LM3876 for small sub amp? - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 2nd July 2006, 04:24 AM   #11
ir is offline ir  New Zealand
diyAudio Member
Join Date: Aug 2003
Location: WGTN, NZ
Send a message via ICQ to ir
i use a 3876 power amp driving a 15in sub. works beautifully and runs to VERY high volumes without trouble

fan forced cooling will probably be overkill unless you're using a very small heatsink
  Reply With Quote
Old 5th July 2006, 05:50 PM   #12
diyAudio Member
Join Date: Apr 2005
Location: In the Wild, Wild West
Just be sure you connect pin 5 correctly for complete compatibility with the LM3886, as noted on the datasheet. The LM2876, LM3876 and LM3886 are all fully drop in replacements as long as pin 5 is connected for the LM3886. Pin 5 is a NC for the others.

All of these amplifiers will drive 4 ohms fine but at reduced output power. Notice the spec. no Output Current Limit in each datasheet, LM2876 = 3A, LM3876 = 4A, LM3886 = 7A. Two things are going to limit output power at 4 ohms, current and heat. For the LM2876 and LM3876 there is not as much output current aviable so output power is going to be lower. This is not a problem with the LM3886. Output power is directly related to die size and the larger the die size the better thermals are in the package so larger die can handle higher power dissipation. If you are planning on driving 4 ohms use the LM3886. If doing 8 ohms either of the others will be fine. National test with sine waves so the recomended voltages and output powers in the tables are pretty much worse case. Running music (although a sub it more demanding) is less stressful than sine waves. Check out the Overture Design Guide National has on there web site here--> http://www.national.com/appinfo/audio/

Gives you some good info on designs. Helpful in determining what you need for voltages, heat sink, etc. Keep in mind that the thermals section is calculated using worst case sine waves. I have run amps higher than they say but only with music.

  Reply With Quote


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
LM3876 for guitar? Wynand Chip Amps 4 2nd November 2005 08:26 AM
LM3876 vs. LM3875 Wynand Chip Amps 3 12th July 2005 09:03 PM
Help with a LM3876 amp! (nOOb) Fizx Chip Amps 3 24th June 2005 07:22 PM
Lm3876 bobossa Chip Amps 1 1st March 2005 04:18 PM
hi - LM3876 problems... RichardA Chip Amps 7 14th September 2004 04:32 PM

New To Site? Need Help?

All times are GMT. The time now is 12:27 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2