{
  "version": "1.4",
  "lastUpdated": "2026-01-11",
  "tonearms": {
    "custom": {
      "id": "CUSTOM-001",
      "manufacturer": "Custom",
      "p2s": 215,
      "effLen": 233,
      "overhang": 18,
      "nativeOffsetAngle": null,
      "offsetAdjustable": true,
      "name": "Manual Entry",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "",
      "links": {}
    },
    "sme5": {
      "id": "SME-001",
      "manufacturer": "SME",
      "p2s": 215.35,
      "effLen": 233.15,
      "overhang": 17.8,
      "nativeOffsetAngle": 23.63,
      "offsetAdjustable": true,
      "name": "Series V",
      "type": "sliding_base",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "SME sliding base: Place stylus on null point, slide base until arm aligns with reference lines. Offset 23°38'.",
      "links": {
        "general": {
          "label": "Official Product Page",
          "url": "https://sme.co.uk/product/series-v/"
        },
        "manual": {
          "label": "Manuals & Downloads",
          "url": "https://sme.co.uk/audio/product/series-v"
        },
        "technical": {
          "label": "Stereophile Specifications",
          "url": "https://www.stereophile.com/content/sme-series-v-tonearm-specifications"
        }
      }
    },
    "sme309": {
      "id": "SME-002",
      "manufacturer": "SME",
      "p2s": 215.35,
      "effLen": 232.32,
      "overhang": 16.97,
      "nativeOffsetAngle": 23.2,
      "offsetAdjustable": true,
      "name": "309",
      "type": "sliding_base",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "SME sliding base: Place stylus on null point, slide base until arm aligns with reference lines.",
      "links": {
        "general": {
          "label": "HiFi-Wiki (DE)",
          "url": "https://www.hifi-wiki.de/index.php/SME_309"
        },
        "manual": {
          "label": "SME Manuals & Downloads",
          "url": "https://sme.co.uk/audio/product/series-v"
        },
        "technical": {
          "label": "Stereophile Analog Corner #245",
          "url": "https://www.stereophile.com/content/analog-corner-245-sme-model-15-turntable-sme-309-spd-tonearm"
        }
      }
    },
    "sme312": {
      "id": "SME-003",
      "manufacturer": "SME",
      "p2s": 293.7,
      "effLen": 309.0,
      "overhang": 15.3,
      "nativeOffsetAngle": 17.6,
      "offsetAdjustable": true,
      "name": "312S",
      "type": "sliding_base",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "SME sliding base: Place stylus on null point, slide base until arm aligns with reference lines",
      "links": {
        "general": {
          "label": "Vinyl Engine Library",
          "url": "https://www.vinylengine.com/library/sme/series-300.shtml"
        },
        "manual": {
          "label": "SME Manuals & Downloads",
          "url": "https://sme.co.uk/audio/product/series-v"
        }
      }
    },
    "sme3009": {
      "id": "SME-004",
      "manufacturer": "SME",
      "p2s": 215.7,
      "effLen": 231.56,
      "overhang": 15.86,
      "nativeOffsetAngle": 22.6,
      "offsetAdjustable": true,
      "name": "3009 Series II Improved",
      "type": "sliding_base",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Series II Improved version. Original Series II has different geometry (p2s=221.8, effLen=237.24).",
      "links": {
        "general": {
          "label": "HiFi-Wiki (DE)",
          "url": "https://www.hifi-wiki.de/index.php/SME_3009"
        },
        "technical": {
          "label": "Vinyl Engine Library",
          "url": "https://www.vinylengine.com/library/sme/3009.shtml"
        },
        "manual": {
          "label": "SME 3009 II Improved Manual (PDF)",
          "url": "https://sme.co.uk/wp-content/uploads/MODEL_3009_SERIES_II_IMPROVED_INSTRUCTION_BOOK.pdf"
        }
      }
    },
    "rega": {
      "id": "REGA-001",
      "manufacturer": "Rega",
