Using one 9v input for 2 different effects in one enclosure

[Giguer101]

Hello, I have a problem. I decided to make a mini stereo guitar amp, using 2 little chip amp based on the chime amp. I soldered everything, but there's a ground problem I suppose. There's this annoying hum when I plug only one cabble and when I touch the second input the hum is almost gone but still there. I rewired everything and still the same problem.

Is there something I don't know about doubling 9V to power 2 effects with the same power supply. Is there a way to isolate the ground on each pcb?

First pic shows the schematics and the second is the two pcbs connected together (the blue line is the ground path)

[madbean]

Try ground the second input when not in use and see if that solves the problem.

[Giguer101]

Ground is connected to both input left and right. That's why I don't understand why there's a buzz... when I use only one amp at a time and unplug a speaker it works perfectly, but the goal is to have a stereo amp!

[wgc]

What are you connecting to left and right?

Shot in the dark, but try connecting pin 3 of u1 to pin3 of u2, and do the same with pin 6.

Wouldn't hurt to check all your solder joints and traces either.

[Giguer101]

I connect a pedalboard with stereo pedals(delays, reverb and a ditto looper x4)Tried connecting pin 3 and pin 3 but nothing changed, still a buzzing sound. I started from scratch a second time with 2 new guitar amps and still doesn't work like it should... I really don't understand. I don't know what to try... The pcb's were printed by OSH park, they work fine seperatly...

[wgc]

Is this boxed?  How are your speakers or speaker jacks mounted? Could it be you're shorting one input or speaker output somehow?

Also, what is the impedance of your speakers?

Put some pictures of your builds up.  It would help to see how things are mounted and wired.

Meantime it looks like it can be done

http://www.eleccircuit.com/small-stereo-amplifier-with-tda7052/

Looks like they added a cap to remove noise.

Anyway, I think it's a cool idea, but there's similar chips that are stereo and maybe better suited to what you want to do, aside from possibly needing a voltage regulator or having different output.