If you're a Dead Head, you'll probably be interested in this one. It's the pre-amp from Jerry Garcia's Tiger guitar used from '79-'89 and built by Doug Irwin. It's a unity gain buffer to prevent signal loss with long cables. It can be built into a guitar like the original or into a 1590A. Other single op-amps can be used instead of the LF356N (TL071, NE5534, etc).
This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.