How inexpensive can you build a small 6-ch amp?

[mazeroth]

I'm looking to learn how to build amps and was wondering how much it would run to build a very small 6 channel amp for my computer's active speaker setup? I'm guessing I won't need any more than 5-10wpc, since I'll be about a meter away at most from the speakers.

Any information or links is GREATLY appreciated!

[joensd]

You could have a look at nationals calculator for "estimations" on what you´d need for rail voltage for specific loads.
For building a GC I like Nuuks site very much. Very well put together.

The cost determining factor will be transformer, chassis, sockets
(besides the amps/kits themselves) so keep your eyes open for anything cheap.
What about transformers for halogen lights?
Usually the´re dead cheap and would easily get you into the 10W ballpark.

http://www.national.com/appinfo/audi...gn_Guide13.xls
http://myweb.tiscali.co.uk/nuukspot/...loneindex.html

For the application a LM3875 would absolutely suffice, also with 4ohm loads due to the low rail voltages.
If you want it cheap do it P2P or get one of the "known" kits around here which are quite cheap as well. (got mine from BrianGT/Peter Daniel, as sourcing all the parts would have been more expensive)

[thespeakerguy]

Consider Class D Amplifiers.

For example, operating off a laptop type power supply, such as 16V 4A from an IBM thinkpad, you can do 10W into 8 ohms into 6 channels. Of course, not all channels would do this at the same time, so each channel can acheive reasonable power well within the power supply's capability.

One approach, 3 pieces of MAX9741, for the 6 speakers, the a single MAX9708 in mono mode for a subwoofer.

Total solution would easily fit on a 3"x5", assuming small 3.5mm stereo jack inputs, and small speaker terminals, not binding posts.

No heatsinks required

[sagarverma]

bridged lm358 for each channel

so u get 6 channels of 2w each(rms).net power is 12w rms.sufficient enough,cheap too.low cost of components,inexpensive heatsinks,low cost transformer,good quality sound output.
cost estimate<$10.

google shows many links for above application

[lohk]

3 x LM1876

[Gcollier]

Could try something like this! I used SMD resistors to cut down on the size as much as possible. The feedback resistor is just behind the pins on the LM1875 (again a 1206 SMD package). I designed a small little PSU to go along with these, nothing fancy a brige rectifier and a few caps. I intend on using them in a small speaker syster for my office at work, I plan on mounting them in a small extruded aluminum enclosure along with the transformer.

G.

[sagarverma]

lm358 fits your demands

[carlosfm]

2xLM4781

[sagarverma]

hey
grave mistake



its lm386 not 358.

highly regretted

[ocool_15]

[QUOTE]Originally posted by sagarverma
[B]hey
grave mistake

lm358 is opamp dual op i think I was rather confused by that statement. Everyones got some lm386s though