The Supra Classic 4 Blue is a 2 × 4 mm² speaker cable designed by Jenving Technology AB, a Swedish manufacturer active for nearly fifty years. It features internationally patented tin-plating technology and a multi-strand structure composed of 511 conductors per channel. This model is intended for audio systems that require a large cross-section and a low-resistance conductor, while maintaining an accessible price point.
The design of the Classic 4 Blue is based on rigorous engineering principles rather than marketing effects. Each conductor consists of 511 concentric strands, each 0.10 mm in diameter, made from OFC (Oxygen-Free Copper) with an exceptional purity of 99.999%—a 5N quality that ensures optimal audio signal transmission. This multi-strand architecture provides remarkable flexibility for installation, even in tight spaces or complex routing scenarios.
The insulation uses a PVC specially stabilized with chloride ions, formulated to resist aging and environmental stress. The external dimensions of 4.7 x 9.6 mm offer an optimal balance between robustness and handling. The 4mm² cross-section per conductor allows for the transmission of significant power without notable loss, even over long distances.
The distinctive blue sheath makes identification easy in multi-channel setups and adds an appealing aesthetic touch. This color is embedded in the material and does not fade over time, unlike superficial markings used on some competing cables.
The standout feature of the Classic 4 lies in its tin-plating technology, the result of extensive research by Jenving Technology’s engineers. Contrary to popular belief, tin does have a slightly higher electrical resistance than bare copper, but its benefits far outweigh this minor drawback.
Tin-plating effectively protects copper from long-term oxidation, a phenomenon that gradually degrades the performance of traditional cables. More importantly, this tin layer significantly reduces the skin effect—a physical phenomenon that pushes high frequencies toward the conductor’s surface and can dull treble reproduction. By minimizing these disruptive “jumps” of current between strand surfaces, tin-plating improves the temporal coherence of the musical signal.
This technical approach, validated by years of research in partnership with renowned Swedish universities, achieves performance close to much more expensive Litz cables, where each strand is individually shielded. Laboratory measurements confirm a significant reduction in parasitic inductance, a critical parameter for high-frequency reproduction.
The Classic 4 Blue excels particularly in high-power systems, where its generous cross-section prevents any limitation in energy transfer. Large floorstanding speakers, bi-amplified setups, and multi-channel home theater installations are its preferred domains. Its low inductance (0.55 µH/m) also makes it an excellent choice for long runs, where standard cables reach their limits.
For bi-wiring—the practice of separating the power supply to bass and mid/high drivers—the Classic 4 offers the necessary sonic coherence. Its particularly low resistance of 0.0043 Ω/m at 23°C ensures an excellent damping factor, allowing amplifiers to precisely control speaker diaphragms.
Home theater systems benefit from its flexibility for discreet routing and its robustness for permanent installations. The blue color coding makes it easy to identify in complex cable bundles, reducing the risk of errors during wiring or maintenance.
Manufacturing is carried out entirely in Sweden at Jenving Technology’s workshops, according to military-grade quality standards. Soldering personnel hold military-standard certifications, ensuring perfect reproducibility of assemblies. Each production batch is marked for complete traceability of materials and processes used.
The 5N OFC copper comes from suppliers selected for the consistency of their specifications. The tin-plating process, a critical point in manufacturing, is subject to strict control of temperature and duration parameters to achieve a uniform and adherent layer.
The PVC insulation uses a proprietary formulation resistant to UV, ozone, and temperature variations. Accelerated aging tests validate its durability over time, even in challenging environments.
Tin offers a neutral sonic character, unlike silver, which tends to artificially accentuate high frequencies. Gold, while an excellent conductor, is prohibitively expensive for use along the entire cable length. Tin provides the best compromise between oxidation protection, reduction of the skin effect, and sonic neutrality, while remaining economically viable.
Absolutely. Its homogeneous construction and low inductance make it an excellent choice for bi-wiring, where coherence between the cables feeding bass and mid/high drivers is crucial. The 4mm² cross-section is perfectly suited to demanding floorstanding speakers typically used in bi-wiring setups.
Thanks to its low resistance of 0.0043 Ω/m, the Classic 4 can be used over significant lengths. For 8-ohm speakers, lengths of 10 to 15 meters are perfectly acceptable. Beyond that, ensure the cable resistance does not exceed 5% of the speaker’s impedance to maintain a proper damping factor.
Silver cables offer slightly higher conductivity but often color the sound by accentuating high frequencies, which can lead to listening fatigue. The tinned Classic 4 prioritizes neutrality and tonal balance. Its value for money is also unmatched, as silver cables generally cost ten times more for equivalent performance.
No, the Classic 4 is a symmetrical cable that can be connected in either direction with no difference in performance. Unlike some directional cables on the market, its technical design does not favor any particular signal flow direction.
Absolutely. Its low inductance and stable construction make it an excellent choice for tube amplifiers, which are often more sensitive to load characteristics than transistor amplifiers. Its controlled resistance preserves the damping factor, which remains important even with modern tube amplifiers.
Based on reviews from customers who purchased this product, summarised by AI
Bruno
A cable that meets my expectations, but I haven't tried enough other cables to make a comparison..
Comment from 12 October 2026 — Experience from 1 October 2026
Thierry
Ideal and very economical for compensating for a small connection size (terminal block accepting no more than 4 mm²) on a JBL Synthesis 3 center channel.
Comment from 28 February 2026 — Experience from 8 July 2025
Kevin
Used on a new installation so no reference for comparison. The sound is good. No complaints.
Comment from 23 February 2026 — Experience from 12 February 2026
