It is indeed really good :)
My engineer friend built it actually. He did some mods here and there:
-rft spring tank - not in production anymore, it has a wider spectrum than the accutronics 3spring..
-15V power for loudness
-power source is outside the box (he built the whole thing into a 1U high 19" wide disfunctional multieffect processor)
-he also changed one ic on the a-199 to make it less noisy
-it took him 4 days approx. to build it

i can ask you about other details too, msg me any time.
also, i have checked one topic on muffwiggler - one of you directed me there too.

as for the tank - i cant really help you out with anything much but: "look for a used one", because to the best of my knowledge these tanks aren't in production anymore...

András

--- In Doepfer_a100@yahoogroups.com , "Lars" <lahebr2000@...> wrote:
>
>
> Sounds really good! How did you build the springverb I have the A-199 and have been thinking about connecting it to an external spring.
>
>
> /Lars
>
> --- In Doepfer_a100@yahoogroups.com , Andras Hargitai <andras.hargitai@> wrote:
> >
> > Dear A100ers,
> >
> > I am glad to post that the custom built spring reverb driven by the
> > a-199 is ready... It does sound amazing!
> > If you have the time and interest, here is a little test with a
> > Vermona drm-1. :)
> > https://soundcloud.com/banyek314/east-german-spring-tank-test
> >
> > greets,
> > András
> >
>