MHz amplifier - Page 2 - 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 26th April 2008, 08:26 PM   #11
NeoY2k is offline NeoY2k  France
diyAudio Member
 
Join Date: Dec 2007
Nice and small stuff! And seems to work well!

Do you have any schematics?
Does it includes an AF error feedback?

The only paper I found is
http://class-d.net/tech/

If you could give me some information on this

Thanks,
Nicolas
  Reply With Quote
Old 26th April 2008, 08:46 PM   #12
Banned
 
Join Date: Jan 2005
Schemo is here.

My MCD is based on fumacīs block diagram.
  Reply With Quote
Old 27th April 2008, 05:03 AM   #13
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Hi, Tekko,

The (+) and (-) inputs are different points from Fumac's block diagram?
  Reply With Quote
Old 27th April 2008, 07:31 AM   #14
diyAudio Member
 
Bender.ru's Avatar
 
Join Date: Jan 2007
Location: Krasnogorsk-city
Hi Tekko!

what is advantage of 1..2 mHz carrier freq. amp compared with usual 300..400kHz carrier freq. amp?
or it's only "science" experiment ?
  Reply With Quote
Old 27th April 2008, 09:22 AM   #15
Banned
 
Join Date: Jan 2005
Lum, that have to do with that the LM311P output is inverting, if i use a TC4421, then the inputs would be the same as fumacīs block diagram.

Bender.ru, the higher switching frequency allows for more accurate reproduction of higher part of the audio band, class-d.net explains this.
  Reply With Quote
Old 27th April 2008, 11:05 AM   #16
diyAudio Member
 
Bender.ru's Avatar
 
Join Date: Jan 2007
Location: Krasnogorsk-city
what about switching precise?
  Reply With Quote
Old 27th April 2008, 11:30 AM   #17
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Hi, Bender,

I read Fumac's explenation here http://class-d.net/tech/ about the advantage of Mhz modulation. The loss (yellow triangle tip) seems can be applied if the system is forced clocked (triangle clocked).

Fumac, is this also applicable to self-oscillating classD? Isn't that in selfoscillating, it's self-adjusting towards errors?
  Reply With Quote
Old 27th April 2008, 12:20 PM   #18
Pabo is offline Pabo  Sweden
diyAudio Member
 
Join Date: Feb 2003
Location: Helsingborg, southern sweden
lumanauw

Quote:
is this also applicable to self-oscillating classD? Isn't that in selfoscillating, it's self-adjusting towards errors?
You are correct to some degree. Saying that a higher frequency improves the high frequency reproduction needs to be proven, not just taken for a theoretical to practical translation.

Self oscillating amplifiers gets more loop gain the more it attenuates the switching ripple but at some point the propagation delay and switching nonlinearities will take over and cause more distortion. My experience is that going above 600kHz is difficult without generating very high levels of radiated emissions. Of course if one is only building for DIY it would be OK as long as the neighbours pace maker does not stop.

Saying that EMI decreases when the switching frequency is pushed above 1MHz is pure fantasy and based only on the assumption that if the residual decreases in amplitude the EMI decreases. If you switch twice as many times the radiated emissions double and if you want to use this higher frequency for improving the sound the DV/DT need to be shortened easily doubling the radiated noise again.
__________________
If something that measures good doesnīt sound good, measure again!
  Reply With Quote
Old 27th April 2008, 02:54 PM   #19
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Fumac's claims are not based on scientific criteria.
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 27th April 2008, 04:23 PM   #20
latala is offline latala  United Kingdom
diyAudio Member
 
Join Date: Feb 2006
Location: staffordshire
I like the look of this! and it may be a usefull introduction to class D can you provide component values ?
I have tried without success to make a simple class d but all I get is smoke
Regards Trev
  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
Wanted: DIY amplifier builder with experience. I need a 0.7 ohm stable amplifier Audiophilenoob Swap Meet 34 16th May 2005 11:58 PM
Questions about how to decrease the PASS A-40 amplifier into a class AB amplifier. novtango Pass Labs 2 21st October 2002 01:50 AM


New To Site? Need Help?

All times are GMT. The time now is 10:26 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2