sE Electronics FluxCore FCA1 Caja DI

Active DI Box for Sources That Need a Very Light Load

The sE Electronics FluxCore FCA1 is an active 1-channel DI box with an Ultra-HiZ input stage that presents up to 10 MΩ to the connected instrument. Passive magnetic pickups, piezo transducers, and vintage high-impedance microphones can change their tone when loaded too heavily. The FCA1 keeps that load virtually negligible so the source reaches the console intact.

What Sets the FCA1 Apart

The LOAD switch offers three input impedance settings — 10 MΩ, 100 kΩ, and 10 kΩ — letting the engineer dial in the source-to-DI relationship. sE's DYNAMITE technology provides switchable 0, +15, and +30 dB of ultra-clean gain for low-output sources.

Input Stage — Impedance, Gain, and Pad

Switchable impedance and gain give direct control over how the source is loaded and how much level reaches the next stage.

• Input Impedance: 10 MΩ, 100 kΩ, or 10 kΩ at 0 dB pad
• DYNAMITE Gain: 0, +15, or +30 dB switchable
• Attenuation Pad: 0, -15, or -30 dB — pad settings also change input impedance (12 kΩ at -15 dB, 10 kΩ at -30 dB)

Output Stage — Balanced Signal and Ground Control

The output stage converts the high-impedance instrument signal into a balanced, isolated feed.

• Outputs: Balanced XLR, Unbalanced 6.3 mm TS THRU — transformer-balanced, galvanically isolated
• Ground Lift: 3-position switch (OFF / ON / ON+) — ON breaks ground for hum loops; ON+ suppresses RF interference
• Polarity Switch: POLAR — aligns phase between direct signal and a miked amplifier

Power, Build, and Mounting

The FCA1 requires +48 V phantom power — no batteries, no external supply.

• Power: +48 V phantom power — front and rear LEDs confirm presence
• Dimensions: 100 x 39 x 127 mm
• Weight: 0.8 kg
• Mounting: non-slip pad, hook-and-loop pads, or up to 4 units on a 1U rack shelf