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 11th May 2003, 01:05 AM   #1
cowanrg is offline cowanrg  United States
diyAudio Member
 
cowanrg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, CO
Send a message via AIM to cowanrg
Default chip amp for infinity intermezzo 2.6

i just won a pair of infinity intermezzo 2.6 (powered bookshelves), and was wanting to build a chip amp to drive them. they woofer is powered, but the tweeter needs an amp. so basically, i would be JUST powering the tweeter.

i was wanting to use the LM3875, as i have a few of them sitting around. as far as the power supply section goes, should i use higher powered supply, to give better clarity, because ive heard (and experienced), with lower voltage supplies, the bass is heavier, but you loose detail. so im wondering if i should use a transformer with maybe 24v secondaries?

any advice? (oh, btw, these speakers DO benefit from good clean power. underpowered, they will sound a bit harsh, so i cant sacrifice TOO much power from the chip).
  Reply With Quote
Old 11th May 2003, 09:47 AM   #2
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Quote:
i just won a pair of infinity intermezzo 2.6 (powered bookshelves),
If they are powered why do they need a power amp?
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 11th May 2003, 03:48 PM   #3
elizard is offline elizard  Canada
diyAudio Member
 
Join Date: Mar 2003
Location: Winnipeg, MB
Send a message via MSN to elizard
the woofer is powered, the tweeter isn't (from his post)
  Reply With Quote
Old 11th May 2003, 03:59 PM   #4
cowanrg is offline cowanrg  United States
diyAudio Member
 
cowanrg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, CO
Send a message via AIM to cowanrg
re-read the first paragraph...

"the woofer is powered, but the tweeter needs an amp. so basically, i would be JUST powering the tweeter. "
  Reply With Quote
Old 11th May 2003, 04:09 PM   #5
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Yes, I did read that but couldn't see the logical reason for supplying a speaker with a powered woofer but nothing for the tweeter!

Is there a reason why the speaker comes like that?
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 11th May 2003, 04:16 PM   #6
elizard is offline elizard  Canada
diyAudio Member
 
Join Date: Mar 2003
Location: Winnipeg, MB
Send a message via MSN to elizard
yeah i know, that sounded strange to me too

but i've seen speakers like that before .. JBL and .. um .. blah .. another one, but i can't think of it now
  Reply With Quote
Old 12th May 2003, 04:08 AM   #7
cowanrg is offline cowanrg  United States
diyAudio Member
 
cowanrg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, CO
Send a message via AIM to cowanrg
its not an "active" speaker, its simply a powered speaker. who knows why both arent powered, but typically, the sub is usually just powered.

but in any event, any advice on my original question???
  Reply With Quote
Old 12th May 2003, 11:59 AM   #8
elizard is offline elizard  Canada
diyAudio Member
 
Join Date: Mar 2003
Location: Winnipeg, MB
Send a message via MSN to elizard
yes .. boston acoustic is the other company that comes into mind
just thought of it ..

btw sorry for jacking your thread ..

anyway .. peter recommends 22V for the secondaries
i think that 22 should be quite sufficient, as 24 is closing in on the limit for the chips themselves afaik .. although you could probalby use 25-26 before the limit

22V gives you an approximate 38 watts into 8ohms ..
there was a graph somewhere .. that peter posted ..
its from the lm3875 data sheet, so you can check in there (if i can remember correctly, its at the end of the data sheet)
  Reply With Quote
Old 12th May 2003, 04:33 PM   #9
cowanrg is offline cowanrg  United States
diyAudio Member
 
cowanrg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, CO
Send a message via AIM to cowanrg
just so im clear on this one, is that 22v supply BEFORE the rectifiers, or after? (ie - transformer with 22v secondaries?)

if so, that would work out well. i could actually try 24v too, since i have the transformers to do so.

i may keep the speakers, or trade them in for the B&W 805's. who knows....
  Reply With Quote
Old 12th May 2003, 04:41 PM   #10
elizard is offline elizard  Canada
diyAudio Member
 
Join Date: Mar 2003
Location: Winnipeg, MB
Send a message via MSN to elizard
sorry, my bad

it is before rectification ..
after rectification it provides you with about 31V i think

with 24V secondaries you should get about 34-35V, so you would be getting about 57watts or so ..

maximum voltage (listed in the datasheet) is 84V, so 42V rails ..
with 34 you're pretty safe i'd think
  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
Infinity 2 ohm 6x9's.. anyone? ThSpeakerDude88 Car Audio 0 10th May 2007 12:30 AM
FS: Infinity 6x9, 2 way car speakers Stuart Easson Swap Meet 0 8th August 2006 01:06 AM
Pioneer DEH-P8600MP, Infinity Kappa 693.5i, and Infinity Reference 6402cfp, and more jawglasswell Swap Meet 0 13th March 2005 07:38 PM
Infinity, JBL or other? ElectroPower Multi-Way 0 18th December 2004 06:57 PM
T-S's for Infinity MikeFarad Multi-Way 0 13th March 2004 04:23 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 © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2