Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Chip Amps Amplifiers based on integrated circuits

LM3886 Problems
LM3886 Problems
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 8th February 2009, 10:54 PM   #1
ooops! is offline ooops!  United States
diyAudio Member
Join Date: May 2007
Default LM3886 Problems

Before I get some well-earned "you should have known betters" from the group, I am aware that I did try to shortcut the process and am now paying the price. I had built an LM375 kit a while ago and had zero problems -- and now suffered from the arrogance of the lucky I guess!

I assembled a set of BrianGT LM3886 boards and a single power supply. When I wired everything up, I hooked the amp up to some old speakers and got a big turn-on thump and low output (music) level coming out of the speakers.

I couldn't figure out what was wrong so I tried to verify all the wiring. I wasn't clear from what I read on Brian's website how to wire the transformer so I found a thread regarding the wiring of a AVEL transformer into a BrianGT power supply board. I determined that I had swapped the orange and yellow wires on the AC2 connection.

I swapped the wires around and fired the amp up again -- this time nothing coming out of the speakers (no thump, no hum, no music, nothing). So I did what I should have done in the first place and followed Brian's direction. I measured the output of the transfomer and it is correct as is the output from the power supply board. What I do have is a significant amount of DC on the binding posts (440mV).

Any idea on what my next steps should be? Have I fried the ICs?

Thanks in advance.
  Reply With Quote
Old 9th February 2009, 09:02 AM   #2
audio1st is offline audio1st  United Kingdom
diyAudio Member
audio1st's Avatar
Join Date: May 2005
Location: Foxton, CAMBS..
Just swapping the Orange and Yellow wires with each other, will have no effect! If you now have the correct voltage readings from the rectifier board, you would have had the same readings before the swap.
The problem must have been on the Amp boards (or the connection to them).
  Reply With Quote
Old 9th February 2009, 09:09 AM   #3
pacificblue is offline pacificblue  Germany
diyAudio Member
Join Date: May 2008
Are you aware of the mute pin? It is not present on the LM3875, but needs a resistor to V- on the LM3886.
If you've always done it like that, then it's probably wrong. (Henry Ford)
  Reply With Quote


LM3886 ProblemsHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Problems with Chipamp (LM3886) BrianGT Puffin Chip Amps 46 25th June 2014 10:22 AM
anybody facing stability problems with LM3886 BA100 with 8 ohm subwoofer? rhythmdiy Chip Amps 1 31st October 2007 07:04 PM
Are two separate lm3886 = 2*lm3886 in parallel or bridge mode rs1026 Chip Amps 11 21st October 2004 11:24 AM
LM3886-problems joensd Solid State 5 24th June 2002 07:43 PM

New To Site? Need Help?

All times are GMT. The time now is 07:07 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio