Hi, new to forum and would appreciate some help on this- I recently got a Caliber 50+ head and strangely it has boogie el34s in it and the schematic sticker on the back says 6l6s to be used. I have read that these heads never came in an el34 option....so my question is if somebody did put el34s in place, would the amp still make sound? Can I assume that it has been biased if so and would I be able to put 6l6s back in the head without a problem? It currently works with the el34s, but I do not want to damage it. Thanks