The other option is to make your own voltage reducer out of solid state parts, any electronic supply house should have a LM78H05 which is a 5V 5A three terminal positive regulator (-gnd) a couple of 1N1004 diodes and a couple of capactors and a heat sink. For + gnd use an LM79H05 instead, the 2 diodes connected in series to the ground pin of the regulator will increase the output voltage to 6.4V out @ 5A. the capactors are 1uf 20v one from the input of the regulator to gnd and the other fron the output to gnd.
