Testing VCO - 2.0VDC
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Testing VCO - 2.0VDC

by orangefest on Sat Mar 16, 2013 9:23 pm

I'm currently building a Willzyx x0xb0x. I skipped over the "Testing & Calibration" section for the VCO since it says "The precise calibration step can be delayed until the rest of the synthesizer is completed, when you can just press a button to generate 2.0V and 3.0V to the VCO." I've finished building most of the synth, but don't know what this "button" is that switches between 2V and 3V? Anyone know what this is referring to? I don't have a variable power supply or a scope so can't test the 2V. Thanks.
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Re: Testing VCO - 2.0VDC

by synthplayer on Sat Mar 16, 2013 9:51 pm

The CV(control voltage) for the VCO is linear, key

C0 = 0V
C1 = 1V
C2 = 2V
C3 = 3V
C4 = 4V

You can check this voltage on IC11 pin 7. You should be in keyboard mode and you should get these voltages with the C key by going up and down the octave.
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Re: Testing VCO - 2.0VDC

by eject on Tue Mar 19, 2013 10:59 am

Wow, I have the exact same question.

When you say check the voltage on IC11 pin 7 what other point should I connect to verify the voltage?

Is there a step-by-step set of instructions for this?
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Re: Testing VCO - 2.0VDC

by antto on Tue Mar 19, 2013 12:17 pm

in this case set the multimeter to measure DC voltage, and connect the "ground" probe to a "ground" point in the x0xb0x (for example the heatsink on the IO board)
the other probe goes to what you measure (pin7 in this case)
We are here too: irc.freenode.net >>> #x0xb0x
..:: c0nb0x v1.00 ::.. http://forums.adafruit.com/viewtopic.php?f=7&t=29282 (new control app - win/osx)
VCO Tuning: http://forums.adafruit.com/viewtopic.php?f=12&t=24759 (do it the EASY way)

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Please be positive and constructive with your questions and comments.