I've ordered the xs400 1x15 combo. Thanks to everyone that helped out with making the decision. Ive got a couple of questions about it. Could a Yorkville 210 sit on top of the 115 combo? I would prefer to have the tens higher. Also, I've heard that the compression on the amp isn't all that good. Any recommendations for a compression pedal? Would any particular one work best with this amp? Also, which pre-amp tube should I replace the stock one with when it's ready to go? How much would it change the sound?