[sdiy] Since it's 9/09, it's time for more 909 questions :)

[Rob B]

not bored at all!

;)


aim : cybrgzr0 <--last thing is a number
----- Original Message -----
From: Colin Fraser <colinf at ntlworld.com>
To: 'TooManySynths' <p8051 at yahoo.com>; <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, September 09, 2001 4:48 PM
Subject: RE: [sdiy] Since it's 9/09, it's time for more 909 questions :)


> > -----Original Message-----
> > From: TooManySynths [mailto:p8051 at yahoo.com]
> > Sent: 09 September 2001 21:44
> > To: Colin Fraser; 'TooManySynths'; synth-diy at dropmix.xs4all.nl
> > Subject: RE: [sdiy] Since it's 9/09, it's time for more 909
> > questions :)
> >
> >
> > One more question:
> >
> > I assume the accent pulse is a positive going pulse.
> > But, does the attack accent get triggered off of the
> > negative edge?  I ask this because the pulse is fed
> > into the cathode of D5.
>
> No.
> The trigger pulse switches on Q1, Q1 conducts and pulls down the base of
Q5
> lower than it's emitter via D5 and R34. This switches Q5 on and allows the
> accent cv to charge C12 for env2. This happens at the leading edge of the
> trigger pulse.
> The trigger pulse is inverted at the output of Q1. The inverted pulse is
> inverted again by Q2 which charges C7 via D6.
> The triggers at D5 and D6 are opposite senses. The non-inverted trigger at
> D6 is inverted again by Q3 before it reaches the base of Q4 - which then
> works in the same way as Q5 (with the difference that C7 and Q3 stretch
the
> pulse length, and give it a slight downward slope).
> It takes a negative pulse relative to the emitters to switch on Q4 and Q5
> (PNP).
>
> Colin f
>
> (Hope nobody's getting too bored with this yet...)
>
>