8 X LM3886 design sought

[gary h]

Hi all,

my next speaker project is an actively eqed design and will require 8 modest (~50W) amps to drive all the speakers. This LM3886 design has been recommended:

http://www.national.com/mpf/LM/LM3886.html

I am a newbie at amp building. I'm wondering if I can incorporate 8 amps with 8 power supplies in one chassis and use one transformer. Basically I'm trying to consolidate the package. If there are any designs available or anyone with experience with this kind of project I would appreciate some advice.

thanks,

gary

[tangmonster]

Is it just one speaker?

What are the speaker impedances? How many chipamps per speaker?

You have to give more info.

[elnec]

Originally posted by gary h
Hi all,

my next speaker project is an actively eqed design and will require 8 modest (~50W) amps to drive all the speakers. This LM3886 design has been recommended:

http://www.national.com/mpf/LM/LM3886.html

I am a newbie at amp building. I'm wondering if I can incorporate 8 amps with 8 power supplies in one chassis and use one transformer. Basically I'm trying to consolidate the package. If there are any designs available or anyone with experience with this kind of project I would appreciate some advice.

thanks,

gary

Hi gary,
i also making similar kind of project but only problem i am facing it of PSU , can u give me some detail on it

Regards
Elnec

[tiltedhalo]

A Chip, 3886 is an AB amp and achieves about a 60% efficiency so at 50W output you need between 70 and 80W's of supply. then multiply by the number of amps, 8*80W=640W+ 10% for overhead. Just find a trans in that range and away you go.

[elnec]

Originally posted by tiltedhalo
A Chip, 3886 is an AB amp and achieves about a 60% efficiency so at 50W output you need between 70 and 80W's of supply. then multiply by the number of amps, 8*80W=640W+ 10% for overhead. Just find a trans in that range and away you go.

hey tiltedhalo,
thanks for your suggestion good 700w PSU for this as i'm not able to find it .please tell me or give a link on schematic for this PSU

thanks in adv

regards,
Elnec

[jackinnj]

You can cut down the number of chips by using the LM4780 which is a pair of LM3886's in one package -- I think Peter Daniel or someone sells a PCB for this.

You won't actually need the theoretical max power unless you are using the chip to run servo motors in a laboratory -- saying this, however, a number of people are using the transformers from John Ango at www.antekinc.com -- they are now advertising in AX which means they support the DIY community. These trafos are really beefy -- for CNC machine use and a bit of overkill -- but the price is right.

Jack

[elnec]

Originally posted by jackinnj
You can cut down the number of chips by using the LM4780 which is a pair of LM3886's in one package -- I think Peter Daniel or someone sells a PCB for this.

Jack

Hi Jack,
first of all, i live in india & LM4780 is not available in india & so can u suggest any other alternative for this, your suggestion are welcome

regards,
Elnec

[jb74]

gary h, elnec

You might find interesting/useful information here:

http://www.linkwitzlab.com/xo_eq.htm

Near the bottom of that page under the heading
Power amplifiers

3886amp.gif
3886pwr.gif

[gtforme00]

I second the Antek recommendation. I purchased two of the 20V + 20V 600VA for my 12 channel LM3886 project. I used boards from www.chipamp.com for the LM3886.

PM me for more info, I might even have some extra parts laying around.

Regards,
David

[elnec]

Originally posted by jb74
gary h, elnec

You might find interesting/useful information here:

http://www.linkwitzlab.com/xo_eq.htm

Near the bottom of that page under the heading
Power amplifiers

3886amp.gif
3886pwr.gif

thank man