Quantizer questions

[Christopher List]

Hi DIYers - 

I want to build a quantizer for my sequencer. I really liked the idea of; 

clocked counter->D/A->multiple comparators->multiple S&H's

I especially like the fact that you can switch bits in or out to get whole-step 
intervals and stuff...

I was thinking of going with the AD7245A for my D/A converter and using the top 
8 bits. I like the fact that it'll run off of +/-15v and has an output in the 
+/-5v range. Before I go dropping $16.75 on one chip, I was wondering if I've 
made a good choice :). I figure the more bits in the A/D converter, the better 
resolution I'll get by using a smaller ratio of "significant" bits to 
insignificant - is this an accurate assumption?

I was also wondering what others have done in terms of range. Have you 
quantized over the whole -15v to +15v range (360 steps) or just -5 to +5 (120 
steps) (which is the maximum output of my sequencer). I think -10 to +10 would 
be a good compromise...

Is the 4060B set up as an oscillator/counter reliable? What sort of frequency 
should I go for (I know this depends on the number of steps) - I was thinking 
around 1kHz per cycle, or 240kHz for 240 steps...

Thanks for any input,
Chris