Built the prototype today. It's about 90% there. I'm going to tweak the compander a bit and the modulation.
Scruff-you were right about the little extra gain stage I put between the two BBDs. It is not needed.
Can I possibly see your schematic? If you have an OpAmp/Half One spare, I think I may be able to make some use of it...
Plus I can hopefully help with your compander and modulation.
I think as we have the DMM, we may as well make this the most bad ass alternative possible, Analog delay with tails is already most of the way there.