4522 melody generator

[jcintheus]

Idea from a circuit in the CMOS Cookbook page 311. Take 2 4522 down counters, feed the jam inputs with a 4015 dual shift register. It's basically a divide by 100 counter cycling through it's divisions.
http://soundcloud.com/bill-chavez/super-melody-generator

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[jcintheus]

Here's a slightly better description: Instead of the thumbwheel switches I used a 4015, one clock at f, and the other at f/4, to control the inputs. The output is a very narrow pulse so, to fatten up the sound, I fed it through a JK flip-flop set up as a divide by 2, for more of a 50/50 duty cycle. The data ins on the 4015 are fed from an xor ladder (4070).

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[tjookum]

Thanks for doing the research, it sounds great.

I believe I saw somewhere that stanley lunetta himself used these kind of very long unpredictable sequences in his first machines. In theory this could run forever right?

[loss1234]

are you R2R ing the outs in your audio clip?

its funny, i have looked at this circuit in CMOS cookbook many times and for some reason, never thought about driving it this way!

great job

[loss1234]

also...you said

"The data ins on the 4015 are fed from an xor ladder (4070)."

could you let us know what is feeding into the xors?

i understand the what clocks to give the 4015s but not the data

thanks!

[jcintheus]

You don't need an R/2R. The counters divide the input by 0-99, The output is the "fout" from the schematic going into a JK flip flop(divide by 2). The XOR is fed by a couple of 40106 oscs. The data is the stream of bits that gets shifted down the register. It doesn't really matter what the data is, as long as it's not identical to the clock.

[jcintheus]

I'm not using the BCD down outputs at all, just "f out".

[loss1234]

Thanks!
I cant believe i overlooked the F out
!

[loss1234]

i tried setting this up last night. WOW

I followed the CMOS cookbook diagram and then

a 40106 clock into input A of an XOR
a 40106 clock into input B of an XOR

The output of this into the Data in A of the 4015

then another 2 40106 clocks into the DATA b of the 4015

then 2 more clocks into the clocks of the 4015

and then it did not seem to work right.

I then realized I needed another 40106 for the clock to the 4022!
i put the out through a divider and VOILA

one of the most interesting noisemakers I have come across!!


thanks!