Folks: I received a matching quad from Grant fidelity (KT88) with an emission of 120mA. One was bad and had to be returned. It was replaced with a single tube at 130mA emission. I have been told by others that the use of tubes w/ different emission can hurt my amp. The tube dealer said it would be no problem. who is correct here? Is there a problem if one tube is higher in emission than the others?