Guys, I'm shopping for an inexpensive but powerful and good quality power amp. Here are the two I'm considering. QSC RMX 850 and the Carvin 600 watt power amp. People who have played through both with bass rigs please give me advice. Which one will leave the sound from my preamp the most uncolored? I love the tube sound, and my next purchase after this is going to be the Ampeg SVP-Pro, so I want an amp that will leave the tube sound very clean. Thanks. Dirk.