ba115hpt

I opted for the Ampeg BA115HP for my practice combo because it was $100 dollars cheaper than the BA115HPT (listening to them in the Noisy GC store, it was hard to justify the extra cost). For those of you that have tried both of these in other settings, does the "T" model warrant the extra $100...

I was able to finaly play through a BA115HPT and just loved it. It is hard to explain, but it is kind of like the sound is more "real" (don't know if that makes sense). How good a combo are these? Long term reliability? How frequently do you have to change the tube (playing maybe 4 hours a...