StompFork

This project is about an active audio signal splitter that utilizes the TL074 opamp to drive multiple parallel stompboxes.

Key features

• Split one line-level input into three outputs
• Direct output (unity from input buffer)
• Stompbox output 1 (level pot + output buffer)
• Stompbox output 2 (level pot + output buffer)

Power supply

• Recommended 18 V
• Should work at 12 V
• May work at 9 V
• Series schottky protection included

Impedance

• Hi‑Z input (~1 MΩ AC)
• Lo‑Z output (~100 Ω AC)

Thoughts

1. The circuit should fit on a standard 100x50 mm perfboard. You can save even more space by combining several smaller JST connectors into one larger one.
2. Prefer TS patch cables or TRS jacks with R tied to S.
3. Depending on the signal path, isolation will probably be necessary:
   1. Isolate input using the LEHLE P-ISO, P-SPLIT or HZ, MZ transformers.
   2. Isolate outputs similar to the Radial X-AMP.

Caps

Depending on your preference, you can use polarized electrolytic caps in the signal path, or you can replace them with "audiophile" film caps. For this purpose, the KiCad project includes larger footprints for C1 and C5-C7.

If you decide to use the polarized electrolytic caps, ensure that the anode + is facing the opamp and the cathode - is facing the jacks.

Either way be sure to pick a sufficient voltage rating, e.g. 50 V.

Similar projects

• The Splitter Kit by Das Musikding
• Signal Splitter by Guitar Electronics

Further reading

• Designing With Opamps by Rod Elliott
• Schematics by Jensen Transformers

Example build