2 layers32 × 4 mm

Piezo preamp single
compuphase/piezo-preamplifier
High impedance preamplifier for piezo pickups
12 parts3
Boards in 1 GitHub repository, designed in KiCad, that use the OPA1677D by Texas Instruments (-18V~-2.25V、2.25V~18V -40℃~+85℃ 0.0001% 1-Channel 2.5mA SOIC-8 Audio Amplifiers ROHS). See how each wires it, with its parts, size, README and files; the OPA1677D’s symbol, footprint and pinout are on its own page.

compuphase/piezo-preamplifier
High impedance preamplifier for piezo pickups