I have a fretless ABG. It sounds great acoustically (nicely EUB like with tapewounds). The issue is that the preamp is a generic one and is all mids and spoils the amplified sound. I can tame it a bit with neutral amping and pulling mids out, but it's not ideal. Replacing it with something that will fit in the same cavity is going to be tricky. I have a soundhole pickup for guitar (Fishman) which sounds pretty reasonable on guitar but just results in boomy bass on the the ABG. One thing that occurs to me is wiring the piezo output direct to the end pin. I have an old Award-Session preamp which is apparently able to take very high impedance inputs, but that gives me limited EQ options and I haven't tested it as I need to find my adapters that take a 2.5mm connection which is the output of the piezo. Any recommendations or things to look out for?