MY DESIGN L20D IRS2092+IRFI4020H 200W8R - Page 23 - 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 30th October 2011, 12:25 AM   #221
diyAudio Member
 
Join Date: Jul 2004
Location: Mountain View, CA
Quote:
Originally Posted by trevmar View Post
...the main capacitors measured 0.12 ohms ESR and so were headed to the junkheap as soon as they crossed my doorstep, as I draw the line at about 0.05 ohms right now
Does the ESR affect sound quality and/or efficiency/heat (do these pass output current?)

Also curious about your opinion on use of electrolytics as blocking caps on the input; did you change those?

Quote:
Originally Posted by ljm_ljm View Post
I'm going to see this circuit, that you should be calculated is correct.

Reverse phase input virtual ground, so input impedance should be 1 / (1/100 K + 1/3.33 K)

Thank you for your correct.
Is this correct? What about R8, 120k?

This is important to me so I can properly calculate a passive shelf filter to correct an issue with my L/R speakers.
__________________
-----------------------------------------
Noah
  Reply With Quote
Old 30th October 2011, 04:55 AM   #222
diyAudio Member
 
Join Date: Jul 2004
Location: Mountain View, CA
I'm confused on the correct values for the main caps, shown on p.21 fig.25 here

http://www.inductor.com/irf/iraudamp7s.pdf

If my rudimentary understanding of circuits is right, they're CP7 and CP8.

I wonder why they're "CP" and not just "C", and why they're printed in red and have asterisks in front of the 470uF.
__________________
-----------------------------------------
Noah
  Reply With Quote
Old 30th October 2011, 05:07 AM   #223
MrSlim is offline MrSlim  Canada
diyAudio Member
 
Join Date: Jun 2009
Location: Ottawa, Ontario
Blog Entries: 2
From the BOM , it looks like the CP's are electrolytics , and the C's are non electrolytics..
  Reply With Quote
Old 30th October 2011, 05:15 AM   #224
diyAudio Member
 
Join Date: Jul 2004
Location: Mountain View, CA
ah right, P for polarized
__________________
-----------------------------------------
Noah
  Reply With Quote
Old 30th October 2011, 05:35 AM   #225
ljm_ljm is offline ljm_ljm  China
diyAudio Member
 
Join Date: Sep 2006
Quote:
Originally Posted by pheonix358 View Post
Hi all, nice thread, nice amps!

I am a little confused. I assume I can only purchase these on Ebay.

eBay My World - along1986090
eBay My World - zoe_tsang

Both of these sellers have them. Is one better than the other? Are both authorized to sell them?

Thanks in advance

Terry

Yes, there are two authorized only.
  Reply With Quote
Old 30th October 2011, 05:37 AM   #226
ljm_ljm is offline ljm_ljm  China
diyAudio Member
 
Join Date: Sep 2006
Quote:
Originally Posted by noah katz View Post
Does the ESR affect sound quality and/or efficiency/heat (do these pass output current?)

Also curious about your opinion on use of electrolytics as blocking caps on the input; did you change those?



Is this correct? What about R8, 120k?

This is important to me so I can properly calculate a passive shelf filter to correct an issue with my L/R speakers.

They are inverse the amplifier circuits, there are many material are described in content.

Before I ignore this, in the capacity of the capacitance on use size, 22 UF is more reasonable.

So we don't have to change it.
  Reply With Quote
Old 30th October 2011, 07:28 AM   #227
diyAudio Member
 
Join Date: Jul 2004
Location: Mountain View, CA
Quote:
Originally Posted by ljm_ljm View Post
Before I ignore this, in the capacity of the capacitance on use size, 22 UF is more reasonable.
My question is not about the 22uF value, it is whether it is advisable to use a nonpolarized electrolytic capacitor for an AC audio signal.
__________________
-----------------------------------------
Noah
  Reply With Quote
Old 30th October 2011, 06:26 PM   #228
diyAudio Member
 
Join Date: Jul 2004
Location: Mountain View, CA
I thought that crossover distortion wasn't an issue for class D because they don't construct the output waveform from two halves like AB designs, but then I came across this:

Quote:
Originally Posted by phase_accurate View Post
Class-d in general do have a very different crossover behaviour than linear amps. There is always an alternating idling current flowing through the output inductor at no or low output power. This current is greatly supporting the switching process. At the very point when the output current in the load approaches the value of the idling current a class-d amp's crossover takes place. This is usually at a few watts. There are amps where this is intentionally pushed to higher output power levels by the use of smaller inductors (and therefore increased idling current).
Is this true for the IRS2092-based modules?

If so, what is the freq of this alternating idling current?

The only evidence is a small bump at 20W in some of the THD+N vs. power graphs, but curiously only in one channel.
__________________
-----------------------------------------
Noah
  Reply With Quote
Old 31st October 2011, 01:17 AM   #229
ljm_ljm is offline ljm_ljm  China
diyAudio Member
 
Join Date: Sep 2006
Quote:
Originally Posted by noah katz View Post
My question is not about the 22uF value, it is whether it is advisable to use a nonpolarized electrolytic capacitor for an AC audio signal.

ordinary power amplifier is the same. Of course can use any capacitors.
  Reply With Quote
Old 31st October 2011, 05:14 AM   #230
MrSlim is offline MrSlim  Canada
diyAudio Member
 
Join Date: Jun 2009
Location: Ottawa, Ontario
Blog Entries: 2
Quote:
Originally Posted by noah katz View Post
I thought that crossover distortion wasn't an issue for class D because they don't construct the output waveform from two halves like AB designs, but then I came across this:



Is this true for the IRS2092-based modules?

If so, what is the freq of this alternating idling current?

The only evidence is a small bump at 20W in some of the THD+N vs. power graphs, but curiously only in one channel.
It's probably the self generated 400Khz frequency that is used as part of the Class D design..
  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
IRS2092 Amp Design: Please help! Devendra Class D 11 17th March 2011 09:10 AM
IRS2092 Amp Design Review brent113 Class D 22 17th June 2010 05:30 PM
IRS2092 help! yudi02 Class D 2 11th October 2009 03:30 AM
Design help needed for IRS2092 cmhadley Class D 1 2nd January 2009 11:06 PM


New To Site? Need Help?

All times are GMT. The time now is 11:22 AM.


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