I'm daydream planning my next amp rig. Gonna order up some flat pack fearful kits in a week or two. Meanwhile it got me thinking I'll need more than the 500w my GK micro head is providing. I'm thinking 1000 or so. This put me in mind if just getting a rack mountable power amp...and a preamp to drive it. I know nothing about separate component preamps. I'm aware that you can get them rack mountable or pedal style. Pedal appeals to me. And I'd be looking for basic tone shaping and if it had some kind of usable drive that's cool too. What puzzles me is ... how much umph do they need to have to sufficiently "drive" a power amp? Do they have watt output ratings? How do I know if, say, the MXR M81 is going to do the job? Is it designed to bring my level up to where a power amp is going to be efficient in driving my cabs? Do rack mount pres have DI outs? Or any of the niceities you find in traditional bass heads?