Unitra KG-40 2 x 4m
Overview
KG-40 cables embody the revival of an iconic brand in the Polish audio industry. These 4 mm² oxygen-free copper conductors are far more than a simple connection accessory: they attest to unique manufacturing expertise, where traditional craftsmanship meets the contemporary demands of high-fidelity.
A manufacturing process rooted in Poland’s textile tradition
The KG-40 stands out for artisanal production inherited from the textile legacy of Łódź. Its OFC oxygen-free copper conductors, arranged as two parallel twisted wires, are protected by a honey-colored Polish thread braid.
The braiding is performed on historic Polmatex-Majed machines, originally designed for silk and adapted here for cabling. Their sixteen-spindle process, slower than modern automation, ensures even density, pleasing flexibility, and optimal mechanical protection.
Electrical architecture and measurable performance
The KG-40 features electrical characteristics carefully optimized for the transmission of amplified audio signals. With a linear resistance of just 0.0049 Ω per meter, the cable minimizes signal losses even over long runs. This low resistance, combined with the generous 4 mm² cross-section, enables efficient power delivery—particularly crucial for demanding dynamic passages and low frequencies that require substantial energy transfer.
The parallel twisted-conductor structure is no accident. This configuration naturally reduces external electromagnetic interference while maintaining controlled inductance. The integrated aluminum separator adds an extra barrier against electromagnetic disturbances—especially useful in home environments teeming with interference sources (Wi‑Fi, phones, household appliances).
The operating temperature range, from 0°C to 80°C, far exceeds typical domestic use conditions. This thermal safety margin ensures stable electrical properties even during prolonged intensive use or in high-power amplification setups where cables may be subject to indirect heating.
Quality control and industrial validation
Every KG-40 cable undergoes a rigorous verification procedure using a Kikusui cable tester, a professional Japanese instrument renowned in the industry for its precision. The tests performed go far beyond simple continuity checks. Resistance measurements are carried out under a very high load current of 25 A in alternating voltage, simulating extreme usage conditions well beyond normal domestic use.
This industrial testing procedure—usually reserved for cables intended for professional equipment or critical installations—guarantees not only the electrical integrity of the product but also its ability to maintain performance over time. The Kikusui equipment used for these tests can detect resistance variations on the order of a thousandth of an ohm, ensuring consistently high production quality.
Gold-plated connectivity and universal compatibility
KG-40 cables are fitted with flexible gold-plated banana plugs, a technical choice that goes beyond premium aesthetics. Gold plating prevents contact oxidation—a particularly problematic phenomenon for audio connections, where even a thin oxide layer can degrade signal transmission. The flexible design of these plugs enables effortless insertion while maintaining optimal contact pressure, accommodating dimensional variations in speaker and amplifier binding posts.
These connectors offer wide compatibility with a broad range of terminals, whether traditional screw-type binding posts or modern locking connectors. The flexibility of the banana plugs also compensates for slight diameter differences between various binding post standards (European, American, Asian), consistently ensuring optimal electrical contact.
Availability and variants
KG-40 cables are available in standard lengths of 2.5 and 4 meters, with custom lengths available on request. This flexibility allows precise tailoring to each installation’s specific layout, avoiding excessive runs that can degrade the signal or create undesirable ground loops.
The Unitra range also includes the KG-25 model, featuring a 2.5 mm² conductor cross-section for installations that are less power-demanding or for shorter cable distances. This diversification makes it possible to optimize the cost/performance ratio according to the specific needs of each audio configuration.
Technical specifications
Materials and construction
- Cross-sectional area: 4 mm²
- Material: oxygen-free copper (OFC)
- Filler: flexible PVC compound
- Inner jacket: PVC compound
- Cable separator: aluminium
Electrical characteristics
- Operating temperature: 0 °C to 80 °C
- Linear resistance: 0.0049 Ω/m
Conductors and connectors
- Conductor type: parallel twisted conductors
- Termination: flexible gold-plated banana plugs compatible with a wide range of terminals
Frequently Asked Questions
What is the main difference between the KG-40 and the KG-25?
The key distinction lies in conductor cross-section: 4 mm² for the KG-40 versus 2.5 mm² for the KG-25. This difference translates into higher power transmission capability for the KG-40, making it better suited to high-power systems or longer cable runs. The lower linear resistance of the KG-40 also minimizes losses at low frequencies, which is critical for faithful bass reproduction.
How does the gold plating on the banana plugs actually affect sound quality?
Gold plating prevents oxide formation on contact surfaces, maintaining minimal and stable connection resistance over time. Unlike bare copper or brass, which oxidize and create a variable resistive barrier, gold retains its conductive properties indefinitely. This electrical stability yields consistent signal transmission, particularly noticeable in micro-detail and transient definition.
Does the aluminum separator have a measurable impact on interference?
The aluminum separator acts as a partial electrostatic shield between the two conductors. In urban environments saturated with electromagnetic waves, this additional protection reduces capacitive coupling with external interference sources. The effect is especially notable with amplifiers featuring high input sensitivity, where even minor disturbances can be amplified.
Are the cables directional?
KG-40 cables have no intrinsic electrical directionality. However, the parallel twisted-conductor structure and the aluminum separator configuration create slight geometric asymmetry. Some users report subtle differences depending on the connection direction, although these observations remain subjective and are not measurable with conventional instruments. Unitra does not specify a preferred connection direction.
- Eco-contribution included in the sale price.
- Manufacturer reference: KG40-02