      "p2s": 222,
      "effLen": 236.5,
      "overhang": 14.5,
      "nativeOffsetAngle": 21.55,
      "offsetAdjustable": false,
      "name": "RB220/330/880",
      "type": "stevenson_native",
      "recommendedAlign": "stevenson",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Fixed headshell geometry designed for Stevenson alignment. Mounting distance 222mm. Some audiophiles realign to Baerwald (requires 17.3mm overhang).",
      "links": {
        "general": {
          "label": "Official RB330 Page",
          "url": "https://www.rega.co.uk/products/rb330"
        },
        "manual": {
          "label": "RB330 User Manual (PDF)",
          "url": "https://www.rega.co.uk/download/rb330-retail-instructions-master-2017.pdf"
        },
        "technical": {
          "label": "All Rega Tonearms",
          "url": "https://www.rega.co.uk/products/tonearms"
        }
      }
    },
    "technics": {
      "id": "TECHNICS-001",
      "manufacturer": "Technics",
      "p2s": 215,
      "effLen": 230,
      "overhang": 15,
      "nativeOffsetAngle": 22.0,
      "offsetAdjustable": false,
      "name": "SL-1200",
      "type": "stevenson_native",
      "recommendedAlign": "stevenson",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Fixed headshell geometry designed for Stevenson. Factory alignment: Stylus 52mm from headshell back. Tracking error within 2°32' outer, 0°32' inner.",
      "links": {
        "general": {
          "label": "SL-1200 Heritage",
          "url": "https://www.technics.com/global/home/sl1200/features.html"
        },
        "manual": {
          "label": "SL-1200MK2 Service Manual",
          "url": "https://www.vinylengine.com/library/technics/sl-1200.shtml"
        },
        "technical": {
          "label": "HiFi-Wiki (DE)",
          "url": "https://www.hifi-wiki.de/index.php/Technics_SL-1200"
        }
      }
    },
    "project9": {
      "id": "PROJECT-001",
      "manufacturer": "Pro-Ject",
      "p2s": 212,
      "effLen": 230,
      "overhang": 18,
      "nativeOffsetAngle": 24.0,
      "offsetAdjustable": true,
      "name": "9cc EVO",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "9-inch carbon fiber tonearm. Effective mass: 8g. Detachable headshell.",
      "links": {
        "general": {
          "label": "Official EVO CC Page",
          "url": "https://www.project-audio.com/en/product/evo-cc-tonearms/"
        },
        "technical": {
          "label": "EVO Tonearm Range (PDF)",
          "url": "https://www.project-audio.com/wp-content/uploads/2023/09/EVO-Tonearm-Range-2023.pdf"
        }
      }
    },
    "project10": {
      "id": "PROJECT-002",
      "manufacturer": "Pro-Ject",
      "p2s": 238,
      "effLen": 254,
      "overhang": 16,
      "nativeOffsetAngle": 21.6,
      "offsetAdjustable": true,
      "name": "10cc EVO",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "10-inch carbon fiber tonearm. Effective mass: 8.5g. Detachable headshell.",
      "links": {
        "general": {
          "label": "Official EVO CC Page",
          "url": "https://www.project-audio.com/en/product/evo-cc-tonearms/"
        },
        "technical": {
          "label": "EVO Tonearm Range (PDF)",
          "url": "https://www.project-audio.com/wp-content/uploads/2023/09/EVO-Tonearm-Range-2023.pdf"
        }
      }
    },
    "linn": {
      "id": "LINN-001",
      "manufacturer": "Linn",
      "p2s": 211,
      "effLen": 229,
      "overhang": 18,
      "nativeOffsetAngle": 24.0,
      "offsetAdjustable": false,
      "name": "Ekos SE",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Effective mass: 11.5g. Machined titanium arm tube. Fixed (non-detachable) headshell - overhang adjustable but not headshell angle. Null points: 65.7mm/120.6mm (Baerwald).",
      "links": {
        "general": {
          "label": "Official Ekos SE Page",
