Curios to see a schematic of this mod..
CB said..
For volume on the input i use a 4.7K pot with one side wired to ground, the input wired to the other outside pin and the centre pin wired to a SPDT centre off switch via a 1K resistor and 4.7uF cap. The other pins of the SPDT wire to the DCO 1 & 2 inputs on the 2069 chip so you can select the audio path.
attached below is a pic of the 2069's pins and signal paths to help with this discussion..
I was thinking it would be better to inject an external signal at where the noise source goes into the filter... at pin 7.
I suppose one could pull the IC out of its socket, bend pin 7 out (then reinsert the chip back into the socket.. Pin 7 sticks out the side) so you can attach a lead to it via a slipclip connector of sorts(or just solder direct to the pin).. connect that to a SPDT, then reroute the Pre-IC Noise signal to the switch(a wire from the PCB to switch).. the external audio brought in thru your volume pot/res./cap and then onto the SPDT.
This way DCO1&2 are isolated to either be on/off. The noise VCA can be used to digitally control the ext. inputs volume(post the input pot).. and of course the VCF envelope(EG3) will alter the ext. audio's tone... just like it does for the two DCO's.
I suppose I could use both the DCO signal inputs, but they both will use the same filtering(just like the noise signal uses)... if I use the noise input, I can keep the DCO's audible and not have to shut down their individual Osc. tones.. I can control the DCO's volume independent of the Ext. audio signal.
I think this would provide a better control to balance the DCO's with the Ext. signal.
I dont know about other users of Korg's, but I seldom use the noise source in patches. So I figured it would be better to select Noise/Ext. Signal rather than between DCO1/Ext. Signal or DCO2/Ext. Signal.
May seem a silly question, but where do you hook up the external signal's GND?