sub woofer and tubes

question for all you audio buffs? i have a fisher x-202-b integrated amp and i just recently hooked my sony self powered sub up to it to see how it sounds. i used the center channel record out rca port. well the question is with my amp running hot with the sub about four feet from the unit will the ultra low vibrations vibrate my hot tubes and damage them? i am really just doing this for fun and will probably take the sub off the system soon and put it back with my surround sound unit. but am i doing harm to my system by exposing those hot hot tubes to ultra low noise. i guess im thinking that when they heat up especially the output tubes are they like a lighbulb filiment and are they fragile. for now its kind of fun but does sound very sloppy.
peace out
I don't see much of a problem but I would use the main outs with "Y" cables and it should be crossed over as low as possible to keep it from being sloppy.
Yes, I would say that subjecting your tubes to vibration (through floor and air) is a bad idea. It's not so much that it will damage them, but it will screw-up your sound.
Use a longer cable to the sub and move it somewhere else. Make sure that the Fisher is isolated on a good damped stand, and if you do decide to use a sub near it full time, invest in a tube damper accessory like Herbie's Halos.