Likewise I love my HT5 head. I wasn't as keen on it clean (came from a Minimat), but a tube swap for an RFT and Brimar combo made a big difference to that. Particularly the RFT in the pre stage. I spent the weekend trying all sorts of cabs and drivers and am going to swap the driver in my 1x12 to a Mesa MC90 also as that really sorted it out also. The Hot100 has tonnes of bottom end but doesn't have the top. G12H Heritage's have amazing mid and top and little bottom (in comparison), I tried a 2x12 with a Gold and Heritage in it that sounds incredible with a Laney (just balanced and bloody lovely across the whole frequency range) and it sounded a bit shite on the blackstar. Then an Eminence basslite that I have lying around that used to sound brilliant on an old solid state crate I had for a few weeks, but that was all bottom and nothing else with this. Just because it was there I plugged it into Marauder's recto combo and that nailed it. It hasn't quite got the bottom end of the Hot100, but it's pretty damn close, and hasn't got as nice mids/top of the Heritage. But it does make a bloody good stab at it.
I still stand by my opinion that for a home use only head, there's really no touching it for the money if you like high gain. I have no doubt there are better clean amps, but for an all rounder, with the RFT (made a far bigger difference than changing the power tube) and the Mesa (when the next one pops up on ebay for £50) I'll be quite happy with it.
