Hi - I am looking for a non-obtrusive way to take two basses and run them into my amp. I would like as much transparency as possible from the DI/preamp. Both basses are passive. I'm running - NS WAV 4 and a stock Jazz bass into Ampeg Portaflex 500 head - Carvin 4X10 Red-Eye Cab. My issue is that the Portaflex only has one channel. So I am probably going to set the amp as flat as possible and then tweak the two basses with the preamp. Of these two products, what are your thoughts??