[sdiy] Re: SDIY Withdrawal Symptoms

[Neil Johnson]

Hi,

>> BTW one list member was making a series of small
>> modules... His first was a very small ASM style
>> VCO.  Who done it ???  (confess !)

Ummm ....  <raises hand> .... me....

Things (PhD, marriage, buying a house) seem to have got in the way of 
progress...

> I personally think a common pin out isn't essential, it woudl be hard 
> to do this for a quad VCA, a VCO and a VCF.

True.

That reminds me, I should start attacking those modules once more.  The 
3-pole VCF is the first to get attention (I'm not yet happy with the 
VCO).

> I would suggest a common number of pins, say 16, with common spacing, 
> again 0.1"seems sensible, and with common supply rails +15, -15, +5 
> and GND. So the supply pins are always on the same 4 pins, this would 
> avoid connecting stuff upwrong and blowing modules.

Yes, that's the idea.  On the signal side, its far more difficult, 
other than to have a defined electrical interface that is robust, 
allowing any input to drive any output.  That, and making all modules 
fully CV-ed, which is fun in its own way.

> I would also like to suggest a common form factor, SIP (a bit like a 
> SIMM). It Seems, to me, the most sensible as you can make the SIPs 
> taller and double sided if you need to fit more on, without taking 
> more board real-estate.

SIPs are fine up to a point... Without mechanical support the connector 
pins are under a lot of stress.  Guide rails (like in rack mount) might 
be a way to go, but then if I was going to do that I'd go the way of 
standardising on Eurocard 100mm x 150mm PCBs, and either DIN41612 or 
DIN41617 connectors for the backplane, carrying power and prepatched 
signals.  Everything else would be brought out to the front panel.

Cheers,
Neil

--
Neil Johnson <http://www.njohnson.co.uk>