So I am really more of a hot rodded Marshall guy. The stock MT15 is great but still not ideal for ME. I changed some of the pre-amp tubes (still waiting to receive a 5751) and a Mullard in V2 improved things. I still felt like things could be better though. I had a Crate Blue Voodoo many years ago that had great tone with 6L6's but when I switched to EL34's it was MUCH more to my liking, so why not try for magic again with the MT15. I went over to my good buddy Rider's house and he did the swap and biasing for me. The result was a much more Classic Rock tone (Marshally) but with gain to spare. I will still try the 5751 in V2 to reduce the gain a bit. It is great to have a super light and portable amp that has two channels and a loop with enough volume to knock a house down - all for way under $1000!!! I have said this before it's the best buy out there by far!!