Questions from a novice regarding MIDI, CV, Gate, and EFM...

[CasioRZ1 at aol.com]

Hi All,

I'm new at the whole synth DIY thing, so please bear with me if any of my 
questions /concepts/terminology seem particularly silly or if this post 
rambles a bit.  I really would appreciate your feedback! 

I have constructed a pretty cool keyboard style controller based on the paia 
touchswitch diagram at <a href="http://www.paia.com/touchsw.htm"> paia's 
touchswitch stuff</a>.  The touchswitches take the places of keys, 
controlling 48 SPST relays along a resistor bridge type thing w/3.9 volts 
across it (idea taken from the EFM site).  

Right now, my setup (I'm guessing) will only supply CV, right?  I guess I 
need to be able to generate "gate"  too, but I really don't know what gate 
is... my understanding is that it is a +voltage pulse generated w/each 
keypress to start an envelope?  If so, is the length of the pulse generated 
supposed to be independent of the time that the finger is held on the key?  

Next group of questions:  Since none my synths have CV in, I lack a VCO to 
test my touchswitch controller with.  SO, I went down to local parts store 
and bought/built an "op amp function generator kit", a tiny (3 by 3 inch, 
maybe) project.  It actually sounds pretty cool (really!), and I can kinda 
control it w/my touchswitch setup... but 1.  it is really, really unstable 
(tuning drifts) and 2.  its frequency is controlled exponentially whereas my 
touchswitch controller (as I understand it) is linear.  Is there a schem 
somewhere for converting the latter to the former?   And, in regard to the 
pitch drift, is there anything I could do to stabilize it?   The circuit has 
very few components(<15), the only IC being an LM348. I have changed out all 
the resistors to 1% tolerance which didn't really help, and, the only other 
components are 2 ceramic caps and 4 diodes.... I realize that it is probably 
difficult to diagnose w/o seeing the circuit, but is the LM348 the likely 
problem?  I have ordered another VCO kit (linear and intended for synths) but 
am still curious as to why the ptich of the function generator drifts, if it 
is correctible, and how to convert linear CV to exponential.

Almost the last question:  On the Electronics for Musicians (EFM) site, there 
are a bunch of projects that appear to be for sale... I would like to 
purchase one of them, but can't seem to find the e-mail addy for the guy who 
designed the projects, a certain "tom g".  Anyone know how to get in contact 
w/him?

The last question:  (looking ahead):  How does one convert CV to MIDI?  I've 
seen lots of MIDI->CV schems/products, but I haven't seen anything that goes 
the other way.  Once I've finished my controller/synth project, I would like 
to be able so send MIDI (even just note on/off) with it if possible... could 
someone point me in the right direction?

Thanks for reading this, and for any info you'd be so kind to send!

Derek
casiorz1 at aol.com