Orange amps never cease to fascinate me. i love that elusive dirty tone - not fizzy, but with just that hint of harshness...
the TH30 is a great way to enter the Orange world, without spending a fortune, but it's a very peculiar piece of gear...
it has got 2 channels. an extremely loud clean with a 2 band EQ, that's very, very clean up to 12 o' clock, but can be driven into a really sweet (but ridiculously loud) crunch.
the dirt channel has lots and lots (4 stages, actually) of gain. even too much (fizzy to the point of being unusable after 3 o clock), and a shape control that can - well - shape EQ from a slightly nasal, middy and extremely smooth tone that reminds me a bit of Santana's mark amps to a metal-zoney mid-scooped adolescent idea of metal. between the two extremes there's a wide range of non-linear EQs. getting a completely satisfying tone is tricky and takes multiple attempts, but it's entirely possible.
the problem is, the first gain stage is weak and unremarkable. the fourth is chaotic and muddy. it's and the gain structure is not really ideal for rock.
it's a metal amp, great for doom and stoner (of course) and surprisingly good for black and even trash, if overdriven.
it has a non switchable fx loop (that works really bad with instrument level effects, beware!) and can be downgraded to 15 and 7 W (without losing much of its volume, but with much less headroom)
i modded mine changing the tubes for milder ones, and swapping a resistor to get a smoother gain structure (it's still a nasty beast, anyway), more similar to a Rockerverb. and it worked great (there's some info on the web).
i'd really love if the first gain stages sounded somehow as the pushed clean channel (did i mention it gets REALLY loud?). it would have been a much more versatile amp.