I mainly play in a metal band and I'd like to save up for a nice head. I've never actually played through a tube amp but I've heard that the sound quality is far superior. I'm wondering what kind of amp heads should i be on the lookout for and what prices i can expect to pay. I've heard that an Ampeg SVT is a good head for what i am doing. Something that i can turn up the gain on and give a warm overdriven sound to my bass would be awesome. What are some good "metal heads" out there?