For battery operation I use either a ZVex LoFi Loop Junky http://www.zvex.com/junky.html or a Boss RC20XL (or both) as the looping device, into an Electro Harmonix Freedom Amp . http://www.ehx.com/ehx2/Default.asp?q=f&f=%2FCatalog%2F44%5FFreedom%5FAmp > I'm not mentioning the Boss RC-20 and RC-20XL because they don't allow to > control Feedback: it's always at 100%, right? If you discount the Boss for this reason, then you won't like the ZVex either, since it's the same. Are you sure you're looking for a looper and not a long delay?