4.02.2008

VactrolSynth_v.3 schematic


Here is the schematic for the 3rd revision of my vactrolSynth. It uses only one 4093 quad NAND gate chip. Try experimenting with different capacitor values for the control and audio oscillators to achieve various tonal capabilities. Note: this schematic omits a potentiometer before the vactrol LED... add this for a pseudo pitch control. Try to use a super-bright LED and a photo-resistor with a wide range for excellent frequency response.

9 comments:

felix said...

Awesome!

That's a rad idea for a schematic sketchbook too! Graphing paper moleskine and a stencil. :D

dalas v. said...

My goal in life is to one day be able to look at this and then easily build it. I'm only 28, so maybe within 10 years I'll have figured it out.

Intosia said...

Thanks man! Just saw the vid, love the sound, im gonne build one!

Fernando said...

Which vactrol are you using? Should I look for fast decay or slow decay? I have access to either a couple of VTL5C4/2 or VTL5C2. What do you recommend?

Thanks.

.alex_inglizian. said...

hey fernando: i make my own vactrols... so the decay depends on the nature of the LED. Choose a vactrol with a decay that matches the sound you seek... a longer decay will translate to a longer pitch envelope release.

Fernando said...

Thanks for the inspiration. Just started trying with generic, no spec sheet photo resistors I had lying around and all the LEDs I can get my hands on.

The sound is not as clean as in your video, but it is great fun to experiment.

Sunlight through the window in place of the LED gives interesting results, specially in lightly cloudy days. I will call this one a "sun harp".

Jan Dijkstra said...

Hello, we (my 14 year old and I) can't get the Vactrol vs 3 working.
Could you post or mail a picture of top & bottom of your v-synth?
Perhaps if we trace the wires we can find the mistake we made.
Thanks!

Jan Dijkstra said...

Problem solved: found another datasheet for the 4093, different pins on the IC.

Jan Dijkstra said...

http://www.myspace.com/tkradijs