New EFM

[>>>marjan<<<]

> PUT VCO
> http://www.xavax.com/efm/pdf/put-vco1.pdf
> Interesting but almost useless VCO. Interesting because it uses a Programmable
> Uni-junction Transistor. Almost useless because it has a limited 30Hz to 2.5KHz
> range and goes flat after 3 1/2 octaves. If you wanted to build a two octave "toy"
> synth this might be ok....I based this on my first successful VCO (the VCO-1) and
> I am fairly disappointed with the results. The VCO-1 has a 2Hz to 20KHz range
> and is good for 5 octaves. Unfortunately it uses a now rare and expensive 2N4853

I believe you can sub it with two matched trannys (as all 4-layer
thingies)
and it works :) Not shure about the range, but I know I had tried it
long
time ago. There's also trick to make it with LM3900, see NS app
datasheet for
LM (AN-72?). 


Also interesting 4qd's site: 
http://www.4qd.co.uk/ccts/putpr.html