** First post to avoid error message **
Hi everyone, I'm trying to control some rgb leds with the input of a microphone. Controlling the leds is easy, but I'm having some trouble with the audio amplification.
I use the schematic on the bottom of this page (which was recommended in another thread): link
The only difference is that I use another condensor microphone (datasheet) and a JRC386D as amp which I'm told is the same as an LM386n.
I removed the connection between In+ and ground, becasue connecting both In+ and In- to ground made no sense to me. (This connection is also not present in the photo on the page of the schematic)
Now I get base readings in the 400's and it peaks at about 800 when I blow into the mic. However, even how hard I yell, it doesn't seem to affect the readings at all. So it is doing something, but is not nearly sensitive enough to be affected by my voice.
Here's my setup: 
Have I made some stupid mistake here, or do I just need to play around a bit with the values of the resistors/capacitors? I don't wanna do that at random, so any thoughts on where to start?
Any help is appreciated!
I think you simply have not got enough gain. The 10K resistor will give a gain of 50, if you remove it and connect the capacitor directly across the two gain pins you will get a gain of 200.
Anyway this is not the right sort of amplifier for this application. This is a power amplified designed to drive speakers. What you want here is more of a pre-amplifier. I hate that site as it usually has very bad designs on it, but well explained, this is another one.
I removed the connection between In+ and ground, becasue connecting both In+ and In- to ground made no sense to me.
You are misunderstanding the drawing symbols, the In+ is not wiring to ground as there is not a dot at the intersection of the ground and In+ intersection, the In+ signal is just passing on to the pot's wiper connection.
Lefty
Thanks for the reply guys. I'll try to remove the 10k resistor to get more gain and see what happens.
What you want here is more of a pre-amplifier.
Would you perhaps know of such a circuit or have some links for reference material?
You are misunderstanding the drawing symbols, the In+ is not wiring to ground as there is not a dot at the intersection of the ground and In+ intersection, the In+ signal is just passing on to the pot's wiper connection.
Well, that would be the case in the circuit on top of the page, but if you look at the circuit on the bottom (the final circuit) you see that In+ is definetely connected the ground as the potentiometer is taken away from the circuit. But thanks anyway 
you see that In+ is definetely connected the ground
I see what you are saying. I told you it was a bad site with bad schematics.
Well, it seems you're right.. and it looked so reliable.
Anyway, increasing the gain to 200 didn't help, my base readings just keep fluctuating and it doesn't respond to sound at all.
So I just found another thread, in which the following schematic was used for a mic pre amp: link , but instead of using the OPA344 the guy used an LM324N, which I also happen to have. So i wanna try to build that one, however I don't quite understand the schematic.
What would JP1 be on the right? Why wouldn't I just connect the output of the opamp (trough a rectifier) to my arduino?
And on the far right there is a small capictor connected between the vcc and ground.. Am I supposed to connect the +5v and ground with this capacitor on my arduino? That seems odd..
Could you perhaps shed some light on this? Thanks!
edit: this is the thread I'm referring to btw: thread