          "url": "https://www.linn.co.uk/turntables/components/ekos-se"
        },
        "manual": {
          "label": "LinnDocs Specifications",
          "url": "https://docs.linn.co.uk/wiki/index.php/EKOS_SE"
        },
        "technical": {
          "label": "Stereophile Ekos SE Specifications",
          "url": "https://www.stereophile.com/content/linn-ekos-se-tonearm-keel-lp12-subchassis-trampolin-turntable-base-specifications"
        }
      }
    },
    "jelco250": {
      "id": "JELCO-001",
      "manufacturer": "Jelco",
      "p2s": 214,
      "effLen": 232,
      "overhang": 18,
      "nativeOffsetAngle": 23.8,
      "offsetAdjustable": true,
      "name": "TK-850S",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "Knife-edge bearing. Discontinued manufacturer. Detachable headshell.",
      "links": {
        "general": {
          "label": "Vinyl Engine Library",
          "url": "https://www.vinylengine.com/library/jelco/tk-850s.shtml"
        },
        "technical": {
          "label": "HomeTheaterHiFi Review",
          "url": "https://hometheaterhifi.com/reviews/vinyl/turntable-accessories/jelco-tk-850s-mkii-tonearm-review/"
        }
      }
    },
    "jelcoSA750L": {
      "id": "JELCO-002",
      "manufacturer": "Jelco",
      "p2s": 290,
      "effLen": 305,
      "overhang": 15,
      "nativeOffsetAngle": 19.0,
      "offsetAdjustable": true,
      "name": "SA-750L",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch gimbal bearing arm. Predecessor to TK-950L. Discontinued 2020.",
      "links": {
        "general": {
          "label": "Vinyl Engine Library",
          "url": "https://www.vinylengine.com/library/jelco.shtml"
        }
      }
    },
    "staxua7": {
      "id": "STAX-001",
      "manufacturer": "Stax",
      "p2s": 227,
      "effLen": 240,
      "overhang": 13,
      "nativeOffsetAngle": 20.0,
      "offsetAdjustable": true,
      "name": "UA-7",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "9-inch arm with replaceable arm tube. Effective mass: 16g. Vintage Japanese arm.",
      "links": {
        "general": {
          "label": "Vinyl Engine Manual",
          "url": "https://www.vinylengine.com/library/stax/ua-7.shtml"
        },
        "technical": {
          "label": "HiFi-Wiki Stax Tonarme",
          "url": "https://www.hifi-wiki.de/index.php/Stax_Tonarme"
        },
        "specs": {
          "label": "Japanese Arm Database",
          "url": "http://www7a.biglobe.ne.jp/~yosh/armdata.htm"
        }
      }
    },
    "staxua9": {
      "id": "STAX-002",
      "manufacturer": "Stax",
      "p2s": 230,
      "effLen": 247,
      "overhang": 17,
      "nativeOffsetAngle": 22.3,
      "offsetAdjustable": true,
      "name": "UA-9",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "9-inch arm with carbon fiber tapered tube option.",
      "links": {
        "general": {
          "label": "Vinyl Engine Manual",
          "url": "https://www.vinylengine.com/library/stax/ua-9.shtml"
        },
        "technical": {
          "label": "HiFi-Wiki Stax Tonarme",
          "url": "https://www.hifi-wiki.de/index.php/Stax_Tonarme"
        }
      }
    },
    "staxua70": {
      "id": "STAX-003",
      "manufacturer": "Stax",
      "p2s": 300,
      "effLen": 312,
      "overhang": 12,
      "nativeOffsetAngle": 17.0,
      "offsetAdjustable": true,
      "name": "UA-70",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch arm with replaceable arm tube. Dual suspension bearing.",
      "links": {
        "general": {
          "label": "Vinyl Engine Manual",
          "url": "https://www.vinylengine.com/library/stax/ua-70.shtml"
        },
        "technical": {
          "label": "HiFi-Wiki Stax Tonarme",
          "url": "https://www.hifi-wiki.de/index.php/Stax_Tonarme"
        },
        "specs": {
          "label": "Japanese Arm Database",
          "url": "http://www7a.biglobe.ne.jp/~yosh/armdata.htm"
