Troubleshooot humming Noisy Cricket layout

[xylix]

Hi,

I built a couple Noisy Crickets earlier this year and really love the sound of these little amps. I ended up giving them away to people and recently built another one for myself. I have done all of them on perfboard with small changes. I am not 100% happy with the latest one. It has some hum that I don't remember the others having. Also the LEDs don't work. I have checked the original schematic and thought that I did everything correctly. Could some of your more experienced people have a look at my layout and see if there is something obvious wrong with it? I made a diagram of the layout in Illustrator - sorry for it being a bit messy.

Thanks,

Craig

[tonyharker]

It looks like you have missed the link between pin 1 of the Volume control and earth!

Tony

[xylix]

It looks like you have missed the link between pin 1 of the Volume control and earth!

Tony

Ah yes, I did miss that on the drawing. I had initially NOT wired pin 1 to ground, but did add a connection from pin 1 to ground after, but there is still a slight hum. (Major hum before.)

Craig

[joecool85]

It looks good to me, I'd say you might have a bad solder.  Go through and resolder all your joints and it may work better.

[xylix]

It looks good to me, I'd say you might have a bad solder.  Go through and resolder all your joints and it may work better.

Thanks for the re-assurance. I will check out the joints and resolder. (I probably also should have replaced the tip by now.)

Craig

[udtman]

Well, I was building a different 386 based amp and noticed a lot of hum, etc, well, i was using the 386n-1 ver which goes up to 9 volts supply,to make a long story short, ,i changed to the cheapo plain lm386 which is the 6 volt max version and all the hum went away.
I tested 3 different lm386n - 1's and got all the same results