I got my used JVM410H yesterday. It's a great amp! I love the versatility it has to offer and the high gain tones are tight! The previous owner had it retubed and serviced recently so the amp now has JJ tubes in all the sockets. I did however notice that the clean and crunch channel didn't have quite as much gain as I was expecting from demo's I've seen. I also feel like the crunch channel is a little dark or I would like it if there was a tad more bite. So are there any pre-amp tubes you guys would recommend to get a little bit more gain and bite on the clean and crunch channels? I'm not a tube expert so mixing and matching is something I'd rather not do yet. I'd prefer to buy a set of tubes from one brand to start with. Any suggestions would be appreciated. Cheers! Edit: I think if I just change the V1 to an EHX for example I should already get a little bit more bite. Not 100% sure though.