[sdiy] Muse musings

[Gene Stopp]

Question for Muse builders - did you make the major scale converter thingey
also? If so, how did you do it? It's just another block in the block diagram
in Hal's book.

Been musing on this lately - I can think of a few ways to do it, seems like
a fun topic...

By "major scale converter" I mean a digital word-in word-out circuit which
takes a binary count on the input side and produces a parallel output which
is the binary numbers for a major scale if put into a linear DAC with 1/12
volt output steps. Example:

Input   Output
0000    00000    C
0001    00010    D
0010    00100    E
0011    00101    F
0100    00111    G
0101    01001    A
0110    01011    B
0111    01101    C
1000    01110    D
1001    10000    E
1010    10001    F
1011    10011    G
1100    10101    A
1101    10111    B
1110    11000    C
1111    11010    D

etc.

One way to do this - look up table. Another way - diode matrix. Both seem
pretty easy, except the lookup table may require an EPROM or similar thing.
An advantage to the EPROM approach is that it would be easy to make
alternate "pages" for different scale types (major, minor, etc.).

The diode matrix is very simple for a small number of bits (i.e. just a
couple of octaves) but you could have a few bits for note select and then a
couple more bits for octave select.

- Gene


-----Original Message-----
From: Gavin and Delia [mailto:elmystico at earthlink.net]
Sent: Wednesday, July 02, 2003 3:40 PM
To: Tim Ressel; Synth-Diy
Subject: Re: [sdiy] Muse musings


where is the original schematics for this project?
----------
>From: Tim Ressel <madhun2001 at yahoo.com>
>To: Synth-Diy <synth-diy at dropmix.xs4all.nl>
>Subject: [sdiy] Muse musings
>Date: Wed, Jul 2, 2003, 4:11 PM
>

>Hey gang,
>
>A while ago I built the Muse out of the Chamberlin
>book. It is a sequence generator consisting of a
>divider chain and shift register driven off of a
>variable clock. the input of the shift register has a
>parity tree on it, the inputs of which can be
>connected to any og the shifter of counter outputs. My
>version so far has only an 8-bit DAC for an output.
>The DAC inputs can connect to any of the outputs.
>
>I've been looking to expand it, and I think I know
>how: The good ol' DG408. 8-to-1 mux with TTL inputs. A
>few of those along with a set of jacks with note
>voltages on them will make a nifty little bugger.
>It'll do sequences or random notes from a list you
>choose. 
>
>Groovy, eh?
>
>--tr
>
>
>
>
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