Hi AJ: if your amp is post-1950, the octal socket usually has a locating or indexing slot to accept the corresponding 'bump' on the side of post-war 6V6s bases. If you aren't certain of the orientation, I don't think you can safely put it in. Assuming you can confirm which is the 'right way', there's the matter of how much voltage the tube is rated for v. what your power supply is feeding the plate. Late 50s/early 60s A/B 6V6 amps typically run any where from 290V to 325V on the plates. Can you determine the plate voltage in what it came out of and compare that to the plate voltage of what it's going in to? We have a BBer who runs coke-bottle 6V6s but his are Mazdas; military grade tubes. Good luck! CJ