A simple stereo amplifier based on C3856

Thread Starter

tcdk

Joined Jan 7, 2009
23
Hi

I would like to build a simple stereo amplifier with only input/output, volume and on/off @ 2x50-80w (at least)

I have some C3856 and A1492 laying around that I thought I could use for the project.

I've searched through google after a schematic using C3856 (or similair) but haven't found anything yet.

Does anyone have a schematic or something that I could use?

Thanks
 

beenthere

Joined Apr 20, 2004
15,819
If that's a 2SC3586, it's not gonna be easy. The transistor is rated for UHF and microwave amplification. Audio amplification would be an unusual application.

You can always try it as a substitute for another type in an existing design.
 

Thread Starter

tcdk

Joined Jan 7, 2009
23
If that's a 2SC3586, it's not gonna be easy. The transistor is rated for UHF and microwave amplification. Audio amplification would be an unusual application.

You can always try it as a substitute for another type in an existing design.
It's a C3586. I got it from a Akai stereo amplifier that died.
 

beenthere

Joined Apr 20, 2004
15,819
The number C3586 turns up things like furniture. It may be a non-standard transistor, and so will be impossible to get specifications.
 

Thread Starter

tcdk

Joined Jan 7, 2009
23
Thanks!

I can't find any with the specific transistor, but found this one very interesting and easy.
http://sound.westhost.com/project19.htm

The LM3876 chip is also pretty cheap :)

Eg. @ futurlec.com the LM3876T is statet as "40W High Perf. Audio Amplifier"
and other places as 56W - should I make any differents in the layout if or is it the same?

 

Thread Starter

tcdk

Joined Jan 7, 2009
23
What kind of transformer would you use for a amplifier like that? (35V)
I found Hammond 266K35, but don't know if that will do.

And where should I buy parts? I normaly buy from futurlec.com, maplin.co.uk and mouser.com - but no one have both the LM3876 and a transformer that suits....
 

beenthere

Joined Apr 20, 2004
15,819
Transformers are quite expensive - can you get to some sites that offer surplus items? Don't forget you need the current as well as the voltage. A 24 volt transformer will give close to 35 volts DC after rectification with good filter caps.

You can always refigure resistor values if you go significantly up in voltage - say, 42 volts instead of 35. Your output transistors will handle the power, so see what transformers you can scrounge up and work with it/them.
 

Thread Starter

tcdk

Joined Jan 7, 2009
23
I just found out that I had a 40V transformer from a old amp.
I altso has a several ~36V outlets to :)

There was also a pretty large heatsink, some RCA chassis jacks, speakerouts and more.
Yummy!
 
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