Let's Make Robots!

Cracker Box Amp has static-looking for suggestions

Hi... I just finished building an amplifier, a CrackerBox Amp, from plans from Make Magazine. I hooked it up to my Ipod and the circuit seems like it wants to work except it has a lot of static.  However, when I hold one of the arms of the rheostat and hold, in my other hand, the Ipod, it actually works pretty well, with no static.  I'm wondering if anyone can shed any light on what might be causing the static.  I've posted a picture of the completed circuit and a video of the unit.  thanks for the help.

John

AttachmentSize
crackerBoxamp.jpg131.02 KB

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Well.... after doing some inspection I found a broken wire in one of the jacks.  Reattached it

and .... lo and behold, thing works like a charm.  The sound quality is actually pretty good, very surprised.

But thank you all for the help  :-)

i think you need a connection from the rheostat case to ground on the amp or something like that or the ground on the jack is not connected to the amp correctly  

Yup ground the back Of the rheostat

thanks for the suggestions.... I'll take a look and see if I can find anything suspicious.

Usually it's a dirty connection to between the source and the amp with a 386, though that chip has a worse and worse reputation with hackers.  Look at the plugs and jacks for shmutz and bridges.