I noticed that many mixers such as the Behringer hard wire their line inputs (without even a switch) in parallel with the mic input to the mic preamps. Yes, they do have a drop resistor but that's all. My concern is that the signal is being dropped and then amplified back up - thus adding another stage and more noise.

Is it really necessary to connect a mic through a preamp first if a dbx 106A is next in line in the chain? I'm just recording guitar and vocals for home demos. I know an Avalon preamp would sound great but I don't have money to burn. I really don't want to buy an Audio Buddy either if it's not gonna be noticeable if I connect straight into a dbx 160A.