I just got a Roadster but for years I have played a 5150. Someone from another board once told me to use a BBE 422 or 422A in the loop. No other sonic max. worked as good as the 422. I tried this and was so suprised, I could get tight chest pounding low end...I mean Recto territory. I had been using a Rect cab with it but the same guy recommended using the matching 5150 cab stating that he and friends tried many other cabs and the matching pair worked better. I found a used 5150 and tried it and it sounded even better. The 5150 is great for that one sound but only one sound. I still cannot believe a **** peavey being used to play metal!
I think tweaking my Roadster has been difficult because I still have the 5150 sound burned into my brain.