hey, thanks for the fast response
of course this weird pulsating noise comes just with effects on, sorry when i wrote it maybe a bit confusing.
i tried several power supplies:
- usb-keyboard
- mac/pc via usb
- regular power connector with 9v-block-battery
i also thought about this first after reading a bit in the forum so i taped the power connector to kind of "isolate" the power supply
soundcloud.com/sodylicious/fehler-arduino/s-AxNQT
the above by soundcloud linked audio file shows you what happens when the device is connected and effect on without input. the change in freqs. is done by clicking the small black buttons
i also checked the checklist you send
1) definitly a arduino uno
2) order of connectors correct
3) caps placed correct as far as i can say from the instructions
4) ic placed liked shown in the 5 steps tutorial
5) solder points dont look like mechanical manufactured but should be ok
for the points of troubleshooting:
1) power supply check: tested with multimeter different spots on the pcb also on the ic, looks fine from this part
2) output stage works as described in the troubleshooting
3) the problem seems to be somewhere between input and ic i guess... may be wrong
4) tried with 3 different arduinos (2 are completly new, 1 reused)
thanks for reading and maybe some feedback