Hi John. I emailed preamp on installing a Marcus Retro in my bass – Marcus Miller Signature with Lindy Fralin pickups. Do not know if you remembered, I live in Sao Paulo – Brazil. Have you been all the the bass and installed can that was wonderful, very up of common Marcus Miller, simply the best! They were all amazed with the sound of the instrument and now they want their products in Brazil. Hugs.