Re: Cello duet 350
I am a HUGE fan of Cello and sold the gear (working for Mark Levinson and Joe Cali at Cello LA) before starting AVRev.com in early 1996.
My best bet would be to suggest you contact someone like Transparent Cable directly to have them make you custom cables. I don't think an adaptor is what you need as much as you need a cable that you can use as an adaptor.
Also look to Kimber Cable as they import WBT from Germany and they might have JUST what you need to get rocking.
Enjoy that Duet 350 amp. What a stellar component.
PS: Tom died in a car accident this past fall.
Jerry Del Colliano