        }
      }
    },
    "grahamPhantom": {
      "id": "GRAHAM-001",
      "manufacturer": "Graham",
      "p2s": 217.4,
      "effLen": 235,
      "overhang": 17.6,
      "nativeOffsetAngle": 23.43,
      "offsetAdjustable": true,
      "name": "Phantom Elite/III (9\")",
      "type": "unipivot",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Unipivot with Magneglide magnetic stabilization. Effective mass: 11.5g.",
      "links": {
        "general": {
          "label": "Graham Engineering Official",
          "url": "https://www.graham-engineering.com/products/tonearms/graham-engineering-phantom-3.php"
        },
        "technical": {
          "label": "TAS Review",
          "url": "https://www.theabsolutesound.com/articles/graham-engineering-phantom-iii-tonearm/"
        },
        "specs": {
          "label": "Artisan Fidelity Specs",
          "url": "https://www.artisanfidelity.com/tonearms/graham-phantom-b44-supreme"
        }
      }
    },
    "grahamPhantom12": {
      "id": "GRAHAM-002",
      "manufacturer": "Graham",
      "p2s": 295.6,
      "effLen": 308.8,
      "overhang": 13.2,
      "nativeOffsetAngle": 17.5,
      "offsetAdjustable": true,
      "name": "Phantom Elite/III (12\")",
      "type": "unipivot",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch unipivot with Magneglide magnetic stabilization. Effective mass: 14g.",
      "links": {
        "general": {
          "label": "Graham Engineering Official",
          "url": "https://www.graham-engineering.com/products/tonearms/graham-engineering-phantom-elite.php"
        },
        "technical": {
          "label": "Elusive Disc",
          "url": "https://elusivedisc.com/graham-engineering-phantom-elite-12-tonearm-sme-fixed-mount/"
        }
      }
    },
    "sonyPUA7": {
      "id": "SONY-001",
      "manufacturer": "Sony",
      "p2s": 215,
      "effLen": 232,
      "overhang": 17,
      "nativeOffsetAngle": 23.0,
      "offsetAdjustable": true,
      "name": "PUA-7",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "Biotracer servo tonearm. Dynamic damping system.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/sony/pua-7.shtml"
        }
      }
    },
    "sonyPUA9": {
      "id": "SONY-002",
      "manufacturer": "Sony",
      "p2s": 230,
      "effLen": 246,
      "overhang": 16,
      "nativeOffsetAngle": 21.8,
      "offsetAdjustable": true,
      "name": "PUA-9",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "Biotracer dynamic balance tonearm with servo control.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/sony/pua-9.shtml"
        }
      }
    },
    "smeSeriesIV": {
      "id": "SME-005",
      "manufacturer": "SME",
      "p2s": 215.35,
      "effLen": 233.15,
      "overhang": 17.8,
      "nativeOffsetAngle": 23.63,
      "offsetAdjustable": true,
      "name": "Series IV",
      "type": "sliding_base",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "Same geometry as Series V but ABEC 3 bearings, copper wiring, no fluid damping. 1987-present.",
      "links": {
        "general": {
          "label": "SME Official",
          "url": "https://sme.co.uk/product/series-iv/"
        }
      }
    },
    "smeSeriesV12": {
      "id": "SME-006",
      "manufacturer": "SME",
      "p2s": 295.6,
      "effLen": 308.8,
      "overhang": 13.2,
      "nativeOffsetAngle": 17.62,
      "offsetAdjustable": true,
      "name": "Series V-12",
      "type": "sliding_base",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "12-inch version of Series V. 27% reduction in tracking error vs 9-inch arms.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/sme/series-v.shtml"
        }
      }
    },
    "smeM2_9": {
      "id": "SME-007",
      "manufacturer": "SME",
      "p2s": 215.4,
      "effLen": 233.2,
      "overhang": 17.8,
      "nativeOffsetAngle": 23.63,
