Ever since I completed Rytm1, one of the most interesting bits left over from the electric organ (and just waiting to be built into something usable) was it’s spring reverb tank. Being a sucker for dub and reggae, I knew I could sure appreciate having a hardware spring reverb unit to play around with. In that sense, this was of course a obvious project.
When stripping the organ for parts back in 2006, silly and hasty as I was, I removed the tank without looking at it’s driver electronics at all. Had I been more clever, I would’ve also stripped the driver stages with the tank. Or at least reverse-engineered the circuit… but no..
The thing with these spring tanks and their driver electronics is that, assuming you want to do it properly, the driver stage should match the impedance of the tank’s transducer. Whereas a modern spring tank comes with clear specs (and/or markings) of the transducer impedances, mine being stripped from some long-forgotten organ brand the tank had no other markings than ‘INPUT’. Lucky me they got at least that spelled out on the case.
Anyway, left with the plain spring tank I experimented with some driver electronics schematics on a couple of occasions. Unfortunately those sessions never got further than disfunctional (or even overheating/smoking) collections of parts and my dream of a hardware spring tank realizing into something more concrete was delayed to a later date.. all the way up until now!
Chatting briefly about my driver electronics issues with some folks on IRC recently, I eventually presented my case to Michael Kingston (developer of the excellent RetroBand VST). Based on his own experiences he suggested simply driving the tank directly from the effect sends of a mixing console.
D’oh! Now why the fuck didn’t I figure this one myself?
As it’s highly unlikely I will be plugging the tank directly into any instrument, there’s really no need to do impedance matching. Whatever input level the tank might need, the fx send stage of any mixing console can handle, no doubt.
Besides giving the tank a enclosure, I figured I’ll make the unit a few notches more “recycleish” and toss in the amplifier board from a set of old Labtec multimedia speakers. This amplifier board will work as a input/output impedance matching stage (albeit a crude one), if such is needed. Figured if I connect it to the tank through switched jacks, I can use the tank with or without amplication. Just to test the combination, I hooked the tank and the amplifier up with my mp3 player..:
..and nicely it does play indeed! Yay \:D/ .. Tinker away, build posts to follow.
Oh and the topic for this post? That’s the name I chose for this spring reverb unit ;)