{
  "format": "circuit-codex-reference",
  "version": 1,
  "id": "5e1",
  "url": "https://circuitcodex.com/amps/5e1/",
  "attribution": "The Analog Maker / Circuit Codex",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "revision": "ebddc3fd2cf887dca010bbe60487d7391ea6c052",
  "scope": "DC and drawing checks have separate coverage. See included check results and the circuit page; not a dimensioned build template or a physical-build certification.",
  "metadata": {
    "id": "5e1",
    "name_style": "Tweed Champ-style",
    "family": "tweed",
    "era": {
      "start": 1955,
      "end": 1957
    },
    "wattage": 5,
    "tubes": [
      "12AX7",
      "6V6GT",
      "5Y3GT"
    ],
    "topology": {
      "rectifier": {
        "kind": "tube",
        "type": "5Y3GT"
      },
      "bias": "cathode",
      "phase_inverter": "none",
      "tone_stack": "none"
    },
    "lineage": {
      "derived_from": [
        "5c1"
      ],
      "influenced": [
        "5f1"
      ]
    },
    "conventions": {
      "designators": "sequential"
    },
    "sources": [
      {
        "desc": "Fender 'Champ-Amp' Model 5E1 drawing (H-EE): layout, schematic, and the printed voltage chart all read directly from the published sheet (2026-07-18) — component values, the choke-first B+ chain (reservoir +320 -> choke -> +305 -> 22k -> +260), the 6V6 plate+screen sharing the post-choke node, and the 22k negative feedback into the second 12AX7 cathode. The drawing prints no transformer or choke part numbers. Not reproduced here; archived at EL34World",
        "url": "https://el34world.com/charts/Schematics/files/Fender/Fender_champ_5e1.pdf"
      },
      {
        "desc": "ampbooks.com classic-circuit analysis (Fender Champ 5E1) — cross-reference for stage operating points and the 6V6 single-ended load line",
        "url": "https://www.ampbooks.com/mobile/classic-circuits/fender-champ-5e1/"
      }
    ],
    "verification": {
      "status": "verified",
      "date": "2026-07-18T00:00:00.000Z",
      "max_deviation_pct": 14.7
    },
    "contributors": [
      "TheAnalogMaker"
    ]
  },
  "parts": {
    "notes": "Numbering follows the schematic. The AC-line section (power transformer, fuse, line cap) is drawn as annotation only and carries no designator. Values are from the published Champ 5E1 (H-EE) drawing.",
    "items": [
      {
        "ref": "R1",
        "part": "Carbon comp resistor",
        "value": "68 kΩ · ½ W",
        "role": "Input 1 grid stopper"
      },
      {
        "ref": "R2",
        "part": "Carbon comp resistor",
        "value": "68 kΩ · ½ W",
        "role": "Input 2 grid stopper"
      },
      {
        "ref": "R3",
        "part": "Carbon comp resistor",
        "value": "1 MΩ · ½ W",
        "role": "Input leak, jack 1's tip to ground (the V1A grid returns through R1)"
      },
      {
        "ref": "R4",
        "part": "Carbon comp resistor",
        "value": "1.5 kΩ · ½ W",
        "role": "V1A cathode bias"
      },
      {
        "ref": "R5",
        "part": "Carbon comp resistor",
        "value": "100 kΩ · ½ W",
        "role": "V1A plate load"
      },
      {
        "ref": "R6",
        "part": "Carbon comp resistor",
        "value": "1.5 kΩ · ½ W",
        "role": "V1B cathode bias"
      },
      {
        "ref": "R7",
        "part": "Carbon comp resistor",
        "value": "100 kΩ · ½ W",
        "role": "V1B plate load"
      },
      {
        "ref": "R8",
        "part": "Wirewound resistor",
        "value": "470 Ω · 5 W",
        "role": "6V6 cathode bias"
      },
      {
        "ref": "R9",
        "part": "Carbon comp resistor",
        "value": "220 kΩ · ½ W",
        "role": "6V6 grid leak"
      },
      {
        "ref": "R10",