      "offsetAdjustable": true,
      "name": "M2-9",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "Entry-level SME. 9.5g effective mass. Detachable magnesium headshell with azimuth adjustment.",
      "links": {
        "general": {
          "label": "SME Official",
          "url": "https://sme.co.uk/product/m2-9-tonearm/"
        }
      }
    },
    "smeM2_12": {
      "id": "SME-008",
      "manufacturer": "SME",
      "p2s": 295.6,
      "effLen": 308.8,
      "overhang": 13.21,
      "nativeOffsetAngle": 17.62,
      "offsetAdjustable": true,
      "name": "M2-12",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "12-inch M2 series. Stainless steel arm tube. Detachable magnesium headshell.",
      "links": {
        "general": {
          "label": "SME Official",
          "url": "https://sme.co.uk/product/m2-12-tonearm/"
        }
      }
    },
    "sme3009SeriesIII": {
      "id": "SME-009",
      "manufacturer": "SME",
      "p2s": 215.4,
      "effLen": 228.6,
      "overhang": 13.2,
      "nativeOffsetAngle": 23.5,
      "offsetAdjustable": true,
      "name": "3009 Series III",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Ultra-low mass (5g) design with titanium arm tube. For high-compliance cartridges. 1978-1983. Multiple arm tube variants exist.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/sme/3009-series-3.shtml"
        },
        "technical": {
          "label": "Lenco Heaven Forum",
          "url": "https://www.lencoheaven.net/forum/index.php?topic=27589.0"
        }
      }
    },
    "sme3012R": {
      "id": "SME-010",
      "manufacturer": "SME",
      "p2s": 295.6,
      "effLen": 308.8,
      "overhang": 13.2,
      "nativeOffsetAngle": 17.6,
      "offsetAdjustable": true,
      "name": "3012-R",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "12-inch knife-edge bearing. Steel arm tube. Japanese market revival 1981-2008.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/sme/3012.shtml"
        }
      }
    },
    "ortofonAS212S": {
      "id": "ORTOFON-001",
      "manufacturer": "Ortofon",
      "p2s": 216.0,
      "effLen": 231.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 22.0,
      "offsetAdjustable": true,
      "name": "AS-212S (Jelco)",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Jelco-made version (2000s). Uses Japanese geometry (null points 58.5mm/114.5mm). Original 1970s Danish AS-212 has different specs.",
      "links": {
        "general": {
          "label": "Ortofon AS-212S Official",
          "url": "https://ortofon.com/pages/as-212s-9"
        },
        "technical": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/ortofon/as-212.shtml"
        }
      }
    },
    "ortofonRS212D": {
      "id": "ORTOFON-002",
      "manufacturer": "Ortofon",
      "p2s": 216.0,
      "effLen": 231.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 22.0,
      "offsetAdjustable": true,
      "name": "RS-212D",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Jelco-made reference arm. Uses Japanese geometry (null points 58.5mm/114.5mm). Improved bearings over AS-212S.",
      "links": {
        "general": {
          "label": "Ortofon RS-212D Official",
          "url": "https://ortofon.com/pages/rs-212d-9"
        },
        "technical": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/ortofon/rs-212d.shtml"
        }
      }
    },
    "ortofonRS309D": {
      "id": "ORTOFON-003",
      "manufacturer": "Ortofon",
      "p2s": 314.0,
      "effLen": 329.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 19.0,
      "offsetAdjustable": true,
      "name": "RS-309D",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch Jelco-made arm. Note: '309' is model number, NOT effective length. Actual effLen is 329mm. Uses Japanese geometry.",
      "links": {
        "general": {
          "label": "Ortofon RS-309D Official",
