hi all.
I'm pretty new to all this and was wondering if anyone has fitted a lfo to the speak and spell to control the pitch.
Ive seen a few on ebay for sale and want to try to fit one to mine.
i have made a simple lfo using a 555 timer but don't know where to connect it on the speak and spell.
any help would be most appreciated.
thanks
Gary.
The speak & spell actually has some points on there that you can connect to a pot for a pitch bend without an lfo. Look towards the bottom of the machine on the left hand chip. Somewhere around there is the base and then there's a pitch up point some place near by and a down point. They're pretty well documented on the net, so you should be able to find photos.
Adding an LFO to a pitch control is great because you can control the rate/depth of the pitch modulation. Like a tremolo-y warble or slow waves of pitch jumping.
Casper Electronics has a great schematic for this:
http://www.casperelectronics.com/images/finishedpieces/speak-n-spell/Speak-n-Xbending/LFO%20schematic2.jpg
This was the first 555 LFO i built, and I've modeled a bunch of them off of this. Great stuff.