Hi all! I've got an Ampeg SVT-IIP preamp which I'd like to put in a rack. The manual states 'Be sure unit has proper ventilation by keeping top, bottom, side and rear free of obstructions. One inch clearance is recommended.' Is this really all that necessary? It'd mean this one rack space preamp would take up three rack spaces >_< Can I get away with putting it in the top slot of a wooden rack with a power amp directly below it? There are vents on the top and back for the three 12ax7 tubes. There aren't any fans in this thing. Or do I need a bigger rack and have the top slot empty for ventilation?