Audiogon forum discussion - live-sound/helix GitHub Wiki

This document summarizes practical information shared in the Audiogon forum thread regarding the DIY Helix Geometry cable design, initially focusing on converting Duelund cables but expanding to various builds. The design originates from user williewonka. Note: williewonka's original website image99.net is down due to cost, but PDF build instructions are now available via links in this new thread: https://forum.audiogon.com/discussions/diy-helix-geometry-cabling

Summary is done by Google Gemini 2.5 Pro

Core Concept (Original Conversion by @wig):

  • Starting Point: Duelund interconnect with KLE connectors.
  • Modification:
    • Replaced the Duelund neutral wire with Mil-Spec 16 AWG silver-plated copper wire.
    • The new neutral wire is 3 times longer than the signal wire.
    • The neutral wire is coiled around the signal wire (Helix Geometry).
    • The Duelund signal wire was retained (implied).
  • Initial Results (Zero Burn-in): Sound stage became much wider/deeper, much tighter/focused image, clarity/transparency like nothing heard before regardless of cost. Outperformed a commercial Helix cable loom. (@wig)
  • Burn-in: Requires 200+ hours (ICs up to 250-400h, SCs ~200h, PCs ~100h) to fully settle. Can sound rough around 15-20 hours.

General Sonic Characteristics Reported by Users:

  • Wider, deeper, higher soundstage.
  • Tighter, more focused image, precise instrument/artist placement, better separation.
  • Improved clarity, transparency, detail retrieval (low-level details, venue acoustics, subtle nuances, decay, air, texture).
  • More dynamic, punchy, faster transients, better realism.
  • Natural, organic presentation, less glare, less "digital" sound, more "musical".
  • Quiet background, lower noise floor.
  • Full-bodied sound, improved texture, warmth (depending on wire choice).
  • Makes poor recordings more listenable (@lemonhaze).
  • System improvements are cumulative as more Helix cables are added.
  • Reported as significant upgrades, sometimes surpassing expectations for component upgrades (@toolbox149: "holy crap").
  • Compared favorably to expensive commercial cables (@wig, @lemonhaze vs Gryphon).

Recommended Materials & Build Variations:

Signal / Live Conductors:

