MY DESIGN L20D IRS2092+IRFI4020H 200W8R - Page 78 - 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 20th October 2013, 12:47 PM   #771
diyAudio Member
 
Join Date: Feb 2013
Quote:
From redjr:
I certainly don't dislike the sound of the LJM ISR2092 based-amps. Goodness knows. I have 5 of his design so I'm happy. I'm sure the sound can be improved even more with better speakers and listening arrangement. None of which I have at the moment. Click the image to open in full size. I recently replaced a Sure module with one of Cristi's design and it does sound very, very good. Better than the LJM? I'm not so sure. That's a close call. Only because I've never done any real serious A/B listening/testing of the two.
I completly agree:
I am not an ingeener, but I think the most important is the result, so maybe we need some KPI or indicators to compare user satisfaction for class D chips and architectures.
Saying that, I don't really understand why there are so many discussions around post filters, etc... For me, this is just different architectures to compare, with a user approach.
For L15D, there are measurements done in another thread that prove the quality of the sound.
Maybe it is not as good as a $1000 amplifier, but the result is more than decent compare to some class B or other class D.
So, what else to discuss?

My system:
I have a LJM L15D with a Connexelectronic SMPS.
a chinese Matisse PREAMP,
a HIFIMEDIY SABRE DAC with a RASPBERRY as source.

I have to say it is not perfect with high frequencies (it is a little bit crispy), and low frequencies are a little bit flat, but the averall sound is really better than my expectations, and I have to say the sound quality is far better than my Denon Home cinema amplifier.
  Reply With Quote
Old 20th October 2013, 06:35 PM   #772
diyAudio Member
 
wushuliu's Avatar
 
Join Date: May 2008
Location: Los Angeles
Quote:
Originally Posted by camelator View Post
I completly agree:
I am not an ingeener, but I think the most important is the result, so maybe we need some KPI or indicators to compare user satisfaction for class D chips and architectures.
Saying that, I don't really understand why there are so many discussions around post filters, etc... For me, this is just different architectures to compare, with a user approach.
For L15D, there are measurements done in another thread that prove the quality of the sound.
Maybe it is not as good as a $1000 amplifier, but the result is more than decent compare to some class B or other class D.
So, what else to discuss?

My system:
I have a LJM L15D with a Connexelectronic SMPS.
a chinese Matisse PREAMP,
a HIFIMEDIY SABRE DAC with a RASPBERRY as source.

I have to say it is not perfect with high frequencies (it is a little bit crispy), and low frequencies are a little bit flat, but the averall sound is really better than my expectations, and I have to say the sound quality is far better than my Denon Home cinema amplifier.
The greater concern is whether the LJM boards on ebay now are performing to spec. From what I have read through this thread it sounds like initially they were fine but now at the very least some are not. When you buy these from ebay it's not like you are buying them from LJM, there is no seal of approval just because the board says 'LJM' so his measurements are irrelevant at this point. What you're hearing could be a poor implementation. If you like what you hear great, but I wouldn't judge the LJM IRS2092 vs other amps unless I knew for sure it was performing to spec.

Last edited by wushuliu; 20th October 2013 at 06:41 PM.
  Reply With Quote
Old 1st November 2013, 06:05 PM   #773
diyAudio Member
 
Join Date: Dec 2009
Hi, I'm projecting amplifier for home theater, I want to use irs2092s for all channels
there was a couple of questions, I will have 6 channels in a single package powered by sg3525
- Do I need to synchronize the 6 channels?
- Do 6 channels on a single board or different?

thank you
  Reply With Quote
Old 14th November 2013, 02:45 PM   #774
Huey is offline Huey  United States
diyAudio Member
 
Join Date: Jun 2003
Location: Seattle, WA
I'm planning on getting a couple of these modules to put togther an amplifier. I have a 300VA 115v to 38-0-38 toroid transformer to make a power supply with. This will give me an output voltage of around +/-55VDC. Which version is the proper one to go with this? The L15D or the L25D?

Also, this will be my first power supply. I see I need a bridge rectifier and output filter caps. Are any other components required or is it really that simple?
  Reply With Quote
Old 15th November 2013, 11:48 PM   #775
Huey is offline Huey  United States
diyAudio Member
 
Join Date: Jun 2003
Location: Seattle, WA
After rereading some of this thread with my question in mind I see that the L15D can handle this voltage (a few posts said it was for a lower supply voltage and through me off.).

