Converting a spring reverb from junk amp into a pedal

[Heemis]

Hey all.  I know there have been lots of threads about spring reverb pedals, but typically we're talking about a pedal which is driving a larger reverb tank.  I just cracked open a little yamaha practice amp a friend gave me, and found this little spring reverb:




I'll probably use one of the reverb driver circuits out there to push it... thing I'm excited about is that it will fit in a BB enclosure!  Anyone else ever seen one of these little guys or boxed one up in a stompbox?

PS  I am not too worried about the poor sound quality... I got the amp to work long enough to get an idea of what it sounds like, and I like it!

[kevilay]

ive seen a few circuits for this, Ill try to dig one up for you. One thing to remember is when u step on the pedal its gonna bang like crazy from the spring moving. When you get clips I want to hear them

[Heemis]

Haha... I hadn't even thought of that, but I am actually into the idea.  Let's add that one to the "features" list.

[garcho]

Ever listen to King Tubby? Time for a thunder box.
I'm interested in what you come up with; I have a spare spring reverb laying around, too. One of many projects on the list that I haven't even started yet...

[thedefog]

You definitely want to isolate the spring reverb from the actual stomp switch, preferably somewhere that is rattle/shake proof. And as for powering that spring, you'll need a bit more power going to it than a 9v power supply most likely to drive it up to the level to where it will actually sound right, since it is running through that little transformer. And it'll probably need to be build with a bipolar power supply with voltage regulation and decent filtering. Check out this schematic: http://experimentalistsanonymous.com/diy/Schematics/Reverb/Reverb%20Driver%20and%20Receiver.gif

[Jorge_S]

ive seen a few circuits for this, Ill try to dig one up for you. One thing to remember is when u step on the pedal its gonna bang like crazy from the spring moving. When you get clips I want to hear them

It could be split in two boxes, one with the springs the other with the circuit and 3pdt. Other option would be to isolate the reverb with some springs (or maybe rubbers, like they use with some "floating" mics) system.

I once opened an old mp3 player with a micro HD in it, it was mounted with a spring system - hard drives performance is much sensitive to vibration than people would think.

[PRR]

Awww.... how cute!

Decode as much of the original Yamaha circuit as you can. Not much to it, and it is VERY likely that Yama knew what they were doing and EQ-ed the send/recovery amps to make the most of the undersized spring.

You may be able to figure power, in, out, then saw that whole corner of the board off, re-power it in a new case.

Put long leads on the spring, play "catch" with it.... the thunder will blow your audience's minds and ALL your woofers.

[edvard]

I've got a Hammond spring tank that's about that big.
No idea where it came from... bought it for two dollars from a junk store.
I'd be interested in a circuit as well.

[Mark Hammer]

Believe it or not, really cool car radios used to come with those in the late 50's and 60's.  http://www.swtpc.com/mholley/PopularElectronics/Feb1966/PE_Feb1966.htm

One of the things you might want to think through (although Yamaha might have done this for you already) is the different sort of resonance that short springs have, compared to longer ones.  It might be a good idea to incorporate some sort of tunable mid-scoop filter to coax the short springs into behaving just a little more like long ones.

[Heemis]

I think my first plan of attack is going to just try and hack the reverb portion of the yamaha circuit board out and see if i can get that up and running.  I'm having some trouble finding the schematic however, so that might take a bit of tracing.  I will definitely post any progress I make as I think this will be a fairly interesting project when all is said and done.

I guess the better long term solution would be to house the actual "tank" in a separate enclosure, but I'm really just planning on using it for a very quiet solo project in which it will always be on.  I recently built up a tweed princeton clone and the lack of reverb has been harder to handle than I thought it would be.

That car radio reverb is amazing, just gotta watch out for potholes!

[theehman]

Try doing a google search for Pink Verb.  It was driven by a 386 (I think) and recovered with a 12AX7.

[Mark Hammer]

That car radio reverb is amazing, just gotta watch out for potholes!

You don't know the half of it.  What did people do for music in their car before there was cassettes?

This: http://www.mrhipster.com/randomness/oddfindarchive11.shtml

[petemoore]

  A little reverb helps out ... famous words, we used to run reverb on the stereo just because we liked it...of course depends on the material and the listener.
   Radio stations used to buy/use reverb on 'everything'...helps out !
  It's funny how many places reverb or delay circuits pop up, mic amps, PA's, Karaoke, 'players' of different things [keyboards, toys etc.].
   A recent 'new' entry effect had a small springset with some type of delay in a stompbox, this caught my interest.
  A fan of really long reverbs...but prefer middle to short delay tanks for rythm and clarity reasons, they seem to get thicker sounding reverb without 'endless' or 'intractable' delay.
   Though reduced mass in a smaller spring requires less force to move, the driver needs an amp which can control' it, it might not take much, a 386 can be wired up in about a half hour, finding the impedance to the tank input makes it easier to decide on an amplifier to drive it.
  Recovery is basic...boost the output to a 'level' which can be mixed, you can run pure reverb but will want a 'depth' knob which mixes the Rev output with clean signal.
   I'd consider figuring out if the board attached to the reverb tank can simply be powered up and used to drive/recover/mix the spring and clean signals.
    I had a very similar box w/same type of spring in it, but it had been exposed and was rusty. I wondered what rusty springs might sound like...
   12ax7 [12a_7...suggested alternative tube] seems excessive for a stompbox/reverb spring prototype, small signal devices do a pretty good job [recovery isn't that demanding IMO] and are a lot easier to work with.