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RED Epic Power Voltage Drop Through Bolt Arm — 24V Stepdown Solution

Summary

Running a standard 12V power supply for a RED Epic (or DSMC1/DSMC2) through the Bolt arm's 3-pin XLR connectors results in too much line loss — the camera cannot be reliably powered. The voltage at the camera end is insufficient due to resistance in the arm cables.

The fix is to run a 24V supply through the arm and mount a 24V to 13.8V stepdown converter at the end of the arm, feeding the RED at the correct voltage.

Symptoms

  • RED Epic or DSMC camera powers on intermittently or not at all when fed from Bolt arm power cable.
  • Camera works normally on battery or when powered directly from a bench supply (bypassing the arm).
  • Issue is consistent with longer arm cable runs.

Fix

[CONFIRMED] Use 24V through arm + stepdown converter at camera end

  1. Connect a 24V DC power supply to the base of the Bolt arm (instead of the standard 12V supply).
  2. Route the 24V through the arm via the existing 3-pin XLR passthrough.
  3. Mount a 24V to 13.8V stepdown DC-DC converter (e.g. Cllena 24V→13.8V 20A 276W waterproof converter) at the end of the arm, close to the camera position.
  4. Connect the stepdown output to the RED Epic via a 4-pin XLR to RED 6-pin 1B power cable (e.g. Eonvic or similar).

The RED Epic/DSMC cameras run reliably at 13.8V. The 24V → 13.8V converter compensates for the voltage drop across the arm cable, ensuring adequate voltage arrives at the camera.

Confidence: 0.88 — confirmed by field operators (chunter_OhioHD).

Products used by the community: - Cllena DC 24V Step Down to 13.8V 20A 276W Converter (waterproof, available on Amazon) - Eonvic Male 4-pin XLR to 6-pin Female 1B power cable for RED Scarlet/Epic

Cable Notes

The standard RED power supply cable has 4 wires. For running through the Bolt arm's 3-pin XLR, the cable needs to be adapted to 2 wires. This can be done by intercepting the PSU cable with female and male XLR connectors.

For DSMC2 (Weapon/Epic-W/Helium/Raven etc.): the DSMC2 Base Expander is fully tested for full camera control from Flair (start/stop AND sync). Without the Expander, you may have to choose between start/stop OR receiving sync — not both.

For DSMC1 (older Epic/Scarlet): use the RED 4-pin Lemo to 3BNC sync cable for sync and control ports.

Source

Timestamp User Evidence
2023-06-18 dylanjamesellis "Do you have a recommendation for a cord connecting power from RED EPIC to the power supply on the Bolt Jr+?"
2023-06-23 chunter_OhioHD "When the Bolt is paired with an Epic, a 12V power supply run through the arm seems to incur too much line loss and can't reliably power the camera. To get around this we now use a 24V power supply to run through the arm, and then mount a 24V to 13.8V stepdown transformer on the end of the arm, which then supplies the RED with a voltage it can handle through a 4-pin XLR to Epic power cable."
2020-10-07 TimHC "The Standard RED Power Supply cable has 4 wires. Usually this cable needs to be adapted for 2 wires to go through the 3Pin XLR connectors on the Bolt Arm."