Trying a KR 300b in Canary mono blocks 330 MKII

Has anyone tried KR 300b just the 300 not the xls or mesh just the regular 300b in a set of Canary amps ...whn I first bought them from Canary I was told not to use KR ? Don't want to damage my amps but want good hardy tube for longevity KR or emmison lab ? Thanks all ! Alberto