I'm a seasoned musician but brand new to bass guitar. My first bass is ordered but not yet received. I have guitar amps but want to get a proper bass amp. I have an ElectroVoice PA speaker system that features a 15" bass driver and mid/high frequency horn. I think the 15" driver is good enough to handle a bass. I'd like to get an affordable amp head to drive it. Affordable for me means $500 or less. What do you recommend I consider?