Trying amps in Denver or Boulder, Colorado

Your best bet is probably Drum City Guitarland in Denver. They have a somewhat limited selection for bass guitar but usually have stuff you won't find at Guitar Center. Otherwise GC is the only other place with any sort of selection that I know of. There's also Gravity Music Gear but that's hit or miss because they deal strictly in used equipment.

I just moved away from Denver, otherwise I have a few things you could have tried. Best of luck!

 

Music go round has some used gear as well but the selection is usually pretty rough and not worth checking out. Gravity is better in that regard and is pretty good about putting up what they have on their website and Craigslist to save you from driving in. Like pravus, im only aware of drum land and GC for new heads and cabs and the selection is very minimal. Pretty much stuck buying online if you want new.