Keyboard circuit (was Stretch tuning a resistor string)

[Haible Juergen]

	>The only synth I know of that feeds the keyboard resistor string
with
	>a regulated voltage is the Moog Taurus I.  And that uses double
throw
	>keyboard switches.

And as it's V/Hz, I assume these are not equal value resistors either.
(The gif in front of me is too fuzzy to decide.)

As for V/Hz resistor strings, there is this brilliant Korg solution, which
works
with a voltage source:
Connect the S&H to the *end* of the resistor string, and use the key
contacts
to *feed* the voltage source to various positions of the resistor string.
(Hmm, yes,
it's not exactly a resistor string, but every second series resistor has a
shunt 
resistor to GND, so it's more of a Ladder than s String. But that's just a
clever
means to avoid a lot of different resistor values. They get the exponential
response
with just 3 different resistor values.)

JH.