Synching a Vortex?

[matthias@bahianet.com.br (Matthias Grob)]

 I forwarded a message of this kind before.

Should we invite them to transfer this discussion to the loop list or
transfer ours about Vortex to Synth-diy (where there are more solder iron
interested) or
...found a Vortex list? :-)



>Date: Thu, 30 Jan 97 18:06:48 -0500
>From: "Arnim X. Sauerbier" <arnims@usa.globelle.com>
>Organization: Globelle
>To: synth-diy@horus.sara.nl (DIY)
>Cc: ajl@bitstream.net (Andrew Lunstad),
>        satti002@maroon.tc.umn.edu (Chris Sattinger), redbooklab@aol.com
>Subject: Synching a Vortex?
>Sender: owner-synth-diy@horus.sara.nl
>Precedence: bulk
>
>Hi folks!
>
>Not a synth question, but a musical DIY topic nonetheless:
>
>I've got a Lexicon Vortex (worth the $149 sale price IMHO).  It lets the
>user set delay times by tapping a 'delay/tap' button twice.  The box has
>no MIDI interface, but I'd like to sync the delays to my MIDI sequences!
>
>I was thinking of the following hack:  use one of the outputs of my drum
>machine as a click, then build some kind of circuit that closes the
>contact of the 'tap' switch whenever a voltage peak (from the drum
>machine) is detected.
>
>What would such a circuit look-like?  Perhaps a transistor that triggers
>a relay that closes the 'tap' button?
>
>What would you do?  Any other solutions that wouldn't involve using-up an
>output on my Drumstation?
>
>Thanks!  Sorry for my glaring ignorance.
>------------------------
>Arnim


Then the answer of Gene Stopp who is an experienced synth inventor. His
posts are nice, clear and fundamented:

>Date: Thu, 30 Jan 97 17:00:36 PST
>From: gstopp@fibermux.com
>Encoding: 59 Text
>To: synth-diy@horus.sara.nl
>Subject: Re: Synching a Vortex?
>Sender: owner-synth-diy@horus.sara.nl
>Precedence: bulk
>
>     I think you are on the right track...
>
>     It is distinctly possible that the Vortex tap footswitch input is
>     looking for a short to ground as the trigger event, in which case you
>     could skip the relay idea and just use the transistor to ground the
>     input (like a Moog S-trigger). To turn on the transistor you could 
>use
>     a voltage trigger from a MIDI clock-to-voltage pulse converter, or
>     like you say derive a pulse from an audio event such as a drum hit.
>
>     Converting the audio pulse to a voltage trigger can be done with an
>     envelope follower plus a comparator. Actually for such a specific
>     application you can probably throw together a simple
>     diode/cap/resistor peak detector into an op-amp into the transistor
>     and be done with it. Probably you'll need a 10x preamp on the front
>     end. It might have to be tweaked to the specific drum sound that you
>     use, but since the Vortex is expecting a "sloppy" pulse like a human
>     foot on a switch, it probably doesn't care too much about pulse
>     duration.
>
>     The way I'd figure this out is with a protoboard, an assortment of
>     components, and a scope. Hey I have a Vortex now, maybe I'll check
>     this out some time (next week at the soonest...).
>
>     A couple weeks ago I built a MIDI-clock to voltage pulse divider
>     circuit on a single chip, but that's another story...
>
>     - Gene
>     gstopp@fibermux.com

Then Saul Stokes <n9540283@gonzo.cc.wwu.edu>

>Hi Gene, I thought I would let you know that I would also be interested
>in a circuit like this if you decided to think one up.  There's probably
>quite a few people actually.

...and another few on this list?

Matthias