DIY Reverb...now with more Slinky

[iaresee]

This is cool. Damn cool. A home made reverb tank using Slinky coils. It's MONSTEROUS! And for damping: cucumber slices. Why not?

http://blog.makezine.com/archive/2008/11/springatron_3000_awesome.html?CMP=OTC-0D6B48984890

[petemoore]

  Outstanding ! 1
  Also the string vibrator/reverb thing is profound !
  Interesting use of coils as pickups and drivers, clustered around harmonically resonant 'items'...too cool !
 

[Joe Hart]

The other stuff on the that guy's site is wild!
-Joe Hart

[Mark Hammer]

Ian,

Make a note to pester me to finally get around to completing my "more"-DIY spring reverb.  I started it a couple of summers back, using some nice springs I got from Home Depot or Rona for around a buck a piece.  The springs are being configured in a Y pattern.  A small speaker, with most of the cone "surgically removed" to reduce audible sound produced by the speaker, drives the main spring.  The spring is attached to it via a dab of epoxy in the centre of the voice-coil dome (if a 2" speaker can be said to have a dome).  That single spring is soldered to a pair of secondary springs in a Y-pattern, and the secondary springs are soldered to the piezo element in a pair of crystal mic cartridges.  The whole thing can be built in a fairly small enclosure.  By my reckoning, about 4" x 10" by 2" high, enough to sit comfortably inside of a small portable battery-operated amp.  The driver spring is powered by a 386, and the recovery springs are fed to high input-impedance op-amps.  The mic cartridges are quite sensitive, generating 50mv easily, which doesn't require a whole lot of recovery gain to produce a decent amount of reverb to blend in.  I bought a fistful at Computer Recyclers here in town when they actually sold stuff.  I believe they were from old-style telephone receivers.  I imagine it might be possible to replace them with more conventional (and easily located) large piezo disc.  The nice thing about the mic cartridges I bought was that the sensor inside is housed in a manner that doesn't damp them in any way.  I imagine if you had a piezo disc soldered to the end of the spring, you'd have the challenge of securing them so they don't flop around but don't sit rigid....or maybe rigid is what you want, but finding a way to hold a round disc in place requires some ingenuity. whether it is held rigidly or softly

I've done some trial runs with a prototype, and the reverb sound was passable.  Not a long accutronics 6-spring, but passable.  What I need to do is: a) whip up a board with the finalized electronics, b) machine the final enclosure, and c) take pictures of every step of the process.

If it "works" the idea of $10 DIY spring reverb becomes a reality.  I just hope I can finish before the springs get rusty.  BTW, the Y pattern is to produce more variability in arrival times in a smaller space.  Apparently Sanyo used something like this years ago.

[iaresee]

Duly noted. Sounds pretty cool. And who doesn't want to build their own reverb? Total control over the ambiance of your sound...enticing.

Actually, I have something for you. We had a little accident here at work and we've got some dev kits that can't be given out now. Cosmetic damage. One with your name on it if you want it.

[sean k]

Yeah, the guys site is great but I was looking for more detail of the type that would interest people like us. Then again the shear fact that hes made what hes made and the aesthetic hes into makes for quite the motherload of inspiration. I especially enjoyed the guitary thing where the two speakers at the neck, obviously in reverse phase to each other, play the guitar strings and then have those coils sitting over the strings further down the neck, which I suppose have the same signal fed into them as the speakers, which excite the strings further.
Is that what would be happening?

I'm thinking those coils, thats the part that really interests me, would be wound around bright steel, as opposed to a permanent magnet, and the combined impedance be such that 6 would equal 8 or 16 ohms. Working out how many turns of a specific gauge... thats where I'm completely out of my league.

[frequencycentral]

I'm thinking those coils, thats the part that really interests me, would be wound around bright steel, as opposed to a permanent magnet, and the combined impedance be such that 6 would equal 8 or 16 ohms. Working out how many turns of a specific gauge... thats where I'm completely out of my league.

I thought that guy would be right up your street Sean! When I saw those coils I first thought they were Fender Rhodes pickups - they look pretty similar. You might be able to use them at a push. They are easily available on Ebay - I had to replace seven pickups in a Rhodes I bought to sell on. Even with shipping from the USA they were cheap enough.

[sean k]

Well you could do me a favour by measuring the actual resistance of you Rhodes coils and the inductance if you have that on your multimeter though I'd suppose that they'd, the Rhodes coils, would be permanant magnets alike guitar pickups and in this instance, I'm guessing of course, that a magnet would be detrimental on a string at mid length whereas a bright steel would be inert, or unaligned, until a current was active in the coil... like a solenoid.

Anyways, I picked up a whole box of early seventies electronics mags from the side of the road and was quite taken aback at how much audio type projects were published in those early days of silicon. Heres one to make thats simple and straight forward.

I'd actually been in contact years ago with Paul Crowther, peachs and cream guy from early split enz, and he advised using a 2N3819 fet for something I was doing and these early projects are full of 2N3819's so it's interesting how usage of specific discretes is linked to their usage in times past...

It's a biggish file so I'll just throw in the link.
http://i4.photobucket.com/albums/y115/quickkiwi/effects/simplesynth.gif

[frequencycentral]

Hmmm - I'm measuring 200 ohms across a single Rhodes pickup from my spares box. I think there is some weird series/parallel arrangement within the Rhodes itself if I remember rightly.

[Paul Marossy]

Wow, that is pretty wild. Is there any soundclips of this thing in action?

You should also check out "The Beast"! Look at the wires in this thing. 

[Zben3129]

Wow, that is pretty wild. Is there any soundclips of this thing in action?

You should also check out "The Beast"! Look at the wires in this thing. 

Lead dress 101 

[petemoore]

  mmmm multi-color Spaghetti !.
 

[sean k]

I got a fatman from Paia that I half finished a few years ago and when I was doing it I added a whole bunch of extras and mods and I think I quit it because it was going to look like that, well sort of like that. When I go back in and get going on it again I wanna do a colour code thing and make sure I route bunchs of wires so that exact debugging nightmare won't come into existence.

That guy is just incredible...Amazing for someone who professes to not actually know that much about electronics.