multiple-type Digisound VCDO thing?

[Ken Stone]

>2 points:
>
>1) With the adjustment of one resistor value, the VCO in the ASM-1 would 
>be perfect for tracking at the high frequencies required in the VCDO.  
>And the parts count wouldn't go up that much.  Yeah, I know Paul has new 
>3340's coming soon, BUT, until they're available, I'm kinda nervous about 
>using them.

Agreed. I'm not that fond of non-discrete designs.

>2) Why settle for a 2732?  I'd go for a 512kb or 1Mb part - from most 
>places they're actually cheaper than the 32kb part (which is way, way 
>past its heyday).

I know the 2732 is from the dark ages, but until we get some enthusiastic
fellow creating lots of wave tables, it's twice as big as what we need.
In this case, as I'm doing this board primarily for myself, I didn't see
much point in using a bigger part i would need to pay for instead of one
of the dozens of devices I have to hand. The design has provision for
two more bits in the table selection, bringing it up to 128k if need be.
further than that and separate chips (like in the original) would be needed
for the table selectors where I am using one chip. 

The next problem with so many waves in a single device is addressing them 
all. Digital addressing would be the best for choosing a particular sound,
but incremental addressing ala VCDO is easier to build/interface. Does one 
go to a "3d" array of sounds instead of the straight "2d" (1 group of banks)
approach of the Digisound.

Sometimes the all singing all dancing solution is just too cumbersome.

BTW, at the moment there is no display circuitry on my board. That will be a
second sub module.

Do musicians use banks "0 to 7" or would they prefer banks "1 to 8"??? :)

Ken

_____________________________________________________________

                Ken Stone  sasami at blaze.net.au
                   ** Catgirl Paradise **
               <http://www.anime.net/~kens/>
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             <http://www.blaze.net.au/~sasami/>
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