          "url": "https://ortofon.com/pages/rs-309d-12"
        },
        "technical": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/ortofon/rs-309d.shtml"
        }
      }
    },
    "graceG707": {
      "id": "GRACE-001",
      "manufacturer": "Grace",
      "p2s": 222.0,
      "effLen": 237.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 21.0,
      "offsetAdjustable": true,
      "name": "G-707",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Classic 9-inch arm. Low mass (5g) for high compliance cartridges. Very popular in 1970s-80s. All Grace arms share same geometry.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/grace/g-707.shtml"
        }
      }
    },
    "graceG714": {
      "id": "GRACE-002",
      "manufacturer": "Grace",
      "p2s": 222.0,
      "effLen": 237.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 21.0,
      "offsetAdjustable": true,
      "name": "G-714",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Improved version of G-707 with better bearings. Fixed headshell option available.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/grace/g-714.shtml"
        }
      }
    },
    "graceG840": {
      "id": "GRACE-003",
      "manufacturer": "Grace",
      "p2s": 222.0,
      "effLen": 237.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 21.0,
      "offsetAdjustable": true,
      "name": "G-840F",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Higher mass variant (12g) for low compliance MC cartridges. Same geometry as G-707/G-714.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/grace/g-840.shtml"
        },
        "manual": {
          "label": "G-840F Manual (PDF)",
          "url": "https://www.vinylengine.com/library/grace/g-840f.shtml"
        }
      }
    },
    "thorensTP16": {
      "id": "THORENS-001",
      "manufacturer": "Thorens",
      "p2s": 215.6,
      "effLen": 232.0,
      "overhang": 16.4,
      "nativeOffsetAngle": 23.0,
      "offsetAdjustable": false,
      "name": "TP-16 Mk IV",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Fitted to TD-160 Mk IV, TD-320, TD-520, Ambiance. Proprietary TP-68 headshell. Earlier Mk I-III have different specs (effLen=230, overhang=14.4).",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/thorens/tp-16.shtml"
        },
        "technical": {
          "label": "The Analog Dept Thorens Chart",
          "url": "https://www.theanalogdept.com/thorens_tonearms.htm/"
        }
      }
    },
    "thorensTP90": {
      "id": "THORENS-002",
      "manufacturer": "Thorens",
      "p2s": 215.0,
      "effLen": 232.8,
      "overhang": 17.8,
      "nativeOffsetAngle": 23.6,
      "offsetAdjustable": true,
      "name": "TP-90",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "High-end Thorens arm. Fitted to TD-320, TD-520. TP-95 headshell with azimuth adjustment.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/thorens/tp-90.shtml"
        },
        "technical": {
          "label": "The Analog Dept Thorens Chart",
          "url": "https://www.theanalogdept.com/thorens_tonearms.htm/"
        }
      }
    },
    "fr64S": {
      "id": "FR-001",
      "manufacturer": "Fidelity Research",
      "p2s": 230.0,
      "effLen": 245.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 21.5,
      "offsetAdjustable": true,
      "name": "FR-64S",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Legendary high-mass (35g) arm for low compliance MC cartridges. Highly sought after.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/fidelity-research/fr-64.shtml"
        },
        "technical": {
          "label": "Audio-Database Specifications",
          "url": "https://audio-database.com/FIDELITYRESEARCH/etc/fr-64s.html"
        }
      }
    },
    "fr66S": {
      "id": "FR-002",
      "manufacturer": "Fidelity Research",
      "p2s": 295.0,
      "effLen": 307.0,
      "overhang": 12.0,
