Sample & Hold -> is this right to get a CV?

[brad]

I'd like to use a sample and hold as a control voltage, and found this really cool little circuit...

http://www.super-freq.com/wp-content/uploads/2008/03/bdm_sample_anf_hold.jpg

To get just the CV without the audio part, would I just use the section of the circuit going to R6 and into the FET?

[frequencycentral]

The opamp at the top forms a clock oscillator to turn the FET on and off.

The S/H happens between TL072A and TL072B. C1 is the 'hold' cap.

If you feed white noise into this circuit you will get a random voltage output.

So you need the entire circuit plus a white noise source.

[brad]

Arg!  Of course.  Thanks. 

[frequencycentral]

Have a look at the Maestro FSH.

This is my favourite S/H though: http://fa.utfs.org/diy/roland100m/schematicsshow18.html

[Franky]

This one is even simpler:

http://musicfromouterspace.com/analogsynth/singlechipsampleandhold/singlechipsampleandhold.html

[brad]

Whoa!  I like that one.  Makes me wish I had a use for the trigger output 

A midi clock input would be pretty interesting on a sample & hold I reckon.

[flo]

LF398, Sample & Hold with 1 DIL8 chip, $1.80 from Futurlec:
http://www.futurlec.com/Linear/LF398N.shtml
http://www.datasheetcatalog.org/datasheet/philips/LF398_2.pdf
Much simpler than a discrete build...