multi channel LM3886 amp??

[mrnedrub]

HI .I am wanting to put together a 5 channel LM3886 amp. Im also thinking about putting in an extra channel so I can play with active speakers at a later stage with out any pulling apart and modding. I have a couple of yamaha pa amp case(mass heat sinks!) they also have the huge torri aswell. I think its for 80volt rails? I have one yamaha that I have referbed with nice new 8mm thick front pannel and new internal wire/new caps and new power cord etc. I want to use the same case style and make the multi channel to match. The referbed amp that I have is now used for daul subs that Ive made.
So l was hopping to find a diy single side pcb for a lm3886 and power supply , then get the parts ....oh my goodness this is going to take for ever and I live in the country! (just love the cost of petrol eh!) So I was thinking about putting 6 chip amp kits from audio sector or chip amp. I am not sure who has what and what would be better but I do like the idea of having the parts and p.c.b manual etc all in one kit. So should I have one transformer and a single power supply or multi transformer with multi secondry and multi bridge/diode.......OK IM LOST!!

So can anyone suggest some options maybe along the line of "if your on a budget" to "maybe more costly but IMO worth it" type thing. As with most things in life, peoples ideas and experiences can often save much heart ache and $$$$$$.

Thanks to all

[mantisory]

here's a start:
900W LM4780 Gainclone

[aznshadoboy77]

First thought is that 80V is kind of high for rails?

[AndrewT]

build a simple AC coupled 3886 first.

Find out why it works and how to make it work badly.

Then you are ready to build a two channel chipamp. This will not work as well as the first monoblock, but your experimenting to try to achieve monoblock performance will teach you a lot and thus help you partially solve the problems of the multi-channel monster you desire.

Q:
how many drivers are in each speaker box?
Q:
why do you want a multi-channel amp with more channels than you have drivers?

[mrnedrub]

Soryy not to answer but biop took a little longer!! But back to the Main subjet. lm thinking about putting 3 stereo pairs for 6 ch amp and putting caps trannies (3) in own case and the amps diodes in another. Is it better to put the diodes in with the trannies or not? l would love to put six trannies so there would be mono style channels but the cost is restrictive and lm not sure the sound inprovement would justify the cost. l was going to make a 5 chnl amp for 5.1 dolby dig and then thought that l should build an extra chnl so if i wanted to use extra chanl later that it would be onboard and working already. lm also hoping to get a saving by buying more than 1 .....can only hope??!!
The only other thought was to put in AUSSIE AMPLIFIERS NX-150 amp modules. Not sure what to do really? The amp is for powering 2way monitor with ave impedence. The reason for thinking about use of AUSSIE AMPLIFIER module was for extra headroom but lm not sure of how much extra the costs would be over use of LM3886. Thanks for all the great thinking and advice its much appreciated . Shaun

[AndrewT]

Hi,
where are the 5.1 speakers?
I reckon the amps should be beside them.
That will not suit a one box solution for a surround sound system.

It is cheaper and simpler to run line level connects around the room that to run speaker cable that far.
Both the speakers and the amplifiers perform better with very short speaker cables.

[pacificblue]

If you build a six-channel amplifier for 5.1, there is no extra channel left. 5.1 means 5 surround speakers plus 1 subwoofer.

[mrnedrub]

Sorry perhaps l wasnt to clear. lwant to use the amp for 5 chnl for the surround LCR and LR rear and l use a seperate 2 chnl amp yamaha(2 by 400watt) for a pair of subs. l want to use a pre only processor . So my idea was to build 5 chnl amp but then l was thinking to try and future proof it(for 6 chnl) and the idea of building a sixth chnl even though l wouldnt be using it came about. l dont like going to the trouble of building something only to muck around with it later and undoing all the work you have put into making it look "right". l have found that most of the time the things that cost the most in life are the thing that you do twice! Also you can see where you have been and changed things around most of the time so "build once and build well" is a motto l try and stick with. With this in mind l was thinking that if l used 3 stereo amps like S.K.A / AUSSIE AMPs / etc in one amp box and then the 3 power trannys and the 3 rectifiers-caps in another box? Or as l said before 6 chip ampLM3886(mono) amp modules and the trannys/power supply in another box. l would love to build using one trannie and one power board with the individual rect/caps on it. l suppose that would mean a custom tranny then? l know little about transformers and whats possible and whats not so any thoughts would be gratefull.

[pacificblue]

Originally posted by mrnedrub
With this in mind l was thinking that if l used 3 stereo amps like S.K.A / AUSSIE AMPs / etc in one amp box and then the 3 power trannys and the 3 rectifiers-caps in another box? Or as l said before 6 chip ampLM3886(mono) amp modules and the trannys/power supply in another box. l would love to build using one trannie and one power board with the individual rect/caps on it. l suppose that would mean a custom tranny then?

Not a custom transformer, only a big one. Each of your possible configurations has its advantages and disadvantages. Six mono amps will be easier to build, most flexible and have a slight edge, when it comes to the sound quality, but will be the most expensive and need the most space. The solution with one transformer might be the least expensive, but will be the most demanding to build and the least flexible later on. E. g. it does not give you the possibility to switch unused channels of, if you use it to listen to stereo instead of 5.1. The version with three stereo amps is somewhere in between.

[chevy2410]

You could do what I've done and use two chassis and put 3 Lm3886 amps in one chassis and the other 3 in another chassis. Lots of wiring, but well worth it.


Chevy