Hey, thanks for the circuit! I'll whip one up tonight or over the weekend and give it a shot.
If the thing makes a buzzing noise, I'll try to find a workaround such as a strategically placed capacitor.
If not, I found this:
http://wps.com/products/Model-13/index.html
and, wonderfully, he has posted the code for it here:
http://wps.com/J/Sources/clock.bas
What he has done is use a PIC controller to drive the d'Arsonval movement directly, and it looks like he has gotten excellent results. His clock is far more complex, using the single d'Arsonval to display time and date! What a cool project!
Anyway, if I can't get a silent driver for the existing tach circuit, perhaps I'll just remove it and drive the needle directly with a PIC controller, and steal some of his code.......