OK, a week late, but here are the pics. Here's the tutorial, in Lovekraft's own words.
NOTE: This tutorial assumes a familiarity with basic soldering practice, component identification and orientation, and electronics construction technique - furthermore, no warranty, explicit or implied, is given regarding the suitability of this project for any given purpose, nor does the poster accept any responsibility for any damages pursuant to the assembly or use of this circuit. Proceed at your own risk.
OK, having gotten that out of the way, here's a relatively simple, inexpensive buffer circuit suitable for using to mix passive pickups with EMG active pickups, or buffering piezo pickups to mix with magnetics. Frequency response is pretty much flat, and noise is fairly comparable to passive pickups if built correctly. The circuit will easily drive a load of 10K or lower, so even long cable runs shouldn't be an issue. Here is the schematic:
The following are also available for download:
1. A Vero board layout
2. A Bill of Materials (including Mouser part numbers)
Part QTY Mouser #
C1 1 581-BF014D0224J
C2 1 581-BF074D0684J
R1,R2 2 660-MF1/4DC1004F
R3,R4 2 660-MF1/4DC1002F
Q1 1 512-2N5457
Q2 1 512-2N5087TA
misc vero board, solder, hookup wire, etc.
3. A construction diagram
Finally, here's a photo of an earlier build of this circuit, thrown together hastily with "found" components a while back for "proof-of-concept" - the newer layout posted above is both smaller and cleaner, but at least this will give you a rough idea of the size (that's a US nickle in the pic, for scale).