You could try
switchcraft 860, but no guarantee. It is .150" OD, while duet barrel plug OD measures ~.133". I can't find anything nominal 3mm, but zillions at 3.5mm, so it could be that the duet plug is just on the cheap side of tolerance - in the words of the sage and prophet mccullinan, "idk..." Switchcraft 760 works perfectly in Squeezebox fwiw, but their ODs are identical.
Here's everything you need to know about
coaxial power connectors. I don't have tools to measure Duet connector ID but you estimate it with small drill bits. If you bring the receiver into rad shack, they will check if the standard 3.5mm plug will fit. Supposedly they have 3mm adapters also, size G (RS # 273-1710)
Once you know what you want, Mouser will have it. Switchcraft brand is an excellent quality connector, with nickel plated copper contacts, but no 3mm. I bet 3.5mm would work. Good luck
Rich
