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 28th June 2008, 11:03 AM   #1
diyAudio Member
 
Join Date: Jun 2008
Default LM3876 and 4-ohm drivers

I am building a Silicon Chip kit with the LM3876 chips - I'd lke to use a pair of car speakers (I have spares) if possible. An addition in the kit mentions using supply rails at +/- 28V for this.
If I use an 18+18 VAC transformer - should this give me the +/- 28V.

Given these speakers will be in my observatory - quite small, used late at night - so quite low volume - should using this chip with 4-ohm loads be a problem??

TIA

Lee
  Reply With Quote
Old 28th June 2008, 11:08 AM   #2
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
That should be fine Lee.
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 28th June 2008, 11:09 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
the 18Vac transformer should be about right.
__________________
regards Andrew T.
  Reply With Quote
Old 28th June 2008, 11:38 AM   #4
diyAudio Member
 
Join Date: Jun 2008
Thanks for the advice guys - my plan, at least initially is to use my iPod or laptop as source - should I expect to have to use a preamp??
  Reply With Quote
Old 28th June 2008, 11:44 AM   #5
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Expect the possibility!

I don't wish to be offensive but you say that you are going to play MP3 files into car speakers, so I don't know if quality is an issue here. If not, you shouldn't need a pre.
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 28th June 2008, 12:08 PM   #6
diyAudio Member
 
Join Date: Jun 2008
If I could reliably pick a 256kbps MP3 from CD I wouldn't play them! I'll see how it all sounds and tinker from there.....
  Reply With Quote
Old 30th June 2008, 11:26 AM   #7
diyAudio Member
 
Join Date: Jun 2008
Music!!

My amp (one channel so far) produced some music! Stoked! Small amount of hum also - although so far I've not bothered with trying to minimise this with star grounding etc.
It sounded surprisingly good, considering I had the amp board connected to a bare, cheapo, paper-cone woofer alone, without any crossover/filter....

The hum I had completely disappeared upon shorting the inputs, or connecting an ipod - is this hum then due to ground loops??
  Reply With Quote
Old 30th June 2008, 11:34 AM   #8
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally posted by astrodog
The hum I had completely disappeared upon shorting the inputs, or connecting an ipod - is this hum then due to ground loops??
was the input open circuit when the hum was detectable?
__________________
regards Andrew T.
  Reply With Quote
Old 30th June 2008, 12:05 PM   #9
diyAudio Member
 
Join Date: Jun 2008
Yes - hum only heard when input open circuit.
  Reply With Quote
Old 30th June 2008, 12:13 PM   #10
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
open circuit input is not a normal operating condition.
Ignore this.
__________________
regards Andrew T.
  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
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 01:22 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