new LM4780 layout, any comments? - Page 4 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 2nd May 2009, 05:47 AM   #31
diyAudio Member
 
katana2112's Avatar
 
Join Date: Jan 2008
YGM
__________________
Aggressively Passive
  Reply With Quote
Old 2nd May 2009, 06:56 AM   #32
sasmit is offline sasmit  India
diyAudio Member
 
Join Date: May 2006
Send a message via Yahoo to sasmit
I have made a pcb using national's art work as a guide, it may not be upto scratch..it works without any hum hiss and sounds good too.. comments welcome..

Click the image to open in full size.
  Reply With Quote
Old 2nd May 2009, 07:02 AM   #33
sasmit is offline sasmit  India
diyAudio Member
 
Join Date: May 2006
Send a message via Yahoo to sasmit
with components...not cleaned
have changed a few components after this pic..decoupling cap near IC to monolithic ceramics in place of wima films.
Click the image to open in full size.
  Reply With Quote
Old 2nd May 2009, 07:03 AM   #34
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
If you attach a pic, do not preview the post, otherwise the attachment will disappear.

I also suggest that you create a new thread for better visibility.
  Reply With Quote
Old 2nd May 2009, 07:09 AM   #35
sasmit is offline sasmit  India
diyAudio Member
 
Join Date: May 2006
Send a message via Yahoo to sasmit
didn't want to create an exact same thread..so just posted my pics here...my apologies for disturbing this thread..
  Reply With Quote
Old 2nd May 2009, 07:14 AM   #36
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Quote:
Originally posted by gfiandy
Hi Brian,

You have used split bridges for the power supply for the two different rails and then shared the current paths back to the trasformer buy usign one big plane between the capacitors.

Since you have split the rectification with two bridges, the rectifier currents will flow in a loop through the capacitor C10 and 12 for the +ve rail and C9 and C11 for the -ve rail. This means that to get the minimum rectifier noise on your star point you want to split the return paths for these two rectifiers and join them back at the connection between the two rectifiers. Then a third path should join at the rectifiers to feed the rest of the amplifer star. This way none of the rectifier currents flow in copper shared with the star point, this should reduce the ripple on the ground slightly.

Since you have already had the boards made you could try this out by cutting two slots into the ground plan to isolate a path up to the "star point" OG gnd.

This is only a minor point as you already have a good design but since you are cleary wanting to get the best out of it it may give you a slight improvement.

Regards,
Andrew
Like so?
Attached Images
File Type: jpg 4780-cut.jpg (85.6 KB, 698 views)
  Reply With Quote
Old 8th May 2009, 03:28 PM   #37
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
I could give that a try. I finally got around to building a new LM4780 prototype amp last night:
Click the image to open in full size.
full size: http://www.briangt.com/gallery/lm4780r2/lm4780?full=1
ignore my lack of chassis for now

I configured the amp in stereo configuration for this one. Will try building a pair of parallel amps next.

--
Brian
  Reply With Quote
Old 8th May 2009, 03:56 PM   #38
nrg2009 is offline nrg2009  United States
diyAudio Member
 
Join Date: Apr 2009
Location: Detroit, born and raised in the netherlands.
Looks great Brian! How does it sound? How does it compare to your other amps?
  Reply With Quote
Old 8th May 2009, 10:25 PM   #39
diyAudio Member
 
Join Date: May 2009
Send a message via AIM to bmwman91
Very cool! I have been wondering...what is the difference between the LM4780 & LM3886? They seem to be the most popular chips in here, and there's the obvious difference that the the LM4780 has 2 channels. According to their datasheets, it looks like the LM4780 has the same or less THD+N at higher power outputs. Is this correct?

I plan to build a 4ch chip amp (bi-amping some 2-way's I built a while ago), as soon as the current project is done. I opted to make some nice red oak tables for the speakers to get them off my desk...then I will move on to the DIY amp part of it.

Thanks!
  Reply With Quote
Old 8th May 2009, 11:02 PM   #40
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Got a question about the casework. I notice that the piece you've bolted to the chip will likely be a chassis panel in the future. How best to drill the holes so that everything fits? I mean, to get the spacing between the chip hole and the standoff holes correct.
  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
Crossover Layout Comments luvdunhill Multi-Way 13 4th February 2009 02:50 PM
Need comments on this P3A PCB layout goering Solid State 7 27th August 2004 06:04 AM
My new Aleph layout. Comments? louischia Pass Labs 12 18th May 2003 08:02 PM


New To Site? Need Help?

All times are GMT. The time now is 01:21 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