And I am pleasantly surprised at just how good it sounds. I have built an 18W 1974 combo before which sounded great, but this sounds better.
One of the big things for me is low-end. I loved the 1974's tone, but it didn't have any thump to it. It sounded very "Marshall-lite". The Trinity Plexi has sorted this and when I play through my small Mojo Marshall-style 2x12 combo cab (open back) I am getting a big, muscular sound. It really sounds like an old plexi. Wow.
The only ways I have deviated from stock are: carbon film resistors instead of the supplied CC; PEC 2W pots; F+T electrolytics (because I like them and because the big JJ wouldn't take solder well) and I didn't use the bright cap on the first channel. I think the kit is outstanding value. I have ordered a small head cab from Mojo (I am in Australia which makes cab shipping very expensive).
I'm playing it through a Celestion G12M Creamback and a G12H Heritage. They are the speakers I have left over! My two least favourite speakers, but the amp sounds amazing through them. So far I have only played my Luther Dickinson 335 through it - it's a 335 with dog-ear P90s and a bigsby. It sounds huge and articulate through this amp. I don't think I will be modifying the amp in the near future - it sounds wonderful as-is.
You Trinity fellas have done a great job with this design. Well done!