c-j tube amps

what is diff. between 11a and 11xs ? what would be good value for used? also what is wattage/ohm rating.any help is appreciated.
11A 70 WATTS WITH 6550 OUTPUT TUBES---- 11XS 30WATTS IN triode using el34 output tubes. either should sell at aprox. 1700.00 used
What Ron8 says is correct. You can also peruse the CJ web site for more info or simply call them for more info.