Hi there. I'm trying to use Rew+RePhase+Eq Apo with my current setup: Amazon Music via laptop=>Topping D50s=>Rotel Rb 1552 (sensitivity 1.5 volts)=>Wharfedale Linton. I have built up several filters and noted that with some of them the music sounds a bit recessed. So I thought to insert a preamp between the D50s and the Rotel in order to raise the level of the signal. Now I'm wondering how much gain do I need. If 6 dbs are enough, I could go with Topping A50s. Otherwise, I could choose the A90. Which is the best choice? See attached my Eq Apo filters. Thanks, eleo