Stage Center REverb

[petemoore]

  Had the circuit built and pretested last week, tank was waiting on the porch when I got home  !!!
  Fired up and sounded funny...cause was some bubble wrap touched the springs.
  I fixed that quick enough, then dialed for a minute to setup some nice vibrations, went back and forth with playing and diddling for a few moments, then was overcome with the need to play these forgotten tones and tunes....that took hours, gettting it into a box included another long test and admire session.
  [I used to have amps with reverb, after a while of being 'without', it's amazing how you don't realize how much you miss somehing until you have it again.
  I've been using 'medium generation and quality' digital reverbs, none have the livliness and character like these springs.
  All the time and money spent with the digital looks like a waste, considering what I'd had them doing [1 thing mostly all the time], varying depthe or mix to taste for room or song occasionally...I now think I was never getting all the cool tones, spending way lots more than a tank, couple OA's 'n pots, a few other things.
  Super effect, the Stage Center Reverb has plenty of thick depth, does the 'background Verb, really sounds great.
  I found the tank at Antique Electronic Supply, Short/3spring/Med to Long delay...sounds really great...once I got the bubble wrap off
  I used a 5532 for the OA Driving the tank input.
  I 'furbed' the old tank with a small speaker replacing the input transducer, wired the cone to springs...actually worked !!!...needed work, especially in bass whoomph taper...was getting there though, a HF driver with very small cone would probably have helped it, it'll be sitting there...lol.

[jrc4558]

Hi, Peter!
What impedance is your reverb tank?
I tried building this effect but it came out really bad and I suspect the reverb tank input-output impedances to be responsible...

[petemoore]

    310 ohm input, 2,575 ohm output
  IIUC the input is the one you need to worry about when using a SCR OA to drive it.
  I blew the input transducer on the old tank.
  I replaced that with a speaker, just for discussion purposes, the transducer is basically a modded speaker coil driving the springs mechanically.
  Someone mentioned an LM386 for driving reverb tanks with input impedances OA's have trouble driving, makes sense considering how a 386 can drive a 10'' speaker...
  I tested the input by putting a signal through it and amplifying it to sound, same with both sides of mix and output.
  Again,,..IIUC here, if you have that, probably the only thing left is to get the input transducer moving, I don't know exactly how, probably doesn't need all of what a 386 can deliver, but beefing the output to match the impedance, and a relatively low gain setting on the 386 would I think get you there, I think the transducers are sensative to overamping though, you'd want to be calcing or closeley monitoring the sound I'd guess.
  Wasn't there a schematic for a 386 based Reverb around..., you might want to try searching.
  I had a small pedalboard finished, just happened to be fitted well for mounting the cases [for springs and a raco for circuit] on. So everythings secured and tight.  I might put a covering over the whole arrangement..
  A second voicing mod for reverb would be a good switch to have on it I think.

[Eric H]

That's great, Pete!
I have an old tank out of a 60's Gibson I've been meaning to try that circuit with.
Just have to make some time.

-Eric

[octafish]

http://sound.westhost.com/project34.htm
Lm386 driven reverb

[Mark Hammer]

Here is another that works fine.  All discrete (with the exception of the 386).  Runs off 12v (don't recommend 9v battery here).  Includes provision for mixing wet/dry.

http://www.solorb.com/elect/musiccirc/reverb/index.html

[petemoore]

  Further tryouts reveal that headroom, [pretty sure it's the drive cct. for the tank input], is at least sort of an issue.
  Playing it with a slightly older Rechargable, with a nice tang taste to it, and twisting on the transducer circuit gain knob [seems like what it is, hafta look again], induced/got rid of what sounded like OA clipping to the spring driver.
  Replacing that battery with a fresher charged one that tasted about the same, maybe slightly 'tangy-er', allowed more drive to be obtained with that knob.
  Still has a touch of 'nastiness' if I'm using Neck HB and strumming chords, also if I put a Boost/Fuzz in front of it, volume must be kept near unity to avoid that.
  I'm thinking...power supply voltage increase, or Opamp Choice for the transducer driver. The NE5532 is outperforming a 'standard like TL082 or 4558.
   I'm wondering if there's an OA that'll have enough 'uumph' to drive the transducer and get closer to the PS rails [?].
  Or if there's another possible solution [provided this IS where the problem lies], such as a buffer or other method of increasing drive/headroom.   
  EDIT:
  Actually I Put in the NE5532 in the second opamp position, that one drives the reverb tank, and that helped it out just fine, N/p' works very much as intended, and that's really good.
  The 'issue' is that this puts a solid state input 'south' of FF, so the FF doesn't sound so good. FF placed after Reverb is certainly 'different, howling sustains are cool...So far of all my Dist builds the BSIAB II is doing the best of the batch, but I haven't tried say a Mosfet or Jfet boost between the FF and the Reverb unit.
  Synopsis is...Reverb sounds great, but Fuzz Sounds aren't doing so well as of yet.
  ADDENDUM
  I found two ground problems, one was the jax Gnd never took solder, I guess all the shielding around the boards ground wire kept it from taking, also classic jack looseness, this must be one of the early RS jacks I let the sleeve spin, I think by holding the ground lug from spinning into the tip and at the same time pressing on the sleeve that is sort of 'rivetted' I got it pretty tight this time.
  It's sounding wonderful with SS Phase>FF low-er vol set>Mosfet>SCRU>DYNA Power Amp>2 x G.back 25's.
  On the RCA test amp, alone, this thing does a fabulous "Brian Jones". It gives a whole new meaning to my Clean one note quick Zep Type lead phrase bends.
  It's a little bit funky to run Fuzzes with at this point, all my Fuzzes have been tuned to amp inputs, and the digital reverbs I was using didn't seem to particularly 'mind' a FF, altering it's tone somewhat, but generally nice and acceptable.
  I think with some tweeking of FF/Fet output to drive the opamp input I can get something cool happening.
  It seems to chow batteries a bit...it could do with a better PS.