??


Good question. The claim that a 10 watt amp sounds
louder and cleaner than a 100 watt amp only makes sense
if there is something very wrong with the 100 watt amp.
When it turns out that the reliably-audible defects tend
to cluster around the 10 watt amp, then doesn't the
person making the claim become suspect?


Knowing Keith's equipment, it comes as no surprise:-


His horns have a sensitivity of about 100dB/watt, so his
8 watts will provide a level of around 109dB.


Not including likely restrictions in bandwidth, that cause the sound to be
weighted towards the frequency ranges where the ear is most sensitive. I

His IMFs have a sensitivity of around 84dB/watt, so his
100 watt amplifier will provide a level of around 104dB.


The purported 5 dB difference is probably mostly just a numbers thing.

So, his 8 watt valve set-up will sound louder. This is
before any subjective loudness increase caused by higher
distortion in the valve set-up.


Yes, the 8 wall valve setup is not likely to be a paragon of undistorted,
pure sound.

Keith made no claims as to which sound better (at least
not in this thread) only loudness.


Speaking of loud horn-loaded narrowband systems, what about Keith just
cutting to the chase and buying a surplus fire siren?


  #98 (permalink)  
Old May 15th 07, 12:45 PM posted to uk.rec.audio
Nick Gorham
external usenet poster
 
Posts: 851
Default how good are class D amplifiers?

Keith G wrote:

"Dave Plowman (News)" wrote


If you can't actually hear the

difference in quality between the first and last tracks on this sort
of LP




Yeah...??


load them into your computer and look at them on a spectrum analyser.





You *are* kidding - right...???


It's

quite revealing.




That certainly was (wot new?), but forget that stupidity and tell me
what is the correct Pipex 'hostname' and what 'username' it expects for
ftp transfers to my website - I've tried all the likely candidates and
it ain't having none of it...??


Have a look on your pipex pages, I have left pipex now, so I can't tell
you what they should be. It will be something like

address: dslftp.dsl.pipex.net
username: your pipex username
password: your pipex password

--
Nick
  #99 (permalink)  
Old May 15th 07, 12:46 PM posted to uk.rec.audio
Keith G
external usenet poster
 
Posts: 7,388
Default how good are class D amplifiers?


"Serge Auckland" wrote in message
...
Arny Krueger wrote:
"Keith G" wrote in message


"Arny Krueger" wrote in message
. ..


"Keith G" wrote in message


"jaap" wrote


As for the orchestra which is in need of 10 or more
watts to be reproduced correctly, this is again a
(1970) sales story. Right now I am listening through a
1.5 watt amplifier giving me more than enough
decibells to feed the 4x6 meter room. Hardrock or
orchestra, no problem. The problem is with the
loudspeakers, not having made serious progress since
1960.


I run two parallel systems: 100 SS Watts into 82 (84?)
dB speakers and 8 or 9 valve Watts into high 90s
speaker - the valve setup blows the other one away on
the *loudness* front!!


No prejudice there.


Yours or mine....??


Good question. The claim that a 10 watt amp sounds louder and cleaner
than a 100 watt amp only makes sense if there is something very wrong
with the 100 watt amp. When it turns out that the reliably-audible
defects tend to cluster around the 10 watt amp, then doesn't the person
making the claim become suspect?

Knowing Keith's equipment, it comes as no surprise:-

His horns have a sensitivity of about 100dB/watt, so his 8 watts will
provide a level of around 109dB.

His IMFs have a sensitivity of around 84dB/watt, so his 100 watt amplifier
will provide a level of around 104dB.

So, his 8 watt valve set-up will sound louder. This is before any
subjective loudness increase caused by higher distortion in the valve
set-up.

Keith made no claims as to which sound better (at least not in this
thread) only loudness.




Correct.

Asitappens, I've made no comments on comparative sound 'quality' between
these two systems elsewhere, either - they are quite different and I like
them both. The only thing I will say is I don't like the horns on the SS
amps....

(Which is probably why a lot of people say they don't like horns - if
they've not heard them with valves, or triodes in particular??)






  #100 (permalink)  
Old May 15th 07, 01:05 PM posted to uk.rec.audio
Keith G
external usenet poster
 
Posts: 7,388
Default how good are class D amplifiers?


"Laurence Payne" lpayne1NOSPAM@dslDOTpipexDOTcom wrote in message
...
On Tue, 15 May 2007 12:52:01 +0100, "Keith G"
wrote:

Not used it before? Wot TF's this then:

http://www.apah69.dsl.pipex.com/

Scotch Mist?

(Can't believe you haven't seen any of the 10,000 - no, make that 20,000
links to that site I've posted over the last few years!)

Anyway, I've actually managed to get 'up there' since I posted but I still
can't see any files or folders yet! (I'm now wondering if the server site
is
down - wouldn't be surprised, knowing Pipex!!)


It seems to be there. A page of hi-fi, a page of bikes, a page of
odds-and-sods and one of MP3s. Is that what there should be?




Yes, the site's OK but I can't access it yet!



What's the latest recording? Seems a bit cruel leaving those early
attempts up there - over-close miking with lots of key noise and (dare
one say?) not very good performances. That's where we all started, but
I'm sure both recordist and musician have listened, learned and
progressed since then. You certainly seem to have enough recording
gear!



The problem for both of us is lack of continuity due to lack of opportunity
atm. Those recordings are virtually all *first takes* for both of us - Swim
is rusty by about 10 years on the clart and over 20 years on the piano (or
was) and I'm new to recording anyway, so it's a series of 'Square One'
starts atm and there hasn't been anything newer to replace those early
attempts yet.

There's no rush, it'll sort in time...


 




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