schematicssound
I'm trying to make simple sound-mixer. I've found this scheme.
Can I connect passive-pickup guitar to MICRO input? Which holes has that scheme? And can I increase inputs by just copying existing.
P.S. I'll miss phones-output block so as I needn't him.
A Piezoelectric sensor is enough for the detection of a kick.
http://en.wikipedia.org/wiki/Piezoelectric_sensor
They are cheap, easy to attach to a shoe and you can even use it as a buzzer to produce the sound.
This simple circuit will help you:
http://www.discovercircuits.com/DJ-Circuits/motionalarm2.htm
That will probably work well enough. Most devices are going to output a average level of 0, and 4.7 kΩ is high enough that I don't think any device will have trouble with it. This method will allow the other signals to back drive each output a bit, but at 4.7 kΩ that is unlikely to be a problem.
For extra security, you could put 2 µF caps in series with each resistor to guarantee DC blocking. 2 µF and 4.7 kΩ have a high pass rolloff frequency of 17 Hz, so won't cut into your audio.
Best Answer
No, a passive guitar pick-up needs a high input impedance amplifier. The "micro" input has an input impedance of 1 kohm (if I read your diagram correctly). The OPAMP is configured as an inverting amplifier with a gain of 100 and the 1 kohm resistor connects to what is known as a virtual earth (or ground) so, the 1 kohm is, in effect, from input to ground. You need to look for a guitar pre-amp circuit that has an input impedance of 100 kohm or greater. There are plenty of examples around on the internet such as this one: -
Notice the high value input resistors. If you use low value ones, you greatly attenuate the high frequencies produced by the pick-up and the sound is muddy.