New stuff for my modular patchable squarewave synth!

First: I finally got around to building a VCF. Its Ray Wilson's (Music From Outer Space) design from his Weird Sound Generator (which I originally found through Fluxmonkey). It is probably the most complex circuit I've built so far, but it was worth the struggle!

Second: I built an echo module by modifying a Barbie Karaoke toy. Again, most of the hard work was done by Pete Edwards of Casper Electronics. My Barbie Echo Module has three pots for echo pitch adjustment, one for decay, and one for feedback. I still have to built a power source for it, though, as it runs on 6 volts and my synth runs on 9 volts, and I only want to have to use one wall-wart when the thing is finished.

Third (and Fourth): I built two Passive Tone Control/Filters. I was introduced to the Passive Tone Control through Getlofi.com (I think), which had a video of Properboy's PSC stomp box thing. Then I found this schematic and decided I had to build two. It is such a simple little thing but the control over tone is fantastic. It acts very similar to a bass/treble balance.

Here is another example of how things are sounding. In the "song" two oscillators are going through the Barbie Echo and then through the Passive Tone Control. The third oscillator just goes straight to the mixer and evidences how the echo and Passive Tone Control change the sound.

Playing with the Passive Tone Control and Barbie Echo. by RA Isle

Up next is a sequencer, another VCO, some dividers, some better mixer controls, CV/gate input for the VCF, a two-band pass filter, and so on and so forth. Oh, and the "keyboard" and rack and... So much to do!