chip amp for line arrays - 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 12th November 2006, 08:12 PM   #1
zhar is offline zhar  Canada
diyAudio Member
 
Join Date: Nov 2006
Default chip amp for line arrays

i have a wonderful set of NSB line arrays that i have set up in a bi-amped configuration.

i have been looking into building some chip amps for some time. the only problem is that i have read that chip amps dont like dificult loads. my line arrays are running around 98-100db so power isnt really a problem, but i have read that they will be a very high inductance load. is that a problem?

the chip i am planning on using is the lm3887 and i am planning to get a SMPS to drive them. and as i am biamped, i will need to build 4 of them.

if you know of anyone who has done a set up like this before, please point me in their direction.

As always, thanks for your advice in advance

Zhar
  Reply With Quote
Old 13th November 2006, 12:39 AM   #2
diyAudio Member
 
Join Date: Jan 2006
Location: Wisconsin....what did you expect?
Send a message via AIM to Spasticteapot
Default Re: chip amp for line arrays

Quote:
Originally posted by zhar
i have a wonderful set of NSB line arrays that i have set up in a bi-amped configuration.

i have been looking into building some chip amps for some time. the only problem is that i have read that chip amps dont like dificult loads. my line arrays are running around 98-100db so power isnt really a problem, but i have read that they will be a very high inductance load. is that a problem?

the chip i am planning on using is the lm3887 and i am planning to get a SMPS to drive them. and as i am biamped, i will need to build 4 of them.

if you know of anyone who has done a set up like this before, please point me in their direction.

As always, thanks for your advice in advance

Zhar
There's the absolute overlill solution.

Use one side of a LM4780 for every four or so drivers. This would also make EQing them a bit easier.

Alternately, you could sell me a few drivers off of each side .
  Reply With Quote
Old 13th November 2006, 02:27 AM   #3
zhar is offline zhar  Canada
diyAudio Member
 
Join Date: Nov 2006
that sounds like it would be an awsome project to do, but i jsut dont have the expertise/time/money to come up with a setup like that.

although it does appeal to the overkill freak in me
  Reply With Quote
Old 16th November 2006, 07:57 PM   #4
diyAudio Member
 
Join Date: Oct 2002
Location: France
Hi Zhar,

NSB line arrays, biamped . I have a couple of boxes of NSBs waiting for me to start a similar project. Could you tell us more about your line arrays? Maybe in the speaker forum or PM directly?

Cheers,

Exipnos
  Reply With Quote
Old 16th November 2006, 09:47 PM   #5
diyAudio Member
 
Join Date: Jan 2006
Location: Wisconsin....what did you expect?
Send a message via AIM to Spasticteapot
Actually, it might not be as hard as you might think. LM4780's are cheap, and when both halves are run in parallel (they're essentially dual LM3886s), they can drive 2 ohms.

The more drivers you have in paralell, the lower the inductance. (It goes up when you run them in series, of course.)

If the NSBs are 8 ohms, I'd put them into paralell sets of four, each run by a 4780. Alternately, do a series-parallel array; I'm pretty sure (if I remember my math right) that a 2-series by 4-parallel group would actually have half the normal inductance overall, while still being drivable by a single LM3886.

If you have 16 per side, you could use 2 LM4780's, with one half of each LM4780 for the top 8 drivers per channel, and the other half for the bottom. Inductance should be roughly 1/2 that of a normal driver, I think, and 4 ohms is ideal for a LM3886/LM4780 - plus, you can adjust the top and bottom halves seperately.

For the power supply, I'd reccomend a humongous transformer. If 2 LM4780s are used, 330va is an absolute minimum, with 400va being a bit safer and 500 + VA being ideal if you want to run 'em hot.
  Reply With Quote
Old 18th November 2006, 05:48 AM   #6
Fenris is offline Fenris  United States
diyAudio Member
 
Join Date: Jun 2004
Location: The last frontier
I'm working on a similar arrangement right now. 16 NSBs in a 4 x 4 series/parallel open baffle arrangement, 7 Dayton planars in a 3/4 power taper and two Peerles 8" DVC woofers with a Linkwitz transform. Actively crossed at 125 and 3000 Hz, IIRC. It uses 8 3886 boards from BrianGT and four power supplies. The 4 x 4 NSB arrangement means that you have the same resistance and inductance overall as a single NSB - not a particularly difficult load to drive. Make sure your 3886 has a zobel and you should be fine.

I haven't touched my amp in about 5 months. I've finished the case, inputs, volume controls (master, tweeter, and woofer), crossovers, Linkwitz transform, PSUs, amps, and speaker terminals. I only have to sort out the 120 VAC stuff - soft start and Bulgin power switch. But that has to wait since I'm overseas for the next month.

Here's a picture of the line array:
http://img.photobucket.com/albums/v3...tanis/line.jpg
and the back:
http://img.photobucket.com/albums/v3...anis/line3.jpg
and the side:
http://img.photobucket.com/albums/v3...anis/line5.jpg
__________________
Listen to the music through the stereo, not the stereo through the music.
  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
Thought experiment ... chip-amped active line arrays? Brisso57 Multi-Way 2 28th June 2008 09:55 AM
NSB line arrays for PA use? Spasticteapot PA Systems 1 1st April 2007 12:32 PM
Do line arrays... LizardBrain Full Range 4 23rd March 2006 05:21 AM
Line Arrays Down Under deaf monkey Multi-Way 0 14th December 2004 06:03 PM
Line Arrays Won Multi-Way 33 10th February 2002 10:20 PM


New To Site? Need Help?

All times are GMT. The time now is 11:57 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