Tuesday, November 22, 2011

CD4512: A Simple 8 Channel Selector

It's hard to pick the best ic in your growing collection of cmos. but the 4512 is one of my favorites.  One of the goals in patching the lunetta is to make interesting beats or sequences that have the ability to morph.  The 4512 does this without needing a ton of switches and diodes to make it work.


The pin layout is very straightforward and easy to implement.  Pins 1 through 7 as well as pin 9 are the channel inputs.  Pins 11,12 and 13 are the controllers that select which of the 8 channels is heard or "on".  Pin 15 when High, disables the ABC controllers.  Pin 10 is Inhibit.  Output is pin 14.

How to interpret this?
  • For the 8 channel inputs: connect any oscillator, gate outputs or divisions from the 4040 to them.  I like to use divisions because they have a decent pitch/octave range.
  • For the ABC controllers, connect 3 oscillators
  • Tie pin 15 to ground.  We want the 3 state selection to work!
  • Inhibit can also go to ground or can be brought out to a jack so you can decide when you wish to inhibit the effect
  • Your output can be used to clock another ic or can be sent to your mixer/amp. 
A simple lunetta using 4 oscillators (40106), the 4040 for divisions and the 4512 to select from those divisions, can make a great first machine.  The ABC controllers play a huge role in the variety of sounds that are available.

  video

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