0.0004% THD Class D Module - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th November 2005, 12:43 PM   #1
diyAudio Member
 
Join Date: Oct 2003
Location: The Lab
Default 0.0004% THD Class D Module

Using the (rather radical..) new measurement methods as proposed by Per Anders, i hereby post the first measurements of THD on the 700XE.

I guess the serious message in this result is that pre filter NFB can give as good THD measurement as post filter NFB.

Take a look below
Attached Images
File Type: jpg 700xethd.jpg (27.0 KB, 1105 views)
__________________
www.newclassd.com
  Reply With Quote
Old 7th November 2005, 12:52 PM   #2
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Did I? Forgot it already

How does it sound then, the obvious question? Pretty certain that you at least are pleased, yes?

Do you have a more revealing picture than the one you have on your website?
__________________
/Per-Anders (my first name) or P-A as my friends call me
  Reply With Quote
Old 7th November 2005, 01:26 PM   #3
KLe is offline KLe  Australia
Banned
 
Join Date: Jul 2005
Location: Brisbane
Hi Lars

Excellent THD results, and what, there for a pre filter NFB design!!!

As peranders asked, "How does it sound then ..."

Lars, the graph only goes to 10K, what's the THD from 10K to 20K?
  Reply With Quote
Old 7th November 2005, 04:01 PM   #4
diyAudio Member
 
Join Date: Oct 2003
Location: The Lab
Hi KL

Well the THD between 10 and 20 kHz is usually eaten up by the 24 kHz 'brick wall' filter.

For example if you take a 3rd harmonic THD of 10 kHz, the harmonic will be at 30 kHz, and simply vanishes in the AES filter.
__________________
www.newclassd.com
  Reply With Quote
Old 7th November 2005, 04:33 PM   #5
BWRX is offline BWRX  United States
diyAudio Moderator Emeritus
 
Join Date: Jan 2005
Location: Pennsylvania
Just curious - what kind of load was used and what output power was the test done at?
  Reply With Quote
Old 7th November 2005, 05:32 PM   #6
diyAudio Member
 
Join Date: Oct 2003
Location: The Lab
This is 2 W rms in 8 Ohms
__________________
www.newclassd.com
  Reply With Quote
Old 7th November 2005, 06:15 PM   #7
IVX is offline IVX  Russian Federation
diyAudio Member
 
IVX's Avatar
 
Join Date: Jul 2003
Location: Everywhere (Buddhist's context)
Lars, can you show us THD/Power plots for 200Hz, 1KHz, 6KHz? Do you know about how much the loop gain in your amp? What is the (rather radical..) new measurement methods, really?
__________________
Best regards,
E1.
  Reply With Quote
Old 7th November 2005, 07:25 PM   #8
diyAudio Member
 
Join Date: Oct 2003
Location: The Lab
IVX: Kind of a joke between me and Per Anders. From another thread.

And please note, the posted THD data are real, but NOT official data release.. I just posted the best looking results i could get (under the most beneficial op conditions .. but not totally useless anyway).
Of course a more parametric result will be released later on.
__________________
www.newclassd.com
  Reply With Quote
Old 8th November 2005, 02:23 AM   #9
TerryG is offline TerryG  United States
diyAudio Member
 
Join Date: Nov 2005
Location: Northern California
This is the problem I have found with measurements, if not measured with a true inductive load then your not getting real world results. If you can get below 0.01 with a real speaker including crossover, then you have something.

Why does the brick wall have to be at 24k Hz, can't that point be higher and still not have a great deal of noise? And if the noise is above 20K why do we worry about it so much, or why is it even audible? These are honest questions here. The best switch mode amp I have ever heard was noisier than most, but during music levels you didn't even notice the noise.
  Reply With Quote
Old 8th November 2005, 08:25 AM   #10
diyAudio Member
 
Join Date: Oct 2003
Location: The Lab
Quote:
measured with a true inductive load
.. or even a loudspeaker ..
__________________
www.newclassd.com
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
SMPS for class D module NewTesla Class D 40 16th May 2010 08:38 PM
Dlogixs class X module.. MatthewS Car Audio 1 6th April 2008 11:47 PM
ILP HCA40 - Class A module info JDeV Chip Amps 0 31st August 2005 01:48 PM
Cad Audio - another Class-D module raintalk Class D 0 9th November 2004 11:09 PM


New To Site? Need Help?

All times are GMT. The time now is 12:03 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright İ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2