  • Preferred Wires (Generally Copper OCC or Silver Variants):
    • Neotech UP-OCC Solid Copper (Teflon or PVC insulation): Often cited as top performer, especially when insulation is removed ("Air" version). Provides warmth, big stage, dynamics. Widely used and recommended. (@williewonka, @grannyring). Made by Wan Lung, Taiwan (only current licensed OCC factory).
    • VH Audio Solid UP-OCC Copper (AirLok insulation): Very close performance to Neotech, sometimes described as slightly more airy/detailed but potentially more forward than Neotech (@grannyring prefers Neotech warmth). Airlok Dk < 1.45. May not be true licensed OCC per @camrector, but performs well.
    • VH Audio Solid UP-OCC Silver (AirLok insulation): Considered top-tier for resolution and realism, but significantly more expensive. Some find all-silver too much, best used selectively (e.g., digital source cables, IC signal). (@grannyring, @williewonka).
    • Parts Connexion Bare Solid UP-OCC Copper (6N): Excellent performer, potentially slightly better than stripped Neotech 5N OCC (@williewonka). Ideal for Air Helix builds. Availability of gauges >18AWG is now limited. May not be true licensed OCC per @camrector.
    • Parts Connexion Bare Solid UP-OCC Silver (5N): Top choice for IC signal wires for ultimate detail/dynamics (@williewonka).
    • Mundorf Solid Silver/Gold (1% Gold): Good, but generally considered slightly less performant (dynamics/details) or different flavor than the top OCC coppers/silvers in this geometry. More relaxed sound. (@williewonka).
    • Duelund Tinned Copper (Cotton/Oil or Polycast): The starting point. Good, but generally outperformed by OCC copper/silver options in Helix geometry for resolution/dynamics. Can be warmer, more relaxed (good for system tuning). (@grannyring, @aniwolfe). Duelund PVC PC reported better than Neotech UPOCC PC for DAC (@norco74).
    • PC Triple C Solid Core Copper (e.g., Acoustic Revive SPC-AV 0.9mm/19AWG): Highly recommended by @pindac as alternative/superior to OCC, offering clarity, balance, substance, realism. Used successfully in Helix build by @mbolek (better than his OCC build). Needs burn-in.
    • D.U.C.C. (Mitsubishi): Praised by @pindac, especially for digital source links (separation, soundstage, richness). Used in Acrolink, Audio Technica, Luxman.
    • Jupiter Wire (Copper/Silver, Cotton insulation): Recommended by @mitch2, @grannyring for general quality/musicality, but not specifically tested in Helix builds by them. @mitch2 used 8x28AWG 6N Cu/Cotton for braided ICs successfully.
  • Gauge:
    • ICs: Typically 2 runs of 18 AWG or 20 AWG per conductor (Double Barrel/Shotgun). @toolbox149 found 18+20 AWG best balance vs 18+18 or 18+24. @lemonhaze found 2x24AWG Ag slightly light, improved by adding 20AWG Ag (~17.5AWG total).
    • Speaker Cables: Often 2 runs of 16 AWG or 14 AWG (effective 13 / 11 AWG) for signal. Gauge depends on amp power/speaker impedance/frequency range. 2x18AWG (15AWG effective) likely sufficient for tweeters (@williewonka).
    • Power Cords (Live): Commonly 2 runs of 16 AWG (Source) or 2 runs of 14 AWG (Amps/Conditioners) Neotech/VH Audio OCC Copper. Some use multiple runs of 18 AWG (e.g., @tecknik uses 8x18AWG). @grannyring prefers 2x12ga Neotech for high current.
  • "Air Helix" (Bare Wire in Tube): Stripping insulation from signal/live wire and inserting into a larger Teflon/PVC tube provides significant sonic gains (clarity, dynamics, imaging).
    • Teflon tube ID should be ~25-30% larger than bare wire OD (@williewonka). Larger tube doesn't improve sound, might collapse. Wall thickness (0.5mm vs 1.0mm) likely insignificant (@williewonka). Vinyl tube usable, @toolbox149 found no sonic difference vs PTFE, others prefer PTFE (@tecknik).
    • Requires sealing tube ends (adhesive heat shrink, hot glue, epoxy, silicone grease + heatshrink (@lemonhaze), wool+shellac) to minimize oxidation.
    • Bare UP-OCC copper seems resistant to detrimental oxidation inside sealed tube over months (@williewonka). Silver less of a concern. Deoxit wipe before insertion possible (@norco74). Gloves recommended when handling bare wire.
  • Double Barrel / Double Shotgun (@grannyring's contribution): Using two runs of the chosen signal wire (often twisted together) consistently reported as superior to single run (more scale, dynamics, ease, presence).
  • Multiple Gauges (Varistrand): @lemonhaze considered mixing 26+22+18 AWG Ag based on Kimber, but no reports of success/failure in Helix geometry. @williewonka advises against mixing Cu/Ag parallel due to speed differences.

Neutral / Return Conductors (Helix Coil):

