Help me to begin "DIY" modular synth ....(starting with an OSC)

[whyterabbyt]

for the Atari_Punk_Console_Kit , i don't really understand why there are CV if this inputs are not controlling the pitch !

sorry, I'd overlooked the fact that the Synthrotek version of the APC does have some 'CV' inputs. That's not the case in the 'pure' APC. From the schematics they seem to be connected to the CTRL and Threshold inputs of one timer of the 556.

Checking a reference page for the 555/556 tells you what those pins do

its even on t' Wikipedia:

CTRL Provides "control" access to the internal voltage divider (by default, 2/3 VCC).
THR The timing (OUT high) interval ends when the voltage at THR ("threshold") is greater than that at CTRL (2/3 VCC if CTRL is open).

Pin 5 is also sometimes called the CONTROL VOLTAGE pin. By applying a voltage to the CONTROL VOLTAGE input one can alter the timing characteristics of the device. In most applications, the CONTROL VOLTAGE input is not used. It is usual to connect a 10 nF capacitor between pin 5 and 0 V to prevent interference. The CONTROL VOLTAGE input can be used to build an astable multivibrator with a frequency-modulated output.

So, yes voltage control of something, but not 1V/oct pitch by any means; glitchiness as ghettosynth says.

These are the kind of things you'll have to learn to work out for yourself if you're going to design anything btw.

[hivkorn]

yep i'm not a pro

i think i would change the switch for a button to act like gate ( on the atari )

I will take my time to understand everything.I need to purchase so equipement to achieve it.
But as it seems to be a very hard time to understand / learn , i will finish my EP before and i will build the synth for the next one . thx for the help