Help with LM386-based guitar amp.

  • Thread starter Thread starter rnelson
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rnelson

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HI all.

This is really my first diy project ever. Im trying to build a small battery-powered guitar amp using a lm386 IC amplifier.

I got the idea and schematic from make magazine's crackerbox amp.
link here:

http://makezine.com/09/crackerboxamp/

My problem is I get no sound at all out of the amp. I tried it first on a RadioShack PCB and I assumed it did not work because of some soldering error or something weird (im still new to all this but Im getting better at soldering).

Sso next I tried the same thing on a solderless breadboard and still no sound, I dont know whats going on. Ive tried it with a 16ohm, 75w celestion speaker. and a tiny( 3 inch diameter) 4ohm speaker. None of the two give me any sound. Yet When making contact with battery poles they both click so im assuming they work fine.

I have taken the liberty of posting some pics of my breadboard with everyrthing plugged in so hopefully someone could tell me what Im doing wrong. Keep in my the problem may be very, very obvious and stupid since I am a newbie at all this.

Any help would be very very appreciated, Thanks!

pics here:

http://profile.ultimate-guitar.com/rnelson/pictures/

there are some pics of the circuit for my actual guitar amp, ignore those, the first two are of the lm386 breadboard.
 
power is not connected this may help
Breadboard-144dpi.gif


thats how the breadboard is wired so by this we can see 18e and 19 e arnt connected ground and power also arnt connected the capacitor e24 and f 24 also arnt connected hang on and ill show you how to rewire it
 
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thanks so much for your help doulos!

I really see things a lot clearer with the schem you posted.

I rewired the whole thing and I think I am getting power now because the speaker pops if I graze the battery against the battery jacks in the PCB.

Still no sound unfortunately. Im thinking maybe the jack might be incorrectly wired but I have no way of knowing this simply because Im not sure what the correct way to wire it is.

anyway, I have posted some updated pics at the same place:

http://profile.ultimate-guitar.com/rnelson/pictures/

you think you could give me a hand once again? Sorry for being so newbiish, its just that Im well, a newb, hehe. I would really appreciate it if you could take a look and tell me whats wrong. In the meantime Ill try different solutions and post updates as I discover things.

Thanks!

EDIT: I am using a stereo 1/4" jack for the input. Do i need to wire al three terminals? if so how?
 
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the 220 uf is reversed the + side goes to the resitor the negative side does not go to 9 volt + but just to the first pin of the volume pot c1 the .01uf cap needs to go to a diffrent open hole if you put them both on the same row they short so a diffrent hole not next to anything else thats input on your jack
 
thanks for your help dude.

I already figured everything out and the amp is sounding cool as hell.

thanks again!
 
what doulos posted is the same as the Little Gem mkI by runoffgroove.
that's been upgraded by those guys with a fetbuffer to take pedals a bit better etc.
probably long overdue but these do sound fantastic as well..

try www dot runoffgroove dot com/ruby
and www dot runoffgroove dot com/littlegem
 
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