How do I make a rack reverb unit out of a spring reverb tank?

[Guite Lectrique]

Hi,

I have this old Peavey Bandit 65 that have a spring reverb tank in it. I want to take out the reverb tank to make a rack unit and add it to my live rig (which is a Mesa Rectifier Pre + 2:50 power amp). Would that be a simple operation? Would it work great in the effect loop of my preamp? And does anyone have a schematic for that?

Thanks

[Paul Perry (Frostwave)]

The hard part is, you need to have a circuit that drives the coil that makes the signal excite the spring, then have another (low noise) amplifier for the small signal that comes from the pickup at the other end of the spring. And signal levels are different for different springs.. and if you are not careful, you might burn out the driver coil & then it is worthless..
But, plenty of people have succeeded, and tehr eare circuits to be found.

[R.G.]

I have psychic scars from a couple of reverb tank incidents. It's not a simple thing to do.

I suggest you look up the "Center Stage" reverb circuit by Craig Anderton.

[Mark Hammer]

The quality and desirability of reverb often depends on where the split occurs.  Typically, the signal is split early on such that what the reverb pan sees is a less "tampered-with" version of the signal.  The reverb and otherwise EQ-ed, distorted, and adjusted version of the signal are then recombined further downstream.  Take a peak at the schem for your Peavey amp and you'll see that Realistically, there is always a lot of detail lost in the reverb.  Those springs aren't exactly the highest-fideltiy medium for transmitting sound, after all.  But, that being said, feeding them a *clean* bright signal, with a bit of dynamics (though not too much), is generally a good idea.

So, at what point do you do that?  When you feed a reverb pan with the output of your Mesa pre-amp, the chances are pretty good that it is already distorted, somewhat compressed, and whatever the EQ is, it probably isn't optimal for getting the best out of the springs.  remember that the reverb signal is added in the background to the foreground tone.  Often the way that the reverb pan is "pushed" is tailored to achieve something more like a light wash, rather than merely a full-bandwidth copy of the original, so as to place it more properly in the background.

I guess by now you can probably tell what I'm building up to.  While you most certainly CAN patch a reverb unit in between your pre and power amp, it may not sound the way you want it to, depending on how you like to set your amp.  If more distorted tones are your preference, then maybe the "best" place for reverb is to feed the pan from a point before the guitar hits your amp, and blend the reverb back in with the pre-amp adjusted version of your guitar signal at that patch point between pre and power amp.  With more dynamics in the signal you feed the reverb, you can control both the tone of the reverb and the amp by the way you pick, with a bit of differentiation between the two.

I should also point out that while some dynamics is good in the input signal fed to a spring pan, there are limits to how much dynamic range those springs can comfortably handle and many good spring reverbs come with built-in limiters, such that they get all the dynamic range below a certain point, but nothing above that point.  Something like the Orange Squeezer is a good circuit for that sort of job.  Not perfect, but close.

Finally,"best" reverb tone comes from having good impedance matching between the driver/recovery circuit  and the actual spring pan.  It will still "work" with just about any circuit, such as the Stage Centre Reverb, and a host of others (see here: http://www.solorb.com/elect/musiccirc/index.html ).  The question is whether you'll get the best frequency response and noise specs obtainable with that particular reverb pan.  So, the best place place to start is with impedance specs on the pan in question.  Then you can choose your circuit sensibly.

[jonathan perez]

i just found my old reverb tank...ill be building one, soon. thank you.

[tonefreak]

Here's another link you might want to check out:

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

http://sound.westhost.com/project34.htm

[AdamB]

weber speakers do an amp kit which is just a standalone spring reverb in a marshall head cabinet,

www.tedweber.com , I think it's in 'weber kits', then if you scroll down the page a little it's under '5G15' in the list of kits.

[Gladmarr]

http://www.zerotronics.com

I saw these guys' stuff in TapeOp a few months ago.  They use four Accutronics reverb tanks to create a stereo, balanced, passive reverb for mixing consoles.  Keep in mind, this won't do much for you as a guitar reverb, but it inspired me to run two reverb tanks into two channels of my mixer for a relatively low-level ambient reverb which works relatively well.