The problem probably isn't your head. My moneys on the cab. The problem with the Ampeg 8x10 is that it hasn't changed in like 60 years. Im sorry to break it to Ampeg, but times change, and the music world is changing constantly to keep up with the vast styles of music today.
The problem is that it's range of frequency isn't the best. If you look at
musicians friend, it lists the Ampeg with a frequency response from 58Hz-5KHz. In comparison, looking at the Basson 8x10 on the same website, the frequency is 28Hz-5KHz. As you can see, 28Hz is a lot lower frequency that 58Hz, almost half! Your going to get a lot more low end from the basson. Im not trying to put Ampeg down, but there are other cabs out there that can do what its doing, only a lot better.