      "nativeOffsetAngle": 16.8,
      "offsetAdjustable": true,
      "name": "FR-66S",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch version of FR-64. Arguably the most desirable vintage tonearm. Japanese Stevenson-style geometry.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/fidelity-research/fr-66.shtml"
        },
        "technical": {
          "label": "Audio-Database Specifications",
          "url": "https://audio-database.com/FIDELITYRESEARCH/etc/fr-66s.html"
        }
      }
    },
    "denonDA307": {
      "id": "DENON-001",
      "manufacturer": "Denon",
      "p2s": 230.0,
      "effLen": 244.0,
      "overhang": 14.0,
      "nativeOffsetAngle": 20.7,
      "offsetAdjustable": true,
      "name": "DA-307",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Classic Denon 9.6-inch arm for DL-103. Medium mass (12g). S-shaped detachable headshell. Same geometry as DA-309.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/denon/da-307.shtml"
        },
        "technical": {
          "label": "Audio-Database Specifications",
          "url": "https://audio-database.com/DENON-COLUMBIA/etc/da-307.html"
        }
      }
    },
    "denonDA309": {
      "id": "DENON-002",
      "manufacturer": "Denon",
      "p2s": 230.0,
      "effLen": 244.0,
      "overhang": 14.0,
      "nativeOffsetAngle": 20.7,
      "offsetAdjustable": true,
      "name": "DA-309",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Higher-end Denon arm. Same geometry as DA-307 but with improved bearings and wider cartridge range (5-25g vs 5-10g).",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/denon/da-309.shtml"
        },
        "technical": {
          "label": "Vintage Audio Heritage",
          "url": "https://vintage-audio-heritage.fr/viewtopic.php?t=178"
        }
      }
    },
    "emt929": {
      "id": "EMT-001",
      "manufacturer": "EMT",
      "p2s": 230.0,
      "effLen": 244.0,
      "overhang": 14.0,
      "nativeOffsetAngle": 20.83,
      "offsetAdjustable": true,
      "name": "929",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Professional broadcast tonearm. 9-inch. Designed for EMT TSD cartridges. Null points: 57mm/117mm.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/emt/929.shtml"
        },
        "technical": {
          "label": "Stereophile Listening #67",
          "url": "https://www.stereophile.com/artdudleylistening/708listen/index.html"
        },
        "specs": {
          "label": "Fabtech EMT Tonearms",
          "url": "https://www.fabtech.de/en_emt_tone-arms.html"
        }
      }
    },
    "emt997": {
      "id": "EMT-002",
      "manufacturer": "EMT",
      "p2s": 297.0,
      "effLen": 307.0,
      "overhang": 10.0,
      "nativeOffsetAngle": 17.5,
      "offsetAdjustable": true,
      "name": "997",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch professional broadcast arm. Designed to replace Ortofon RF-297, uses same 297mm mounting distance. Studio reference.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/emt/997.shtml"
        },
        "technical": {
          "label": "Audio-Database",
          "url": "https://audio-database.com/BARCO/etc/997.html"
        },
        "specs": {
          "label": "Fabtech EMT Tonearms",
          "url": "https://www.fabtech.de/en_emt_tone-arms.html"
        }
      }
    },
    "koetsuSA1100D": {
      "id": "KOETSU-001",
      "manufacturer": "Koetsu",
      "p2s": 292.0,
      "effLen": 310.0,
      "overhang": 18.0,
      "nativeOffsetAngle": 18.0,
      "offsetAdjustable": true,
      "name": "SA-1100D",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "12-inch knife-edge bearing arm. Made by Jelco. Optimized for Koetsu cartridges.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/koetsu/sa-1100d.shtml"
        }
      }
    },
    "schroderCB": {
      "id": "SCHRODER-001",
      "manufacturer": "Schröder",
