[sdiy] Expo-Con

[David G Dixon]

> >Incidentally I would be curious to know how others are 'tuning' 
> >synthesizers these days (my favourite is reference beating 
> and 'listening' 
> >(have strobe tuner and counter...)

I use a Chinese cheapo Victor 921A pocket multimeter with a frequency
counter.  I have benchmarked it against an expensive Fluke frequency meter,
and it is spot on.  I paid about $20 for it at a local store, but you can
get them online for about $12, I believe.  That, and an octave generator in
the form of a 12-throw rotary switch with a chain of hand-matched 10k
resistors and the output buffered through an opamp.  This device generates
1-volt increments well within +/- 1 mV, and can be customized to work with
either 12V or 15V supplies.  We use those to calibrate all of the Dixies,
Rubicons, and Atlantises (and Korgasmatrons, Dr. Octatures, and uVCFs) at
Intellijel as well.  It takes about half an hour to go through a string of
100 resistors and find 11 that all read the same resistance to four digits.
I just buy 100 resistors on tape and put a little felt-tip dot on the tape
next to the ones that read 10.00k.  Then I just go and harvest as many of
these particular resistors as I need to make a switch.  I suppose that I
could buy 0.1% resistors, but I'm too damn cheap.