I did the FX Loop Mod to 47pf, and the mud mod, and it just woke the amp up, sounds much better.
Very easy to do with good results.
Last mod forme is swapping out the black shadow and putting in a vintage 30.
This amp sounds killer thru my 4x12 with vintage 30s.
I recently picked up a Nomad 55, and I am using the Groove Tubes Substitubes in it with EL84s, which really complement the nature of this amp. I find it to be more balanced now, and ofcourse a little more Brit sounding, which is my preference. (I liked the Nomad better running EL34s in it)...
I have nothing but positive experiences with Bob and JJ tubes. Not one has failed, and I always get an improvement in tone, and they have been very helpful in answering questions.