Hi there!

I am a musician looking for a specific effect, and not sure how to achieve it.

I would love to take the signal from one microphone, and use it to affect the amplitude of a totally different signal (from a different microphone)

ie: amplitude of signal 1 = amplitude of signal 2

For various reasons, it must be an analogue signal, and not digital.

As I understand it, a transistor is a switch, activated by applying a small voltage.

I have been reading various websites, and need to check that I have correctly understood: Is there a transistor known as a "beta type" which is not only "on" or "off" according to the applied voltage, but can be progressively more or less on, like a water tap?

If this is so, my intention would be to use the voltage produced by a microphone to determine the state of the transistor, which will be controlling my second microphone's volume. Is this feasible, and will I need other things in the circuit to get this to work?

Thanks to anyone who is kind enough to reply :)

The heart of most amplifiers is a big power transistor, or one for each channel. Often it is a pair. It has 2 inputs, the signal, and the power supply, and an output. If you apply the microphone you want to control the amplitude of the other to where the power usually is applied, and the other to where the signal usually goes, the signal should vary with the first signal.

Cool, thanks labman... I intend to torture the neighbours with lots of cool noises thanks to you! Heheheh. The music cometh!

Ok.. cheers Labman, I tried that and it worked, sure enough :)

I am now going to ATTEMPT to build myself a unit with 7 "trigger" inputs, 7 "signal" inputs and 7 outputs.

For each input:signal:output, I am planning to use a single BC184L transistor, since they are available and suitable at the same time. It would make sense for me to use a 12v DC power supply since I have an entire box full of 'em.

For pose-value I am adding a couple of LEDs before the base and collector sides of the transistor. My question is, what resistors will I need?

I had in mind a 10k for the base and something smaller (naturally) for the collector. But I am still discovering the maths of electronics for the first time and am a little usteady on my feet, so to speak :)

Is 470 ohm way off-base?


I have a funny feeling I have a lot of blown components to look forward to, lol

470 ohms might be a good place to start. Different LED's have different power requirements. I looked, and I have a 270 ohm one with an LED I use for trouble shooting 12 volt systems. Good luck.