I busked with a big band for six years, with my harp, amp't up. if you want the best-(bet I get me arse kicked for this) go to http://www.toaelectronics.com/ They do some gems, loads of inputs, 12v dc. 12v motorbike battery is best, the lightest. There I've done it now! If you want any more info, contact me john@harpmaker.karoo.co.uk John the harp. Be glad to help.