I want to give a little love to my VOX Valvetronix VT-15 tube/combo amp. I usually play my Epi Dot Studio (an ES-335 down market copy) and get a lot of great blues tones from the clean, tweed and AC-30 settings. But I have been shopping for a tele, so when I try one out at the store, I plug it into the store's VT-15, and it sounds great. I default to playing blues licks, and both the guitar and the amp produce those tones naturally. It sounds great to my ears.
Most tube amps I have tried, esp Fender and Vox, produce great blues tones.