        "part": "Power resistor",
        "value": "22 kΩ · 1 W",
        "role": "Rail dropper B+2→B+3"
      },
      {
        "ref": "R11",
        "part": "Carbon comp resistor",
        "value": "22 kΩ · ½ W",
        "role": "Negative feedback, speaker→V1B cathode"
      },
      {
        "ref": "VR1",
        "part": "Audio-taper potentiometer",
        "value": "1 MΩ",
        "role": "Volume"
      },
      {
        "ref": "C1",
        "part": "Electrolytic capacitor",
        "value": "25 µF · 25 V",
        "role": "V1A cathode bypass"
      },
      {
        "ref": "C2",
        "part": "Coupling capacitor",
        "value": "0.02 µF · 600 V",
        "role": "V1A → volume"
      },
      {
        "ref": "C3",
        "part": "Coupling capacitor",
        "value": "0.02 µF · 600 V",
        "role": "V1B → 6V6 grid"
      },
      {
        "ref": "C4",
        "part": "Electrolytic capacitor",
        "value": "25 µF · 25 V",
        "role": "6V6 cathode bypass"
      },
      {
        "ref": "C5",
        "part": "Electrolytic capacitor",
        "value": "8 µF · 450 V",
        "role": "Filter, B+1 (reservoir)"
      },
      {
        "ref": "C6",
        "part": "Electrolytic capacitor",
        "value": "8 µF · 450 V",
        "role": "Filter, B+2"
      },
      {
        "ref": "C7",
        "part": "Electrolytic capacitor",
        "value": "8 µF · 450 V",
        "role": "Filter, B+3"
      },
      {
        "ref": "L1",
        "part": "Filter choke",
        "value": "≈350 Ω DCR",
        "role": "B+1→B+2 filter (DCR estimated; not marked on the drawing)"
      },
      {
        "ref": "V1",
        "part": "Preamp tube",
        "value": "12AX7",
        "role": "Both gain stages (V1A/V1B)"
      },
      {
        "ref": "V2",
        "part": "Power tube",
        "value": "6V6GT",
        "role": "Single-ended output"
      },
      {
        "ref": "V3",
        "part": "Rectifier tube",
        "value": "5Y3GT",
        "role": "Full-wave rectifier (V3A/V3B)"
      },
      {
        "ref": "T1",
        "part": "Output transformer",
        "value": "≈5 kΩ : 8 Ω",
        "role": "Single-ended output (impedance not marked on the drawing; typical SE 6V6 load)"
      },
      {
        "ref": "—",
        "part": "Power transformer",
        "value": "HT · 6.3 V · 5 V",
        "role": "HT secondary (voltage not marked; +320 V reservoir implies ≈325-0-325) + heater and rectifier windings"
      },
      {
        "ref": "—",
        "part": "Line capacitor",
        "value": "0.05 µF · 600 V",
        "role": "AC line to chassis, on the transformer side of the fuse"
      },
      {
        "ref": "—",
        "part": "Fuse",
        "value": "2 A",
        "role": "AC-line fuse"
      }
    ]
  },
  "publishedVoltages": {
    "source": "Fender Champ 5E1 (H-EE) drawing, printed chart: rails +320/+305/+260, 12AX7 plates +150 and cathodes +1.5, 6V6 cathode +19. B+1 (+320 reservoir) is the simulation reference; pin values apply to both 12AX7 sections (symmetric stages).",
    "nodes": {
      "BP2": {
        "chart": 305,
        "tol_pct": 8,
        "note": "output B+ after the choke — 6V6 plate (via OT) and screen"
      },
      "BP3": {
        "chart": 260,
        "tol_pct": 8,
        "note": "preamp node after the 22 kΩ dropper"
      },
      "P1A": {
        "chart": 150,
        "tol_pct": 20,
        "note": "12AX7 V1A plate, chart pin value"
      },
      "P1B": {
        "chart": 150,
        "tol_pct": 20,
        "note": "12AX7 V1B plate, chart pin value"
      },
      "K1A": {
        "chart": 1.5,
        "tol_pct": 20,
        "note": "12AX7 V1A cathode, chart pin value (bypassed 25 µF)"
      },
