Upgrade the weakest link. The in-akustik S25 BiWire Jumper replaces the stamped metal bridging plates found on most bi-wire speakers with a high-quality connection built on S25 cable series technology — 4-fold multicore OFC copper construction, 2 × 5.0mm² cross-section, gold-plated cable lugs, and pressure-grouted contacts. 150mm. Made in Germany.

The Weakest Link in Your Signal Path

To achieve the best possible sound, the amplifier must have the speakers firmly under control — driving the cones with precision and bringing them to a controlled stop with equal authority. The measure of this is the amplifier's damping factor. But the actual damping factor at the speaker cone is only as good as the weakest link in the signal path.

For most speakers with bi-wire terminals, that weakest link is the jumper bridge — the connection between the high-frequency and low-frequency terminals that allows the speaker to be driven from a single amplifier output. In the majority of cases, this bridge is a stamped metal plate: a simple, inexpensive piece of hardware with poor electrical properties, high contact resistance, and a construction that actively limits the damping factor that the amplifier and speaker cable have worked together to achieve.

The in-akustik S25 BiWire Jumper replaces this weak point entirely.

S25 Cable Technology — In a 150mm Bridge

The S25 BiWire Jumper is built on the technologies and materials of in-akustik's S25 speaker cable series — the same construction principles that define one of in-akustik's most respected high-fidelity cable ranges, applied to the specific demands of a speaker bridge connection.

At its core is a 4-fold multicore conductor structure with a total cross-section of 2 × 5.0mm² (achieved through four individual 2.5mm² conductors, each comprising 50 × 0.25mm strands of high-purity OFC copper). This sophisticated multicore architecture minimises the skin effect — the tendency of high-frequency signals to travel on the surface of a conductor rather than through its core — ensuring that high-frequency detail is carried to the tweeter terminals with the same precision and completeness as low-frequency energy is delivered to the bass drivers. The result is a more detailed, more controlled, and more dynamically coherent reproduction across the full frequency range.

OFC Copper, Gold-Plated Cable Lugs, 1.5-Tonne Contact Assembly

High-purity OFC (Oxygen-Free Copper) minimises contact resistance and ensures a permanently stable electrical connection that does not degrade over time. Gold-plated cable lugs extend this commitment to the connection points — gold's exceptional corrosion resistance ensuring that the contact quality remains consistent for the life of the speaker.

Pressure-grouted contacts assembled to 1.5 tonnes — the same connector assembly specification as in-akustik's NF-404 Micro AIR interconnects — create a mechanically robust, electrically stable termination with the lowest possible contact resistance. Stepped spade forks (6/8mm) accommodate a wide range of binding post sizes.

Every S25 BiWire Jumper undergoes individual continuity and short-circuit testing of all conductors before leaving in-akustik's factory in Germany.

A High-Quality Alternative — Even Without Bi-Wiring

Even in systems that are not running true bi-wire speaker cables, the S25 BiWire Jumper offers a meaningful and immediately audible improvement over the standard metal plates supplied with most speakers. Better electrical properties, lower contact resistance, more controlled signal distribution, and a construction built for audio performance rather than manufacturing economy — the S25 BiWire Jumper improves the quality of the connection between the speaker's terminals regardless of whether bi-wire cable is in use.

Feature Cards

🔗 Replace the Weakest Link

Stamped metal bridging plates limit the damping factor your amplifier and cables work so hard to achieve. The S25 BiWire Jumper replaces them with S25 cable series technology — for more precise cone control and a more controlled, dynamic sound.

🔬 4-Fold Multicore — Minimised Skin Effect

2 × 5.0mm² total cross-section via four individual 2.5mm² OFC multicore conductors (50 × 0.25mm strands) — reducing the skin effect and ensuring fine high-frequency detail reaches the tweeter terminals with full integrity.

🥇 Gold-Plated Cable Lugs — 1.5-Tonne Contact Assembly

High-purity OFC copper, gold-plated cable lugs, and pressure-grouted contacts assembled to 1.5 tonnes — individually tested for continuity and short-circuit on every pair. Made in Germany.

🔊 Better Even Without Bi-Wiring

Even in a single-wire system, the S25 BiWire Jumper outperforms standard metal bridging plates — delivering lower contact resistance, more uniform signal distribution, and better electrical properties at every binding post.

Editorial Blockquote

"For many speakers, the standard bi-wiring bridges — often simple stamped metal plates with poor electrical properties — are the weakest link in the signal path. The S25 BiWire Jumpers replace this weak point with a high-quality connection based on the technologies and materials of the S25 cable series." — in-akustik

At-a-Glance Bullets

• Replaces standard stamped metal bi-wire bridging plates
• 4-fold multicore OFC copper construction — S25 cable series technology
• Total cross-section: 2 × 5.0mm² (4 × 2.5mm² — 50 × 0.25mm strands per conductor)
• Minimised skin effect — detailed, controlled high-frequency reproduction
• Conductor material: high-purity OFC copper
• Dielectric: PE
• Cable diameter: 8.5mm
• Length: 150mm
• Connector: cable lug (spade) — stepped 6/8mm fork width
• Contact material: brass — gold-plated
• Connector assembly: pressure-grouted (1.5 tonnes)
• Individual continuity and short-circuit testing on every pair
• Colour coding: red and black
• Colour: dark blue jacket
• Beneficial with and without true bi-wire speaker cables
• CE, REACH, RoHS compliant
• Quality: Exzellenz
• Made in Germany

Specifications

Closing Quote

"A simple upgrade. An immediate improvement. The in-akustik S25 BiWire Jumper removes the weakest link from your speaker connection — and gives your amplifier the control over your speakers it was always capable of."