I'm looking at an Ampeg B15-N tomorrow after work. Why do they call it a flip top? Is there anything I need to know before I buy? This thing had a transformer replaced 15 years ago, and it had a 3 prong power cord added recently. I've played with one using a vintage J bass and liked the tone. I'm going to be using it with my Stingray, and a Godin A4 fretless hollow body. The Stingray has an active Humbucker and the Godin has a pre-amp built in. Are they going to sound alright through a 50 year old amp?