New Posts New Posts RSS Feed - Views On Class D Amps?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Welcome to the Graham Slee Audio Products Owners Forum

 

Open to all owners plus those contemplating the purchase of a Graham Slee HiFi System Components audio product and wishing to use this forum's loaner program: join here (Rules on posting can be found here)

This website along with trade marks Graham Slee and HiFi System Components are owned by Cadman Enterprises Ltd

Views On Class D Amps?
 Post Reply Post Reply Page  <123>
Author
  Topic Search Topic Search  Topic Options Topic Options
XTRProf View Drop Down
New Member
New Member


Joined: 04 Apr 2008
Status: Offline
Points: 12 		Post Options Post Options   Thanks (0) Thanks(0)   Quote XTRProf Quote  Post ReplyReply Direct Link To This Post Posted: 10 Apr 2008 at 2:24am

Originally posted by Graham Slee Graham Slee wrote:

Well XTRProf did say "shoot LOL"

Ha, ha, good reverberation there! Wink

Actually, I'm trying to get as much views on this as possible as there are some who said they like class D amp sound as they sounded a cross between tube and solid state and there are some who hated them like plague due to technicality like switching noise as measured on the scope. However, I'm neutral and the best sound wins whether technically or not. This is because we have to take into cosideration that there are things that measured horribly but sound fantastic and also things which our humble ears and brains just can't decipher like extreme high frequencies. Ya, something like A weightage and all that kind of jazz. Wink
Back to Top
dvv View Drop Down
Regular
Regular
Avatar

Joined: 12 Jan 2008
Location: Belgrade, Serbi
Status: Offline
Points: 95 		Post Options Post Options   Thanks (0) Thanks(0)   Quote dvv Quote  Post ReplyReply Direct Link To This Post Posted: 10 Apr 2008 at 6:30pm
@XTRprof
I think you misunderstood me.
 
I wondered why the highs sounded so unnatural, something very artificial in them. To my mind, unpleasant.
 
Now, I make it rule that before I connect anything to the oscilloscope, wide bandwidth generators, etc, I always, and that's ALWAYS, first ask around a circle of people I find to be well versed in the matter. Just in case, it never hurts to hear other people's views and experiences.
 
Being an old fart dangerously close to 55, over the years I have met in person and met via Internet quite a few people, with some of whom I have had the pleasure, and indeed honour, to stay in touch. You know one, Graham, and there are a few others, some of whom are not completely unknown. You might be surprised just how much stock I put in our own Graham's views - but that is the result of God knows, if even He, how many exchanged messages, some rather heated. Oh, I disagree with Graham quite a bit, but I'm not at all likely to do something radical until I've talked to Mr G.
 
So I talked to a select group, and believe it or not, got feedback much along the lines of my first message. After thinking over their experiences, I auditioned for myself, the usual gig, three rooms, three acoustics, three systems. And I got bad highs.
 
THEN I connected it to the scope. The point being I use the scope to try to see why am I hearing what I am hearing, not to tell me what I am hearing. Ears first, 'scope later.
Back to Top
dvv View Drop Down
Regular
Regular
Avatar

Joined: 12 Jan 2008
Location: Belgrade, Serbi
Status: Offline
Points: 95 		Post Options Post Options   Thanks (0) Thanks(0)   Quote dvv Quote  Post ReplyReply Direct Link To This Post Posted: 10 Apr 2008 at 6:44pm
Originally posted by Darren/Audio Elevati Darren/Audio Elevati wrote:

What about Class N, Graham.  Any better?   This from the Nuforce site...
 
"In order to suppress RF noise, speaker lead-out wires serving as high-frequency common-mode chokes are added to the circuit board. When a NuForce amp’s damping factor is taken at a speaker’s terminals, the number is 160, reflecting the wiring’s impedance and that of the output chokes."
 
Is there an English translation?  If not, a Yorkshire one?
 
