MY DESIGN L20D IRS2092+IRFI4020H 200W8R - Page 46

vakkuj · 12th May 2012, 06:06 AM

I have not seen any wiring information with LJM's new board power supply + speaker protection board.
Will be glad if any one could point me to the specific post.
Thank you

clm811 · 13th May 2012, 01:44 AM

Received my L25D Boards, and everything looks good, except:

There was no thermal compound on the H669A BJC or IRFB4020's, so I applied some.

While operating at approximately 10wattsrms, the H669A BJC and three green resistors got very hot(could not keep finger on it for any time).

For this thing to be capable of 300W I believe a larger heat sink will be needed.

Opinions, or similar experience to share?

-Chas

nigelwright7557 · 13th May 2012, 01:51 AM

Its surprising how small a heatsink you can get away with for class d.
I test my 750 watt amps on full power for a few seconds with no heatsink and the transistors dont get hot.

Components can run very hot yet still be well inside their SOA.
Power resistors do tend to run hot anyway.

ionutzxpo · 13th May 2012, 07:47 AM

hi,on my L25D the two rezistors from 5V6 diodes are at 40 degrees and the on at the NPN tranzistor has allmost 60 degrees yet the amp works non stop over 1 month

solviken · 13th May 2012, 12:53 PM

So i just finished my l25D amp. with a 650watt 2x50vac and 60 000uF psu thats feeding the boards with 70vdc.

When i crank up the sound to very high volums one of the bords just shuts of and the otherone continiue. Then i have to turn the volum a little down and it comes back!

Any ideas why?

ionutzxpo · 13th May 2012, 03:28 PM

the amp reaches hard clipping and protection mode is activated!

solviken · 04:03 PM

Quote:

Originally Posted by ionutzxpo

the amp reaches hard clipping and protection mode is activated!

So then it has reached its max output? Do you think it will perform better with active cooling?

But how is it possible to Get clipping from a 250w amplifier.. When its impossible to get the Rotel RB1070 with its puny 125w to go into protection mode!

ionutzxpo · 13th May 2012, 04:31 PM

read the application note for irs2092

solviken · 13th May 2012, 04:38 PM

Will do

solviken · 13th May 2012, 11:06 PM

I thought that i should share my Almost finished L25D project

Still havent added the Speaker protection board, cause i dont have anything to power it with ATM.

Here are som pictures!

IMG_4605.JPG

IMG_4606.JPG

IMG_4614.JPG

IMG_4618.JPG

IMG_4626.JPG

13th May 2012, 01:51 AM	#453
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	Its surprising how small a heatsink you can get away with for class d. I test my 750 watt amps on full power for a few seconds with no heatsink and the transistors dont get hot. Components can run very hot yet still be well inside their SOA. Power resistors do tend to run hot anyway. __________________ http://www.murtonpikesystems.co.uk PCBCAD50 pcb design software.

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12th May 2012, 06:06 AM	#451
vakkuj diyAudio Member Join Date: May 2010	I have not seen any wiring information with LJM's new board power supply + speaker protection board. Will be glad if any one could point me to the specific post. Thank you

13th May 2012, 01:44 AM	#452
clm811 diyAudio Member Join Date: May 2002 Location: Northern California	Received my L25D Boards, and everything looks good, except: There was no thermal compound on the H669A BJC or IRFB4020's, so I applied some. While operating at approximately 10wattsrms, the H669A BJC and three green resistors got very hot(could not keep finger on it for any time). For this thing to be capable of 300W I believe a larger heat sink will be needed. Opinions, or similar experience to share? -Chas

13th May 2012, 07:47 AM	#454
ionutzxpo diyAudio Member Join Date: Sep 2009 Location: Romania,Calarasi	hi,on my L25D the two rezistors from 5V6 diodes are at 40 degrees and the on at the NPN tranzistor has allmost 60 degrees yet the amp works non stop over 1 month

13th May 2012, 12:53 PM	#455
solviken diyAudio Member Join Date: Feb 2012	So i just finished my l25D amp. with a 650watt 2x50vac and 60 000uF psu thats feeding the boards with 70vdc. When i crank up the sound to very high volums one of the bords just shuts of and the otherone continiue. Then i have to turn the volum a little down and it comes back! Any ideas why?

13th May 2012, 03:28 PM	#456
ionutzxpo diyAudio Member Join Date: Sep 2009 Location: Romania,Calarasi	the amp reaches hard clipping and protection mode is activated!

13th May 2012, 04:31 PM	#458
ionutzxpo diyAudio Member Join Date: Sep 2009 Location: Romania,Calarasi	read the application note for irs2092

13th May 2012, 04:38 PM	#459
solviken diyAudio Member Join Date: Feb 2012	Will do

13th May 2012, 11:06 PM	#460
solviken diyAudio Member Join Date: Feb 2012	I thought that i should share my Almost finished L25D project Still havent added the Speaker protection board, cause i dont have anything to power it with ATM. Here are som pictures! IMG_4605.JPG IMG_4606.JPG IMG_4614.JPG IMG_4618.JPG IMG_4626.JPG