Ok. I’ve had a think about this circuit and all my guitar electronics ‘spidey senses’ are tingling.
Can I suggest the following.:
Sorry. That’s all I have for now
Thanks for taking a look dude - really appreciate it! The hum still occurs when an instrument or piezo are plugged in but not a synth or ipod etc. Not sure why this could be… Either way, still does the job! … Btw, does yours amplify the sound quite substantially even when turned down? I cant really push mine above half way without it distorting. It also still gives a fair bit of gain when turned right down.
Ha, always listen to the spidey senses! …All sound like good tips. One question - what do you mean by ensuring you have only one ground and all grounds lead to the main one? Whats the difference between this and just having the grounds all linked together?
Sometimes when laying out a circuit you can create ground areas that are separated from the ground on the power supply, say by a component or switch and form a second ground or end up with a ground line that’s not fully or properly connected - annoyingly this can seem to work sometimes. Think Lord of the rings: “one Ground to rule them all and in the darkness bind them” @analogoutput, @Caustic help! I’m not explaining this reverse physics (aka electronics) too well.
Im no expert. Hell, ive had many issues fixed as a result of improper grounding. I usually use the ground from the power supply since the same reference will be shared across everything, and it just sounds sensible to me. I just either wire up the grounds separately or use a ground plane.
I reckon I should pull my one out and recheck against the layout.
Mine definately works with an electric guirar no more hum than usual.
I’lll recheck my stripboard with the layout and post pics of my board tomorrow