Let me give it a try. What he's saying (and what he is not saying in brackets) is:
 
* * *
Our amp produces (a bagful of) RF noise. So we have to filter this (crap) out, and we use RF chokes. But the buggers are in series with the output and consequently influence our damping factor (which we know must be high enough to impress). So don't worry, you still have a damping factor of 160:1 (and we ain't stupid enough to tell you where, else you might be disappointed to learn it's at 1 kHz, but just 20:1 at 20 kHz). To minimize damage from the chokes, we'll include the wiring, which is like 0.001 Ohms and totally of no significance, but hey - does that sound good, or what?
* * *
 
That's about it. If I were you, I wouldn't worry, that's just a lot of analog noise sales blurb.
 
A small damping factor in the high range, 20 kHz, as long as it's 10:1 or more, is quite sufficient. You need a big one down in the bass cone operating range, to control the speaker's Q factor, but even so, anything over 20:1 worst case (say, 2 Ohms, so 20/40/80:1 for 2/4/8 Ohms) is generally academic.
 
It's far more important HOW you obtained it, but that's another story altogether.
Back to Top
dvv View Drop Down
Regular
Regular
Avatar

Joined: 12 Jan 2008
Location: Belgrade, Serbi
Status: Offline
Points: 95 		Post Options Post Options   Thanks (0) Thanks(0)   Quote dvv Quote  Post ReplyReply Direct Link To This Post Posted: 10 Apr 2008 at 7:02pm
Originally posted by Graham Slee Graham Slee wrote:

..."class T" varies the triangular wave up and down in frequency to make the HF distortion more palatable - a kind of phasing or flanging effect, and dvv, did you know a friend of ours actually thinks it sounds good!
 
Well, if his hearing is band limited to 10 kHz, why not? 10 kHz seems to be the trouble point from which upwards along the band troubles seem to appear with geometric progression.
 
What do you expect from kids who listen to heavily compressed MP3 all day along, all their lives, and think that's great sound? They start early, and in my experience, by 15, they have impaired hearing, true audio is totally wasted on them, their hearing has been damaged beyond repair.
 
You think I'm kidding when I say true audio lives on the fringes of the audio industry?
 
What have I ever done wrong to God for him to let me still hear 16 kHz at the age of 55? When most of my contemporaries don't hit even 12 kHz?
Back to Top
Analog Kid View Drop Down
Senior Member
Senior Member


Joined: 07 Mar 2008
Location: Germany
Status: Offline
Points: 209 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Analog Kid Quote  Post ReplyReply Direct Link To This Post Posted: 14 Apr 2008 at 4:54am
My amplifier is a Class H amplifier. Is Class H any good?
Back to Top
dvv View Drop Down
Regular
Regular
Avatar

Joined: 12 Jan 2008
Location: Belgrade, Serbi
Status: Offline
Points: 95 		Post Options Post Options   Thanks (0) Thanks(0)   Quote dvv Quote  Post ReplyReply Direct Link To This Post Posted: 14 Apr 2008 at 7:36am
@Analog Kid
Might be. It all depends on how it was originally done. By whom, which model?


Edited by dvv - 14 Apr 2008 at 7:37am
Back to Top
Graham Slee View Drop Down
Admin Group
Admin Group
Avatar
Retired

Joined: 11 Jan 2008
Location: South Yorkshire
Status: Offline
Points: 16314 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 14 Apr 2008 at 9:44am
Originally posted by Analog Kid Analog Kid wrote:

My amplifier is a Class H amplifier. Is Class H any good?


They are "inventing" new classes of amplifiers all the time, or that is what they'd have you believe.

Why not have class M, or class W, or...

There are simply the following classes of amplification: Class A, B, aB, C and D

All the others are made up!

Out of the above only classes A, B, aB, and D are any good for audio. Class C is used in single side band radio communication.
That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps
Back to Top
 Post Reply Post Reply Page  <123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.072 seconds.