Simple OnBoard JFet Preamp for Piezos - Cigar Box Nation
Source Audio Release ZIO, An All Analog PreAmp Front End + Boost Guitar Pedal — Noisegate
DT JFET Preamp | Details | Hackaday.io
JFET guitar/instrument buffer pedal – Stompville
Guitar Pedal X - GPX Blog - Horrothia's Triage Discrete All-Transistor JFET Pre-Amplifier is a Beautifully Elegantly Textured Low to Mid Gain Overdrive
For both live and studio. jFET preamp/overdrive with parallel compressor and DI. - YouTube
Source Audio ZIO Analog Front End Preamp & Boost Guitar Pedal - Cottonwood Music Emporium
Simple JFET Preamp for an iDevice Guitar Interface – Planet Z