DIY Spring Reverb Rack?

[E-money]

This was 1982 folks. The only part I found back then that worked as a compander chip was the NE570.

I also used that part in 1988 when I designed a PWM subcode audio noise reduction scheme for Hasbro video games. I got about a 90 db s/n from using the 'black bars' between video frames to bury the subcode in.

Jim Williams' posts never cease to blow me away.

[floid]

Dbx units such as the 122 and 124 are a dirt cheap way to get basic expand/compress/normal functionality both pre and post tank. plenty of spring tanks even have rca connectors, about as plug and play as it comes.
don't know whether this is optimal/safe, but my pair of homebrew altec (1567? forget the model #) style tube pres seem to work well as driver/recovery amps for the tank i pulled from an old wurly organ.

[Magnetic Services]

The Spring tank in my amp is on the fritz, and I've thought about trying to modify it to fit in a rack chassis as well as add capability for different levels and impedances... It's an Accutronics 3-spring and if someone tries this and posts pictures I will follow along and post my own!

[Gilroy]

this could be a lot of fun. I have a few tanks kicking around from some old noise performances I used to do, would be good to put them to better use. thanks for all the info!

[germaniac]

Dbx units such as the 122 and 124 are a dirt cheap way to get basic expand/compress/normal functionality both pre and post tank. plenty of spring tanks even have rca connectors, about as plug and play as it comes.

Using a DBX unit with a spring reverb tank is a good idea--at least I thought as much when the same idea occurred to me, but then didn't work out in practice. . . .

There's no problem on the compressor side. But on the expander side, since it wants to make loud sounds louder and soft sounds softer, it severely shortens the long, slow decay of the springs to a sort of dull thwonk. The core of the problem is, for companding to work right, the information between the comp and expander can't be interfered with, otherwise tracking goes out the window. But following after a reverb tank, obviously the expander's input is seeing a signal that's heavily altered from the compressor's output.

AFAIK, there's no way around that problem. You could change the decay of the expander, but then what you'd be talking about is just an ordinary noise gate. I wish there was some easy way like a compansion scheme, but the only way I can see to really effectively remove the tank noise is with some kind of humbucking coil configuration. . . .

[floid]

expansion post-spring, yea not always too great. but pre-spring, w/ compression post, can be tasty.

i use a dbx 124, the quad unit w/ seperate control over the front and back pairs. take the spring input from a front channel, output to a back channel, now try button combinations - flat/flat, flat/compress, compress/compress, etc. send and return levels are all important, especially when expanding on the way in.

[johnblue]

i am dreaming up a mod to my pioneer sr-101... looks easy enough.

there are some guys who explain how to make it a true dual mono. the tube preamp section is easy as pie... you all should take a look at it.

i got the unit for 100, they are around.. going to switch out for the full size spring tanks though