[sdiy] TRYING TO RECREATE/CONFIGURE THE psych tone for modern use.

[Dan Snazelle]

THE PSYCH TONE....

a psuedo random tone gen capable of 1728 different sequences.
I have really wanted to build this or something like it for a long time. at least the tone computer part and the pause gate.




to start with, here is a link to the original schematics:

http://www.swtpc.com/mholley/PopularElectronics/Feb1971/PE_Feb1971.htm


you can also find an updated version in the TTL cookbook under: A MUSIC COMPOSER (pages 282-284 in my edition)

in the new version he replaces the old flip flops with: 7474's (three of em) they are set/reset types and i am wondering if i can replace them with 4013's?? or maybe even 4015's???

he also uses an 8 input Nand Gate called a 7430
and a 1 of 8 decoder called a 7442
and a 7486

and a 555 clock (easy)


and some rotary switches.

I think if i could figure out how to replace those old fashioned flip flops, i could get the sequence gen and the pause selector working. But then there is the question of how to HOOK up the result of the 1 of 8 decoder to a tone generator. in the old version, he uses a complicated series of transistors (including UJT's) to create a sound based on 3 inputs being high or low.


in the new one, the 7442 has 8 outputs which are to a "note generator" and it says LOW=note
but i dont know how i could implement that with either CV (could i use an 8 step R2r? but that would only get me 8 different notes..right?) or somehow into a cmos based oscillator...



getting sound out of it is a major point of confusion for me. probrably since the old design is, well, so old!

i have heard very mixed things about this but remember, i love all the stuff being built on the LUNETTA thread (on electro-music.com) so this would probrably be great as a CV generator front end.


any and all help appreciated.

really trying mainly to figure out what kinds of flip flops to use and then how to convert the bits and pauses into sound or CV.

thanks so much
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