gains with lm3886 - 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 8th July 2005, 08:42 PM   #1
diyAudio Member
 
Join Date: Jul 2003
Location: Berkeley, California
Default gains with lm3886

Hi-
I've made an amp with lm3875 and several prototypes using the same chip. I'm starting a new amp and the lm3886 looks interesting. I was wondering what gains people were using. The data sheet says that gains between 20-200 should suffice. My initial thought was to use a gain of 20 as I had with the lm3875.
Is there a general consensus as to what gain to use with the 3886? There are of course obvious tradeoffs, but I'm curious to see what others think.
Also, I've never used the mute feature before. Do people typically have a physical mute switch or use an analog switch IC with a simple microcontroller or mechanical switch for control?

Thanks,

Doovieman
  Reply With Quote
Old 8th July 2005, 08:53 PM   #2
diyAudio Member
 
Join Date: Oct 2004
A gain of 20 in OK. The gain is usually set bewteen 10 and 20. If you use a preamp with gain choose bewteen 10 and 13.

Very few builder I seen use any switch at all. You can use it for the little delay by using a resistor and caps.
  Reply With Quote
Old 8th July 2005, 09:01 PM   #3
diyAudio Member
 
Join Date: Jul 2003
Location: Berkeley, California
Thanks for the note. I'm not sure i understand what you mean with regards to the mute and a delay. Can you explain a little more clearly? Thanks,

Doovieman
  Reply With Quote
Old 8th July 2005, 09:19 PM   #4
diyAudio Member
 
Join Date: Oct 2004
The combination of the mute resistor and caps causes a very small turn on delay.

The application note can explain it clearer
  Reply With Quote
Old 8th July 2005, 10:29 PM   #5
diyAudio Member
 
Join Date: Jul 2003
Location: Berkeley, California
Ahhhh, that makes sense.
  Reply With Quote
Old 12th July 2005, 09:09 PM   #6
diyAudio Member
 
Join Date: Apr 2005
Location: In the Wild, Wild West
Don't use a gain less than 10V/V on the LM chips and for best Noise performance keep the gain below 50V/V. If you need more gain then run a preamp that is high quality and reduce the gain on the LM3875 or LM3886 that you are using.

-SP
  Reply With Quote
Old 13th July 2005, 05:04 AM   #7
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Quote:
Originally posted by Doovieman
Thanks for the note. I'm not sure i understand what you mean with regards to the mute and a delay. Can you explain a little more clearly? Thanks,

Doovieman
If you check my QRP02 design (see my homepage) you can see how I have done the mute thing.

At power-up the LM chip is turned off totally under 12 V and over 12 V it starts to come alive but with shut off input stage which ends up in heavy attentuation. The datasheet has a diagram over current out from Mute pin vs. attenuation.

The result of my design is a completely silent turn on and since the buffers work under 12 V I have also a totally silent turn off.

I have used a bit higher value of the mute resistor in order to get a longer delay with choosed cap.

The mute and undervoltage feature is a really nice feature
__________________
/Per-Anders (my first name) or P-A as my friends call me
Tube Buffered Gainclone in work |Thread || Diamond buffer |Thread for the group buy | Wiki
  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
Different Gains Correction (VAS solution) Stee Solid State 2 8th September 2008 02:49 AM
Reading Rockford Fosgate Gains Flyin11 Car Audio 2 22nd January 2008 05:21 PM
Opamps and Gains mudihan Digital Source 14 18th July 2006 02:42 PM
how to compensate diffrence in amp gains in 3-amp system futiboho Solid State 7 15th October 2004 09:06 AM
doubling driver numbers/spl gains? RobWells Multi-Way 63 9th December 2002 03:31 AM


New To Site? Need Help?

All times are GMT. The time now is 06:30 PM.


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