You should be able to get a TLC-1 for less than $500. Passives are not for everyone though. While passives are tempting to those on a tight budget, generally it's a bigger crap shoot. Definitely try both actives and passives with the rest of your system before you buy.
Frankly, for your max budget of $900, I'd see if you could get a good deal on a used McCormack RLD-1 or Rogue preamp. (I think they both have a second set of outputs for your sub and also a remote.) At their price points, you are very well set.
Also, I know Steve McCormack is now modding the RLD-1 and, of course, your DNA.5, so you'd have alot of versatility in the future as your budget and needs allows.
Frankly, for your max budget of $900, I'd see if you could get a good deal on a used McCormack RLD-1 or Rogue preamp. (I think they both have a second set of outputs for your sub and also a remote.) At their price points, you are very well set.
Also, I know Steve McCormack is now modding the RLD-1 and, of course, your DNA.5, so you'd have alot of versatility in the future as your budget and needs allows.