  • Preferred Wire: Silver-plated Copper Mil-Spec stranded wire (Teflon insulation) is the established recommendation for optimal balance of performance, flexibility, and ability to hold the coil shape. (@williewonka, @grannyring)
    • Gauge: 16 AWG for ICs, 12 AWG or 10 AWG for PCs and SCs (often doubled, e.g., 2x12 AWG for PCs/SCs, 2x16 AWG for Double Double ICs). Must be larger gauge than signal conductor(s) (@williewonka).
    • Source: Take Five Audio (TFA) Canada (Cryo'd, high quality, slow shipping). Apex Jr (US). Performance PCs (US). Jantzen Audio (Europe). Other surplus/Mil-spec suppliers.
  • Alternative: Replacing Mil-Spec neutral with Neotech UP-OCC Copper (Solid or Stranded, Teflon insulated) reported as significant upgrade (@wig, @williewonka). Single run UP-OCC often sufficient vs double Mil-Spec.
    • Solid core harder to coil than stranded Mil-Spec. Stranded UP-OCC easier than solid UP-OCC.
    • Using bare UP-OCC in Teflon tube for neutral helix: Possible but difficult to wind without wire creeping in tube (@williewonka). Not found beneficial vs insulated UP-OCC neutral (@williewonka).
  • PC Triple C / D.U.C.C.: @mbolek used Neotech OCC copper for ground helix on CCC XLR IC. Performance of CCC/DUCC as neutral not explicitly reported in Helix.
  • Coiling: Wound tightly around a rod (e.g., 5/16" or ~8mm fiberglass for IC/PC, larger like 3/8"-1/2" for SC). Direction typically Counter-Clockwise (CCW) when viewed winding around the signal wire. Tighter/looser twist of coil itself doesn't seem to impact sound (@williewonka).
  • Ratio: Length of neutral wire is typically 3 times the length of the signal wire (3:1 ratio) for ICs/PCs. 4:1 or higher sometimes used for phono ICs. 2.5:1 generally sufficient for SCs (@williewonka).
  • Double Helix Neutral: Using two runs of the neutral wire (coiled side-by-side) reported slightly better for ICs ("Double Double"). Diminishing returns noted by @williewonka, single UP-OCC neutral often preferred for cost/effort.

Ground Wire (PCs):

  • Typically 1 run of 12 AWG copper wire (e.g., hardware store, Teflon insulated best) or Mil-Spec wire. Some use 2 runs.
  • Safety regulations (e.g., Europe) may require Ground >= Live/Neutral gauge (@mawe). @williewonka believes Helix ground sizes (12ga/14ga) are sufficient for protection in typical NA scenarios, but advises caution and suggests using same gauge for all three if concerned.

Connectors:

  • RCA Plugs:
    • KLEI Harmony Plugs: Still highly recommended (Absolute, Copper, Silver, Classic). Low mass/contact area, unique impedance beneficial for SPDIF at any length. Need good soldering technique. Availability might be decreasing (@lemonhaze).
    • WBT NextGen (Low Eddy): Recommended by @pindac as superior to KLEI based on friend's experience with PC Triple C cables (improved "envelope").
    • AECO: Offer pure silver option (@wyan001).
    • Zavfino 1877: OCC Copper option (@pindac).
    • Furutech / Vampire: Other options mentioned.
  • XLR Plugs:
    • AECO: Copper/Silver used by @mbolek, liked. Low mass, hollow tubes (@camrector).
    • ETI Kryo: Silver recommended for resolution (@mawe).
    • Atlas: OCC copper pins, some silver plated (@pindac, @williewonka).
    • Viborg: Rhodium plated pure copper (@pindac).
    • DH Labs / Vampire: Pure copper, good value, look identical (@grannyring).
    • Neutrik (Silver Plated): Best price/performance (@mawe), widely used, reliable.
    • Wiring: Standard Helix XLR: Pin 1=Ground (Helix Coil), Pin 2=Signal (+), Pin 3=Signal (-). Double Shotgun Helix XLR (@grannyring): Pin 1=Double Helix Ground Coil (2x16ga Mil-spec), Pin 2=Signal Wire 1 (+), Pin 3=Signal Wire 2 (-). For balanced PC: Use identical L/N conductors, ground wire is Helix Coil (@williewonka).
  • Power Plugs (IEC/Mains):
    • SonarQuest: Silver Plated Copper (clear/colored body) good value, detailed/dynamic (@williewonka). Gold Plated warmer. Carbon Fiber barrels available separately (@williewonka).
    • ieGO 8075 Rhodium: Used by @stofarius.
    • Furutech: NCF series used (@t_ramey, @tecknik). FI-15(G) IEC good (@mawe). High quality but potentially "overbuilt" for audio (@williewonka).
    • Viborg / Vanguard: Good value options (@williewonka).
  • Speaker Connectors (Bananas/Spades):
    • KLEI Harmony Bananas: Good, but potential compatibility issues (too short/loose) with some amps (Bryston) (@norco74, @williewonka).
    • Furez: Various sizes, copper or silver plated, good for larger gauge.
    • ETI Pure Copper Spades: Recommended for heavy gauge wire, sound quality (@mawe).
    • Neutrik Speakons: Surprisingly preferred over AECO/KLE/ETI by @camrector. Low mass?
    • Generic Gold Plated Beryllium Copper: Used by @norco74 after KLEI issues.

