The Parasound is $1999. A passive pre will not give you anything like the tube-like midrange that you seem to be looking for.
At your budget, and as @ghdprentice recommended earlier, you’re better off saving up $$$ to be able to purchase equipment that’s better able to achieve what you’re looking for. Frankly, for what you’re looking for and at your budget I’d be looking at a hybrid integrated from the likes of Unison Unico, Pathos, LTA, etc. The tubes don’t tend to get very hot in the pre section and have long lives. Plus, you can obviously roll tubes until you find just the right match for your Altecs if needed/wanted. FWIW.