Wednesday, January 5, 2011

Internal Voltage Divider Done - now get 1V/Oct

Here's a solution to get 1V/Oct - I just used a trimmer as a variable voltage divider to replace the external test V-divider I made before. I'm still tuning it right now, and the sweet spot drives the octave range up two full octaves (So note C3 = C5).

More spaghetti!

So (for novices like myself) I took CV in to pin 1 (could have gone to pin 3, opposite operation), the line the R7-south off pin 2 (the wiper) and a wire to ground from pin 3 (could have used pin 1, opposite operation).
Still, could have saved all the trouble with Silent Way!

Febuary 6th 2011 - Additional Info:
Here's the basic circuit for the voltage divider:

Instead of using two resistors for a fixed voltage divider, a single trim pot replaces both.
Then terminal 1 (or terminal 3) is equivalent to the Vin connection above. This will be the CV input.
Then terminal 3 (or terminal 1) goes to ground.
Then terminal 2 on the potentiometer (trim pot), which is the "wiper" terminal, is Vout above. This will go to south side of R7 if you did Din Sync's mod for CV input.
The interchanging of terminals 1 and 3 does not matter; the direction of operation will just be opposite for either choice - resulting in Clockwise (CW) operation or Counter-CW operation.
This circuit is based on the ratio of Z1 and Z2 (or R1 and R2 for resistors). Because of this, using two 10k resistors is identical to using two 100k or two 1M resistors, according to the following equation:

Vout = [R2/(R1+R2)]Vin
For the list of values above you will always get that Vout = (0.5)Vin.
With a trim pot you can "tune-in" the right ratio to get Gakken on 1V/Oct.

Note that this is the simplest case. To get proper V-division, you would have to know about the impedences of the circuitry connected to it.

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