spring reverb for fx unit

[runmikeyrun]

You know we have all spent time knocking on an amp with a spring reverb making wacky Iron Butterfly type sounds.  Instead of bolting a reverb tank to my effects board, is there a way to make a compact unit that i can tap with my foot AND still fit on my pedalboard?  Maybe get an old unit and shorten the springs?  Or will that make the reverb time completely short and useless? 

I have an understanding of how a spring reverb unit works, between springs and transformers, but not much with the actual rest of the circuit.

[Nasse]

Been thinkin if its possible to feed the spring with a suitable signal that sounds in the output like somebody kicked the thing. If some commercial units do have a button for this then it can be done. Perhaps short noise burst can do the trick.

Danelectro Spring King costs about 82 euros + shipping at this side of water. The kick pad may be just mechanical on this...

edit gut shot pic

[petemoore]

  Simply kicking it is the vintage method, any automatic reverb kickers lose the mojo...
  Connect a trashy speakers coil to the suspended spring case. [you'll probably need a big driver], use your funky amp to drive the kicker. Maybe some other type of motor...kicking many ways first to find the best angle for shakey spring sound.

[Barcode80]

solenoid driven by 12v line, with small hammer attached, mounted in the amp head where the swing radious of the hammer will make contact with the tank when struck. set up a momentary footswitch to trigger the solenoid.

[runmikeyrun]

I don't think what i meant came across properly.  I have no problem kicking a reverb tank, i just wanted to know if i could make a small spring reverb to put in a stompbox (albeit a fairly large one).  If i could fit a spring reverb into a stompbox i don't mind standing there and tapping on it with my foot, i just don't want to bolt a whole tank to my pedalboard!

[Mark Hammer]

"Good" reverb has little resonance, which implies lots of reflections, and a more diffuse sound.  Shorter springs tend to be stiffer (greater damping = less decay time) and more resonant, which yields lesser-quality reverb sound.  You also tend not to find short units with more than two springs (although the Danelectro picture gives lie to that generalization).

I've had a DIY reverb project on my bench gathering dust for two years now that showed some initial promise.  Many large hardware stores will have a section with springs and fasteners.  I've found some nice little springs at Home Depot and Canadian Tire for just over a buck apiece.  When stretched such that they are not too tight and not too saggy, they're around 8-9" long.  I soldered one end onto the middle of a piezo disc and glued (with epoxy and/or cyanoacrylate) the other end onto the dome of a speaker voice coil on a small (2") speaker.  The speaker is driven by a fairly normal 386-based practice-amp circuit, and the piezo side simply feeds the same sort of high-impedance preamp you'd use with a piezo pickup.  Set the gain and tension just right, and you can get some acceptable reverb sound within a relatively compact space.

One of the things I want to tinker with is using a Y configuration, whereby 3 springs are linked together via a solder joint such that one driver spring wiggles two receiving springs, each feeding their own piezo disc.  The second set of springs is unlikely to exhibit the identical wiggle properties as each other, getting a more diffuse sound.  If you want to guarantee it, you simply either clip a few turns off one of the springs, or position their piezo discs such that one spring is just a little more slack than the other.

In principle, one should be able to produce a floor-type spring reverb pedal similar in size to the Danelectro one.  Imagine the receiving/sensing end of the springs is spread out in a Y shape to the corners of the chassis, and you can actually end up with a longer spring distance (longer decay time) than the Danelectro can produce.

[StephenGiles]

Mmmmmm, "Many large hardware stores " - you're lucky to find one in an English town, they have died a death here!

[m_charles]

Danelectro Spring King costs about 82 euros + shipping at this side of water. The kick pad may be just mechanical on this...

Just FYI, The Dano is a digital pedal. It does have springs for the "crash" pad, but the verb itself is 100% digital.

good luck!

chuck

[Mark Hammer]

Really?

What's the primary chip in use?

[jrc4558]

Solenoid. Best and simplest way.

[m_charles]

unsure about the chip mark. I was gonna buy one a while back, I thought it would be a poor man's Little Lanai spring verb. I did the usual investigating and found out that Dano marketed it in a way that it seemed like an analog pedal, but they never actually say it is (a bit shady). Apparently the proof for many who couldn't tell a digital chip from an analog one, is that if you remove the springs, the verb works fine, the "crash" thing just doesn't work.

chuck

[ambulancevoice]

[Meanderthal]

 LOL! I have a couple old spring tanks layin around for years, yet I never thought of that!  Phono preamp? Yeah, that makes sense!

[runmikeyrun]

Thanks Mark, that sounds like an interesting build, i am pretty sure i have a small speaker around here... RS should have some piezos for not too much money.  I'll add it to my list of things to build (which i am suprisingly keeping up on) since i got a hand me down palm pilot.  Everyday my tasks lay out what i need to mod, built, or repair. 

I get a decent amount of stuff from home stores to build pedals... i built the Weapon of Mass Distortion (opamp muff fuzz) into some 3" pipe with holes drilled in the end caps for the jacks.  Well it certainly looked like something that Homeland Security should have sent me to Gitmo for life over, and the dang thing got stolen in NYC two days after the london subway bombings a few years ago... with my fingerprints all over it... haha  probably sitting on the bottom of the East River but i expected to see it on the news one day when someone found it on a street or in a garbage can.  Thief probably freaked out when he got it!  It looked like a stompbox to me but... well... a lot like a b omb to anyone else with knobs and switches on the outside.

Alex, that's a great idea but sadly i do not have a phono mixer nor an old tank.  But if i did... hmm... fantastic idea!