Spring reverb pedal idea

[Mick Bailey]

Here's a thought, and everyone will post to say "there are hundreds of these out there made by..." but here goes anyhow;

Back in the late 70's I took apart some delay lines out of an old computer (a Mu-Set). They consisted of a spring coil like a large clock spring with a driver transducer at one end and a pickup in the centre. Spring was lightly held in place by some very fine rubber mounts. I've recently been thinking of these and the suggestion here is the possibility of a DIY reverb pedal build in a smallish box using a thin clock spring or similar and a transducer arrangement. Could make a fairly compact pedal to fit in a Hammond box, though I don't know what the delay time would be like or what it might sound like. A simple driver/recovery circuit using a couple of op-amps should suffice, possibly just using a standard spring line circuit. Investigations into suitable transducers would need to be undertaken, but it may be worthy of experiment and should be fairly easy to set up on a piece of MDF or timber.

Any comments?

[KazooMan]

I don't see why it wouldn't work since you can make mechanical reverbs in a variety of ways from the traditional springs to huge plate reverbs.  A couple of issues do come to mind.  One is figuring out a good way to mount the spring so it is free to vibrate.  Another would be what delay time you could achieve (you mentioned this).  I think it wouldn't approach the linear spring units.  Also, those reverbs use multiple springs of different length and number of turns to achieve a good effect. 

Having said that, you can make a spring reverb from some pretty common, cheap materials, just not as compact as the one you envision.

Here's a link to someone who made a unit out of a Slinky toy.

http://www.electronicpeasant.com/projects/springs/springs.html

[Mark Hammer]

Actually, that's an interesting idea.  Key to this, of course, would be that the coiled portion of the spring steel would be suspended in some manner such that it could vibrate freely.  But yeah, there is no reason why the transmitting medium HAS to be coiled in a traditional spring fashion.  All it has to be able to do is vibrate after being briefly energized, and be capable of transmitting that energy from one end to the other.

[petemoore]

  I'd put the pickup on a slide/adjust for up and down the spring placements.
 Guitar pickup for output source ? sounds interesting...
 And I'd guess it'd be good output considering the spring density, probably similar to a guitar string.
 I wonder if the 'focus' of the field would matter, the string being a solid mass of 'thin' line for taking a reading to convert to electron flows, the spring being wider and hollow if ferrous, the magnet will sense it's motion when in close proximity.

[Strategy]

I once heard of a synth-DIY project being developed that uses a slinky!! 

[yodude]

Cool idea.  Linear spring reverb units use linear transducers, so wouldn't a coil spring unit need rotational transducers?  If so, I guess you could make one out of a linear transducer plus a gear ...