hi Bernhard. How about using one of those re-chargeable battery packs? I got one from Lidl here, with outputs of 9V and 12V. Ideal for my Zoom 2100. I like the little Washburn amps, but I don't think they're made anymore. Another idea is to take power from the amp to operate the loop device. andy ps. did you get mp3s on your cd webpage yet?