Q about building more than one synth circuit into a box...

[jamiewoody]

if you build 2 or 3 synth circuits into one box (lets say, a 555 based lumavox, a stepped tone generator and a schmitt trigger based synth), how do you tie them all together?

lets say each circuit runs on a 9 volt battery. would you use a separate battery for each? (i know you can build a voltage regulator and get power from the wall, lets say you want to use batteries anyway). if you do all three circuits from one battery, does that take voltage  from the other circuits?

what about output? once i build two circuits into one box, and the controls for each still worked on the other circuit, even when that circuit was switched off. the only common factor was they were both tied into the same output jack.

thoughts?

[lomax]

from my experience you have to power each circuit independently. i ran my 556 with a marshall micro amp and split the power... the circuit would play when the amp was turned up. it would stutter until it had enough power to amplify.

[Gordonjcp]

This is why the "anti-theory" approach doesn't work.  You need to learn a little about electronics to get these things working ;-)

[Circuitbenders]

Theres no reason why you couldn't power more than one circuit from the same power source. If you couldn't then modular synths just wouldn't work, in fact nothing would work. You could run everything from a 9v battery but it really depends on how much total current the circuits are going to be trying to draw. What i'd do is build a simple power supply with a voltage regulator and a couple of caps and power everything from there.

You need to build some kind of simple mixer circuit if you want to mix the audio from two circuits properly. As you discovered, just wiring the outputs together can cause some unwanted effects. Do a search on the forum or the net for mixer circuits and you should be able to find something simple.

[jamiewoody]

well, i tried building 3 circuits on one circuit board. i thought i did everything i needed to. they all worked, but the signal dropped quite a bit when others were turned on.

and yeah, i know that i need to learn more about electronics. i want to go to school for it, but i am trying to figure out how, when i have a house mortgage to keep up in the process...