[sdiy] Thinking out loud....

[bayne d'artagnan]

It's a waste of 3394s which are worth as much as 80017As and the CEM
is not a very good sounding part to begin with. The idea itself,
however, is  a good one and it's not very difficult. An excellent
choice would be to use 2044s with a separate VCA. You can probably get
a great sounding synth for little money, but  a bit of effort, by
building a daughter board that held a 2044 and a 6110 VCA. Both can be
had cheaply.

The 2044 will give the synth a different, slightly less plastic,
character whereas the VCA will preserve some of the Roland-ness
without the expense of the BA-662.

If you really want the CEM sound then the best part to use is probably
the 3372 which also has VCF/VCA on a chip and no VCO to get in the
way.

If you want a more vintage Roland sound you could go for a diode
ladder filter out of discrete parts and a pair of 3080 VCAs, one for
the output, one for the VC resonance. This will probably be a slightly
taller daughterboard, but it should fit.

You could make the 3394 work, but it's wasting the VCO and there
aren't very many chip-vco choices available to use for such projects.
You could sell two of them and have enough to buy six times (2044
+BA6110) and still have cash left over.

On 11/10/07, Travis Shire <tshire at charter.net> wrote:
> I have this Juno 106 with the filter/vca chips dropping like flies. I've
> already replaced 2 and refuse to stick more cash into this thing. Now I have
> some CEM3394s around that I was saving for a project that I never got to.
> How feasable would it be to cobble in the CEMs disabling the osc and going
> in through the EXT input for access to the filter/vca? I don't remember
> poking around for min/max ctrl voltages in the Juno so for now its just a
> thought......and then theres the 6.5v rail to deal with as well.
>
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