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Synching a Vortex?
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
...found a Vortex list? :-)
>Date: Thu, 30 Jan 97 18:06:48 -0500
>From: "Arnim X. Sauerbier" <firstname.lastname@example.org>
>To: email@example.com (DIY)
>Cc: firstname.lastname@example.org (Andrew Lunstad),
> email@example.com (Chris Sattinger), firstname.lastname@example.org
>Subject: Synching a Vortex?
>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.
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
>Encoding: 59 Text
>Subject: Re: Synching a Vortex?
> 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
> 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
> 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
Then Saul Stokes <email@example.com>
>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?