As for the power supply I'm looking at picking up a PCB, capacitors, and rectifier kit to use with my transformer. The two I'm looking at are:

68 220uF board: 68pcs 75V 220uf Original RUBYCON YXF Capacitor Power supply board kit /PSU kit #0506 13-in Other Electronic Components from Electronic Components & Supplies on Aliexpress.com

or this 8x 2200uF board: LJM Audio Power supply kit ( 8 X 63V2200UF capacitors) suitable for L20,L12 2,L6,MX50,Quad 405 amp board-in Other Electronic Components from Electronic Components & Supplies on Aliexpress.com

Any thoughts on which would be best? Or other suggestions?

Thanks.
  Reply With Quote
Old 16th November 2013, 05:09 PM   #776
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Transformer output of 38 VAC RMS will give a peak of 53.7 Volts but then you have to subtract two diode drops.

Look at the rectifier datasheet and find the voltage drop (Vf, "Forward Voltage") for when the diodes are conducting about 5X your maximum RMS speaker current. (i.e. Assume the speaker current is continuously going. Then assume that the rectifier diodes only conduct for a short time during each cycle, maybe 1/5th of the time. The diodes have to send all of the current, but in 1/5th [or whatever it is] of the time, since they only conduct during the charging pulses, which might be 1/3rd to 1/5th of the time.)

If the diodes could drop 1 Volt each (2 Volts total), for example, then your DC could be as low as 51.7 Volts.

Maybe some bridges use Schottky diodes, which would cut their drop by about half, possibly giving you another Volt or so.
__________________
The electrolytic capacitors ARE the signal path: http://www.fullnet.com/~tomg/zoom3a_33kuF.jpg
  Reply With Quote
Old 16th November 2013, 05:31 PM   #777
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Quote:
Originally Posted by Huey View Post
After rereading some of this thread with my question in mind I see that the L15D can handle this voltage (a few posts said it was for a lower supply voltage and through me off.).

As for the power supply I'm looking at picking up a PCB, capacitors, and rectifier kit to use with my transformer. The two I'm looking at are:

68 220uF board: 68pcs 75V 220uf Original RUBYCON YXF Capacitor Power supply board kit /PSU kit #0506 13-in Other Electronic Components from Electronic Components & Supplies on Aliexpress.com

or this 8x 2200uF board: LJM Audio Power supply kit ( 8 X 63V2200UF capacitors) suitable for L20,L12 2,L6,MX50,Quad 405 amp board-in Other Electronic Components from Electronic Components & Supplies on Aliexpress.com

Any thoughts on which would be best? Or other suggestions?

Thanks.
I really like the idea of lots of smaller paralleled caps.

But you could build your own cap array, very easily, instead, with no etching required:

If you acquire a bare two-sided PCB, you could drill one hole for each cap, and remove a small ring of copper from around each hole (Dremel tool?), on the top side of the PCB. Then insert one cap lead through a hole and solder on bottom, with other lead bent parallel to top copper and soldered to it.

One side of the PCB would be a supply rail and the other side would be ground.

You could divide one side of a PCB by removing a thin line of copper all the way across, and make two supply rails on one PCB.

The large un-broken copper planes would give VERY low inductance (and ESR). For best impedance characteristics, use very thin PCB; maybe 0.5 mm thickness.

Feed from rectifiers to one edge of the PCB and supply your circuit from the opposite edge.

Don't make the array too long and thin; nearer to square is probably better. And use very short and fat wires to connect board output, so you don't destroy the beautiful low inductance.

There are posts you could find, on diyaudio, where Terry Given proposed this and then built one that he measured with his network analyzer.
__________________
The electrolytic capacitors ARE the signal path: http://www.fullnet.com/~tomg/zoom3a_33kuF.jpg
  Reply With Quote
Old 17th November 2013, 01:04 PM   #778
diyAudio Member
 
Join Date: Apr 2010
Location: Brisbane
Quote:
Originally Posted by chienmort View Post
Thank you Rens. Move your tagline BTW.
? Please explain

Cheers ,

Rens
__________________
If you measure, you know; if you guess, you don't
  Reply With Quote
Old 17th November 2013, 03:13 PM   #779
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
Maybe it was meant to say LOVE instead of MOVE.
__________________
The electrolytic capacitors ARE the signal path: http://www.fullnet.com/~tomg/zoom3a_33kuF.jpg
  Reply With Quote
Old 17th November 2013, 09:00 PM   #780
diyAudio Member
 
Join Date: Apr 2010
Location: Brisbane
Quote:
Originally Posted by gootee View Post
Maybe it was meant to say LOVE instead of MOVE.
Thanks ! Finally understand what my wife said
__________________
If you measure, you know; if you guess, you don't
  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 09:51 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