      "p2s": 222.0,
      "effLen": 239.3,
      "overhang": 14.52,
      "nativeOffsetAngle": 23.0,
      "offsetAdjustable": true,
      "name": "CB",
      "type": "unipivot",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Entry-level Schröder. Unique magnetic bearing design. 9.5-inch effective length.",
      "links": {
        "general": {
          "label": "Schröder Official",
          "url": "https://www.frank-schroder.de/"
        },
        "technical": {
          "label": "Dohmann Audio Specs",
          "url": "https://dohmannaudio.com/schroder-cb-tonearm/"
        },
        "specs": {
          "label": "OMA Specs",
          "url": "https://oswaldsmillaudio.com/cb"
        }
      }
    },
    "schroderRef": {
      "id": "SCHRODER-002",
      "manufacturer": "Schröder",
      "p2s": 222.0,
      "effLen": 239.3,
      "overhang": 14.52,
      "nativeOffsetAngle": 23.0,
      "offsetAdjustable": true,
      "name": "Reference",
      "type": "unipivot",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Flagship Schröder arm. Ebony arm wand. Magnetic bearing with viscous damping. BESPOKE: specs may vary per order.",
      "links": {
        "general": {
          "label": "Schröder Official",
          "url": "https://www.frank-schroder.de/"
        },
        "technical": {
          "label": "Artisan Fidelity",
          "url": "https://www.artisanfidelity.com/tonearms/schroeder-reference-sq"
        }
      }
    },
    "bauerDPS": {
      "id": "BAUER-001",
      "manufacturer": "Bauer Audio",
      "p2s": 222.0,
      "effLen": 239.0,
      "overhang": 17.0,
      "nativeOffsetAngle": 23.0,
      "offsetAdjustable": true,
      "name": "DPS Tonearm",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": null,
      "note": "Designed for Bauer DPS turntable. Premium German engineering.",
      "links": {
        "general": {
          "label": "Bauer Audio",
          "url": "https://www.baueraudio.de/"
        }
      }
    },
    "jelcoSA750D": {
      "id": "JELCO-003",
      "manufacturer": "Jelco",
      "p2s": 214.0,
      "effLen": 229.0,
      "overhang": 15.0,
      "nativeOffsetAngle": 22.0,
      "offsetAdjustable": true,
      "name": "SA-750D (original)",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "Original version with Japanese geometry. Later SA-750DB has different specs (effLen=228, overhang=18, offset=23.75). TK-850S replaced this with Baerwald geometry.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/jelco/sa-750d.shtml"
        }
      }
    },
    "jelcoTK950L": {
      "id": "JELCO-004",
      "manufacturer": "Jelco",
      "p2s": 290.0,
      "effLen": 303.0,
      "overhang": 13.0,
      "nativeOffsetAngle": 17.7,
      "offsetAdjustable": true,
      "name": "TK-950L",
      "type": "standard",
      "recommendedAlign": "loefgren_a",
      "curated": false,
      "auditorName": "Audit 2026-01",
      "note": "12-inch dynamic balance knife-edge arm. For low compliance cartridges. Discontinued 2020.",
      "links": {
        "general": {
          "label": "Vinyl Engine",
          "url": "https://www.vinylengine.com/library/jelco/tk-950.shtml"
        },
        "technical": {
          "label": "Respectphono Specs",
          "url": "https://respectphono.de/en/jelco-tk-950-l-12-tonearm.html"
        }
      }
    }
  },
  "alignments": {
    "loefgren_a": {
      "inner": 66.0,
      "outer": 120.9,
      "name": "Löfgren A / Baerwald",
      "desc": "Equal distortion at inner, middle, and outer grooves"
    },
    "loefgren_b": {
      "inner": 70.3,
      "outer": 116.6,
      "name": "Löfgren B",
      "desc": "Minimizes average (RMS) distortion across entire record"
    },
    "stevenson": {
      "inner": 60.325,
      "outer": 117.42,
      "name": "Stevenson",
      "desc": "Minimizes distortion at inner grooves (good for 45s)"
    }
  }
}