Answering my own question:
"It’s the culmination of five years of R&D harkening back to the 1745 DDL, the original Digital Delay Line. Rose is our first stompbox to exploit this new/old way to ‘do’ delay. There is no digital signal processing as such. Just a long, pristine, swept delay. Analog circuitry does the rest.”
The Rose sounds inherently different because of its unusual design. The delay is derived from a variable digital clock that can be swept over a range of ~200kHz for maximum fidelity with up to 10 seconds of delay, down to ~8kHz for 50 seconds of delay. All of Rose’s analog circuitry is employed for mixing, filtering and feedback.
This is an interesting look at the original DDL tech it has grown out of, with really cool old photos.
As, I noted earlier, the sound in the demo didn’t really appeal to me, but I think the tech is really cool, so I’m interested to hear more demos. (Also, I wish it had the asthetic of the old DDL-1745, I probably would have bought one for that alone, lol).