Hi Folks - I think there are two 'levels' of the old Roland Delay rack units - SD-2000, and maybe SDE-2000? Can anyone comment on which is more desireable, and why? I saw one for sale for $150 last weekend from an unadvertised private party and I can't remember which one I liked back in the '80's. The one I saw is the SDE-2000. Thanks in advance, Dana O.