Phil Jones Briefcase non-aux challenge!

[highwayman]

I'm seriously considering a Phil Jones Bass Briefcase amp as it suits most of my requirements; the one area it seems to be lacking is the inclusion of a 3.5 mm aux input to play my phone through.

PJB's importer has suggested a Rolls 22MXb Minimix line mixer as a potential solution, though I notice it requires an additional power source - something I'd rather avoid, especially if I use the Briefcase's battery-powered function whilst out and about.

I'm looking for a small, simple, high quality (preferably affordable) solution that can take 6.3 mm jacks from the Briefcase and Stingray and my iPhone's 3.5 mm jack and that doesn't require a separate power source. Suggestions please!