sE Electronics FluxCore FCP1 – Hi-Z Passive DI With Stereo-to-Mono Summing

The sE Electronics FluxCore FCP1 is a passive direct box for engineers who need a DI that just works: no power, huge headroom and a custom transformer that keeps instruments, keyboards and playback clean and isolated. Its stereo-to-mono summing and 3.5 mm input turn a laptop or a stereo keyboard into a single XLR line. At Soundium it is the passive half of the new FluxCore series, alongside the active FCA1.

Key Features

• Custom-designed transformer: Pristine sound, high headroom, low distortion and full galvanic isolation between source and desk.
• Hi-Z input: A high input impedance keeps the load on connected instruments low, so tone and dynamics stay natural.
• SUM L+R switch: Mixes the IN/L and THRU/R jacks, or the 3.5 mm stereo input, to mono and saves a channel on your mixer or interface.
• 3.5 mm TRS stereo input: Plug in a laptop, phone or playback device directly, no adapter cable needed.
• Three-position ground lift with on+: Off, on and on+, which also helps suppress high-frequency noise and RFI on top of ground-loop hum.
• Built to mount anywhere: Non-slip mat, full-size hook-and-loop pad and four rack screws; up to four units fit side by side in 1U.

Customer Benefits

Because it is passive, the FCP1 needs no phantom power and handles serious level: up to 60 dBV with the −30 dB pad, so a bass amp speaker output or a hot line source will not break it up. The pad, polarity switch and THRU jack cover the everyday stage jobs, while the summing switch is the one you will reach for at every gig with backing tracks or a stereo keyboard. The matte-black box stacks neatly, stays discreet on stage and mounts on a pedalboard, a desk or a 1U shelf.

Quick Specs

• Type: Passive DI (no power required)
• Frequency range: 18 Hz – 30 kHz (−0.3 dB)
• Input impedance: 650 kΩ (pad 0 dB)
• Attenuation pad: 0 / −15 / −30 dB
• Gain: −20 dB
• Max input level: 30 dBV (0 dB pad), 60 dBV (−30 dB pad)
• Output impedance: 168 Ω
• Connectivity: 6.3 mm TS IN/L, 6.3 mm TS THRU/R, 3.5 mm TRS stereo input, 3-pin male XLR output
• Dimensions (W × H × D): 100 × 39 × 127 mm
• Weight: 795 g

In the Box

• 1 × sE Electronics FluxCore FCP1 passive DI box
• 1 × self-adhesive hook-and-loop pad
• 1 × self-adhesive non-slip mat
• 4 × rack-mounting screws

Ideal For

• Keyboards, synths and drum machines with line-level outputs
• Laptop, phone and backing-track playback on stage or in installations
• Active basses, acoustic guitars with preamps and amp speaker outputs

Compatibility

Works with any mixer, interface or stagebox XLR input. As a passive DI it needs no phantom power or batteries.

Pros & Cons

✅ Pros:

• No power needed and very high headroom
• Stereo-to-mono summing plus a built-in 3.5 mm input
• on+ ground lift tackles RFI as well as ground-loop hum
• Flexible mounting: desk, pedalboard or four units in 1U

⚠️ Cons:

• As a passive DI it has no gain stage, so very quiet passive pickups are better served by the active FCA1
• Single XLR output, so a stereo source is summed to mono rather than kept as two channels

For keys, playback and anything that needs to be quiet, isolated and simple, the FCP1 is the DI to keep in the case. Order the sE Electronics FluxCore FCP1 from Soundium, and add the FCA1 when a passive pickup needs an ultra Hi-Z input.