on a fleamarket.
i won't anger you with the price.
after using it for a while now, i must say i love the sound range this thing has - but it lacks a little in the control department.
i guess my main complaint about this thing is that there's two completely independent voices, with seperate triggers, but they get treated like a single entity. for one, their outputs get summed to a mono signal. so no way of processing the voices separately. that's a bummer.
to further that approach, external pitch control also applies to both voices.
and, to top it all off, the only way to control that pitch externally is through a footpedal or potentiometer. not quite the most accurate way there.
and then i came across this video:
where the thing is modded to track CV! now there's an idea. WANT.
so. the search begins.
only schematic to be found is a crummy, hardly readable piece of bluhh.
might as well just open up the case.
first thing i noticed is that ALL jacks used are stereo. good news, since the schematic shows that both voices get summed all the way at the end, using just two resistors. hooray for soon-to-be split stereo!
now, the tune jack is also a stereo one. the tip sends +9v to your footpedal, the ring returns the diminished voltage.
so if you want to run CV into yours, use an insert / stereo to dual mono cable, and use the end that doesn't have a voltage on it, ok?
upon which you'll probably find much the same as i did - it does repond to external cv, but not quite as one would like. response to both expo and lin seems way out.
turns out it does track quite consistently, but not 1V/oct - more like 0.4V/oct or something.a simple voltage divider network (or an attenuator on yr modular) could do wonders here. drop your voltage a little and you should be good to go.
i decided to do that inside of the SY-1, so it not only becomes compatible with other CVstuff, but i also get to use the stereo jack to control both channels independently. i'm never gonna use the footpedal control anyway, so i can safely lose the 9v connection.
here we go:
ta-daaa. nice dual channel CV controls, trimmable to play in tune over about 3 or 4 octaves.
that's more than most drummers.
one option i looked into was changing the feedback resistor on the opamp mixer, but as you can see that would have affected the response for the front panel tune slider, the S&H, LFO and EG. didn't seem like the way to go. i also tried a simple resistor divider at the front end, but this seemed like the more elegant solution.
(EDIT: SCHEMATIC SIMPLIFIED AND IMPROVED.)
only thing left to do was use the stereo output jack in it's intended form - aka NOT mono -
and now i've got a true dual percussion synth. aces.
and although it looks quite easy on paper, i must say the good folks at Pearl really did build this thing like a tank. build quality second to none, with hardly any room left for mods.
glad i managed the lot without having to drill the case..