Build Tips & Considerations:

  • Soldering: Quality solder (WBT 4%, Cardas Eutectic, Mundorf S/G). Hot iron, quick application. Tin wires. Use jig. @ketchup's pointed-wire-in-V method for KLEI tabs.
  • Helix Winding: Use appropriate rod diameter (5/16" IC/PC, 3/8"-1/2" SC). Fiberglass rod preferred. Coiling multiple wires side-by-side possible. Cut tube longer than bare wire for Air Helix coils (@williewonka).
  • Air Helix Assembly: Careful stripping. Insert wire (floss+weight trick?). Seal ends (adhesive heat shrink, hot glue, epoxy, silicone grease + heatshrink).
  • Damping: Cotton sleeve over signal wire/tube can improve musicality/tame vibrations (@grannyring).
  • Outer Sleeve: Optional. Nylon expandable good for looks/flexibility, doesn't degrade sound, hides "lumps" (@williewonka, @norco74). Silk also used (@camrector).
  • Directionality: Less critical with Helix. Follow wire markings if desired, keep consistent.
  • Break-in: Essential. Can sound rough initially (15-50h), then improve significantly over 100-400+ hours depending on cable type/materials. Solder joints also need time (~50h). Cables may need time to settle again after being moved/reseated (24h).

Compatibility Issues (Important Caveats):

  • Balanced Output Amplifiers: Standard (asymmetrical neutral) Helix Speaker Cables are NOT recommended. Requires symmetrical speaker cables (identical +/- conductors kept separate). See @williewonka's site/posts for incompatible amp list and alternative balanced build geometry.
  • Balanced Power Supplies: Standard (asymmetrical neutral) Helix Power Cables are NOT recommended. Use symmetrical PCs (identical L/N conductors). @sns had success with VH Airlok L / Mil-Spec N into BPT conditioner, but switching to symmetrical build advised.
  • Tube Amp Hum: Rare reports (@willgolf, @jambaj0e), usually traced to faulty tubes exacerbated by the revealing nature of Helix cables, not the cables themselves.

Other Cable Types:

  • SPDIF (Digital Coax): Helix IC build (RCA or BNC) works exceptionally well. Length not critical with KLEI plugs. UP-OCC Silver signal + UP-OCC Copper neutral recommended for ultimate performance. (@williewonka, @wig).
  • USB: Helix USB possible (see @grannyring design / @williewonka link). Gauge limitations for connectors.
  • Ethernet: Helix geometry likely offers no benefit (@williewonka).
  • Headphone: Standard Helix unsuitable for balanced headphones (@williewonka).
  • DC Power Cables: Helix geometry works well (@tecknik). 4:1 neutral ratio suggested (@williewonka).

Other Notes:

  • This summary reflects collective experiences within this thread. YMMV.
  • Experimentation encouraged, but start with established recipes.
  • Build/test one cable type at a time.
  • Consider iFi AC Purifier for subtle final noise reduction if no other power conditioning used (@williewonka).