Looking for a 4-ch mic pre upgrade to the pres' on my Yamaha AW1600. No surprise, requiring more gain for a few mics (using SM57, AT3035 and Senn 421 at the moment for percussion - congas, keys and vocals) in my home studio. Desiring a mic pre with neutral affect on the mic signals. What would be the next reasonable stage up from the AW1600? I recognize I could go 'whole hog' and spend $$$'s on a few namely pres that will do this, but I'm unaware of the current market for less expensive options. I had, and am still considering the Grace 1-ch for vocals, and making do with other inexpensive alternatives for the other channels, but would be nice to make a leap to a 4-ch unit that would suffice for a while. thanks for any and all with this.