Here is a photo of the stereo Pikatron ÜP3096 (1:15) D.I. box we made. Such a simple and great sounding too for all kinds of different needs! Plus it gave me a reason to break out the plotter cutter. Pika! Pika!
Please take care of each other.
One thing I noticed when looking at spring tanks is most of the small units are plastic. I happened to find three of these all metal vintage 1970 ones. Not shown; I refoamed the center dampener and freshened the glue attaching the transformer cores/coils. Here is also a 1970 IC amplifier magazine clipping making reference to these tanks.
On a side note have you ever looked up the history and science behind the spring reverb?
Please take care of each other.
UPDATE: I did fond a Local source of magnets with the correct polar pattern for DIY spring reverbs. (SM Magnetics)
Please take care of each other.