ok guys/gals, i happened to come cross a Kris 300m mobile tube amp today. and was wondering if they were any good? it seems to be in good shape. the tubes look pretty new. havent got a chance to test it out yet tho. i beleive it has 2 6uj6's. but, was wondering if i could replace them with 6lq6's or somthing like that. also, i was wondering how difucult it would be to tune this old thing. i was wanting to put it behind my mgnum S-6. keys 3 swings bout 45, with a preditor 10k antenna. thanks all.