[sdiy] 7555 as TOG for organ clone.

[Jon Philpott]

Hi List,

I'm looking into creating a transistor clone-organ using the
'classical' top octave synth + divider network. So far I'm looking at
using a 4024 for the dividers and a 7555 to generate the top octave.

The 7555 circuit I'm looking to use is fig 1a in:

http://datasheets.maxim-ic.com/en/ds/ICM7555-ICM7556.pdf
(1 resistor, 1 cap astable multivibrator, 50% duty.)

For the resistor i intend to use a base resistor(1.5k-5k with 0.22 -
0.47 caps) + 5k or 10k multiturn trimmer for the tuning, and i'm
looking into polyproperline for the caps.

Now I understand that with this design the frequency will be
temperature sensitive, but can anyone give me an idea of how
sensitive?  will it be usable? or should I look into a different top
oscillator source? Suggestions? :)

Jon.