CLASS AB Amplifier Vs CLASS D Amplifier - 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 27th August 2011, 07:52 PM   #1
diyAudio Member
 
Join Date: Aug 2011
Post CLASS AB Amplifier Vs CLASS D Amplifier

Hi all,

Iam planning to build a two Way plate amplifer. For the LF Section iam planning to use a Class D Amplifier Module the power is 400W @ 4 Ohms.

For the HF sction which amplifier type would be best. The Wattage of the HF is 100W.

Some people say that CLASS AB Module is better for HF section and some people say CLASS D Module will be good.

So please advice me on this whether to use Class AB or Class D module for the HF Section.

Help me on this:confused::confused::confused:.

Thankx
  Reply With Quote
Old 27th August 2011, 09:14 PM   #2
diyAudio Member
 
Saturnus's Avatar
 
Join Date: Jun 2005
Location: Copenhagen, Denmark
Modern class D amps rival and surpass most class AB amps in sound quality at a much lower price and vastly lower power consumption.

Class AB amps are in my opinion a relic of the past, gone the same way as tube amps, vinyl records, and AM radio. Sure, some people will still swear to them but they're more an oddity having no value in themselves beyond nostalgism.
  Reply With Quote
Old 27th August 2011, 10:02 PM   #3
diyAudio Member
 
Join Date: Aug 2004
Location: Uppsala,Sweden
Quote:
Originally Posted by Saturnus View Post
Modern class D amps rival and surpass most class AB amps in sound quality at a much lower price and vastly lower power consumption.

Class AB amps are in my opinion a relic of the past, gone the same way as tube amps, vinyl records, and AM radio. Sure, some people will still swear to them but they're more an oddity having no value in themselves beyond nostalgism.
I disagree, most people get headaches from listening to music through a class D amp!

Seriously, I still disagree to the categoric statement above and BTW its noting wrong to use a tube amp or vinyl records if you like it this way.
__________________
Without wonderment,no life.
  Reply With Quote
Old 27th August 2011, 10:19 PM   #4
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
I have designed class AB and class D amps and to be honest cant tell the difference just by listening.

The class d amp has the benefits of using less power and requiring a smaller heatsink and using fewer components.
  Reply With Quote
Old 28th August 2011, 01:34 AM   #5
diyAudio Member
 
Saturnus's Avatar
 
Join Date: Jun 2005
Location: Copenhagen, Denmark
Quote:
Originally Posted by The golden mean View Post
Seriously, I still disagree to the categoric statement above and BTW its noting wrong to use a tube amp or vinyl records if you like it this way.
A categoric statement usually don't start with: "In my opinion..."
  Reply With Quote
Old 28th August 2011, 01:58 AM   #6
gychang is offline gychang  United States
diyAudio Member
 
Join Date: Feb 2005
Location: Davis, California
Quote:
Originally Posted by The golden mean View Post
I disagree, most people get headaches from listening to music through a class D amp!

I listen to class D amp, many different kinds mainly from Helder's. I get no headaches and sounds excellent IMHO. I am not into tubes, exotic stuff, just mainly vocal/jazz/small group classical...
__________________
--
Good sound from Davis, CA
  Reply With Quote
Old 28th August 2011, 02:02 AM   #7
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Quote:
Originally Posted by gychang View Post
I am not into tubes, exotic stuff, just mainly vocal/jazz/small group classical...
I have a class d amplifier with a tube front end, best of both worlds.
  Reply With Quote
Old 28th August 2011, 02:44 AM   #8
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
 
Join Date: Nov 2005
I would suggest to build two stereo amps, one each channel

or you could 3 smaller amps of equal design
bridge two of them for LF
and the other for HF
this way you get a high power and a low power amp running on the same voltage

though, a bridged amp into 4ohm may be a tough one
  Reply With Quote
Old 28th August 2011, 03:10 AM   #9
opc is offline opc  Canada
diyAudio Member
 
opc's Avatar
 
Join Date: Oct 2004
Location: Ottawa, Ontario, Canada
Hi nkdecibels,

From a performance and sound quality standpoint, there's no question that a class AB, or better yet a class A amplifier would be your best choice. The only reason to use class D is high power density and better efficiency.

Class D pros:
1. Higher power density (both in size and weight)
2. Higher efficiency
3. Potentially lower cost

Class D cons:
1. Limited power Bandwidth
2. Lower SNR
3. Higher THD
4. Response that varies with load
5. Higher circuit complexity
6. EMI/EMC related issues

So in short, if you're building a powered monitor for portable PA use, then you'd be a fool to use anything but class D. For any application where sound quality is a primary concern, class A or class AB are the way to go.

I know there will be some who disagree, but I would like for them to show just one sound quality related area where a class D is better. I have yet to find one, and used to design class D amps for a living!

As a side note, are you sure you need 100W for your tweeter? That's a lot of power to be feeding into a tiny driver. Dropping that requirement would allow you to use something like an F5 which would really be the cat's meow.

Cheers,
Owen
  Reply With Quote
Old 28th August 2011, 03:17 AM   #10
diyAudio Member
 
Join Date: Apr 2006
Location: Reykjavk
opc, may I humbly suggest that there have been developments in Class D that elimiate any of the disadvantages you mention:

Quote:
Originally Posted by opc View Post
Class D cons:
1. Limited power Bandwidth
2. Lower SNR
3. Higher THD
4. Response that varies with load
5. Higher circuit complexity
6. EMI/EMC related issues
1 - Not that I know of. Perhaps I don't understand. Can you elaborate?
2 and 3 - Here are some measurements of a good, clean Tripath TA3020 amplifier, the 41Hz Amp15 which gives 0.008% THD+N at up to 74Wrms, and a noise floor below -120dBV. (And the IMD performance of good Class D is excellent too!) It is possible to reduce the distortion figure further, and increase power, with modifications / choice of chipset. I suspect that the Hypex NCore will then be significantly quieter and cleaner.
4 - Not likely to matter significantly in practice. Furthermore, Hypex UcD and NCore, and other designs, do away with this limitation entirely.
5 - Not likely to matter in practice. Secondly, Class D amps are much more efficient, and a populated board for a high-power Class D amp with very high sound quality is possibly going to be much cleaner and smaller than a similar Class A; Also more reliable due to less heat, and more quiet due to less stray inductance etc. in the signal path.
6 - If the design is done properly, then Class D amps don't need much shielding. Add minimal shielding and the environment is as good as EMI-free.

Last edited by kristleifur; 28th August 2011 at 03:21 AM.
  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
Class AB Amplifier - New to the analog world ea6b607 Solid State 40 28th March 2011 08:28 PM
Pi filter for Class AB amplifier, feedback please pjpoes Solid State 4 21st March 2007 10:27 AM
A good Brazilian Amplifier, class A switching to AB in hi power destroyer X Solid State 65 24th March 2005 09:12 PM
Class AB Amplifier USFishin Solid State 1 28th March 2004 04:25 PM
Questions about how to decrease the PASS A-40 amplifier into a class AB amplifier. novtango Pass Labs 2 21st October 2002 02:50 AM


New To Site? Need Help?

All times are GMT. The time now is 03:51 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2