      "K1B": {
        "chart": 1.5,
        "tol_pct": 20,
        "note": "12AX7 V1B cathode (unbypassed; NFB 22k parallels at DC)"
      },
      "K2": {
        "chart": 19,
        "tol_pct": 20,
        "note": "6V6GT cathode, chart pin value (470 Ω, 25 µF bypass)"
      }
    }
  },
  "operatingPoint": [
    {
      "node": "BP2",
      "chart": 305,
      "sim": 305.218,
      "disputed": false,
      "dev_pct": 0.07147540983607138,
      "tol_pct": 8,
      "gated": true,
      "within": true,
      "note": "output B+ after the choke — 6V6 plate (via OT) and screen",
      "dispute_note": ""
    },
    {
      "node": "BP3",
      "chart": 260,
      "sim": 264.117,
      "disputed": false,
      "dev_pct": 1.5834615384615458,
      "tol_pct": 8,
      "gated": true,
      "within": true,
      "note": "preamp node after the 22 kΩ dropper",
      "dispute_note": ""
    },
    {
      "node": "P1A",
      "chart": 150,
      "sim": 172.09,
      "disputed": false,
      "dev_pct": 14.726666666666668,
      "tol_pct": 20,
      "gated": true,
      "within": true,
      "note": "12AX7 V1A plate, chart pin value",
      "dispute_note": ""
    },
    {
      "node": "P1B",
      "chart": 150,
      "sim": 169.321,
      "disputed": false,
      "dev_pct": 12.880666666666665,
      "tol_pct": 20,
      "gated": true,
      "within": true,
      "note": "12AX7 V1B plate, chart pin value",
      "dispute_note": ""
    },
    {
      "node": "K1A",
      "chart": 1.5,
      "sim": 1.38,
      "disputed": false,
      "dev_pct": 8.000000000000007,
      "tol_pct": 20,
      "gated": true,
      "within": true,
      "note": "12AX7 V1A cathode, chart pin value (bypassed 25 µF)",
      "dispute_note": ""
    },
    {
      "node": "K1B",
      "chart": 1.5,
      "sim": 1.331,
      "disputed": false,
      "dev_pct": 11.26666666666667,
      "tol_pct": 20,
      "gated": true,
      "within": true,
      "note": "12AX7 V1B cathode (unbypassed; NFB 22k parallels at DC)",
      "dispute_note": ""
    },
    {
      "node": "K2",
      "chart": 19,
      "sim": 18.972,
      "disputed": false,
      "dev_pct": 0.14736842105262468,
      "tol_pct": 20,
      "gated": true,
      "within": true,
      "note": "6V6GT cathode, chart pin value (470 Ω, 25 µF bypass)",
      "dispute_note": ""
    }
  ],
  "checks": [
    {
      "id": "dc",
      "title": "DC operating point",
      "status": "Verified",
      "summary": "7 reference nodes are within tolerance. Maintainer verification is recorded for 2026-07-18; changes since then are awaiting maintainer re-review.",
      "details": [
        "The circuit's facts (netlist, reference voltages, parts list, both drawings' connections, capacitor polarity marks and heater declarations) have changed since the maintainer's review, or no review fingerprint is on record yet. The badge stands on its date until the maintainer re-reviews.",
        "This compares simulated DC conditions with the cited reference. It does not test sound, physical construction or every part of the circuit."
      ],
      "tone": "checked"
    },
    {
      "id": "schematic",
      "title": "Schematic against DC model",
      "status": "Checked",
      "summary": "Connectivity of modelled components is checked on every change.",
      "details": [
        "Parts outside the DC model need separate checks and source review."
      ],
      "tone": "checked"
    },
    {
      "id": "board",
      "title": "Board against DC model",
      "status": "Checked",
      "summary": "Connectivity of modelled components is checked on every change.",
      "details": [
        "This does not establish heater wiring or physical spacing."
      ],
      "tone": "checked"
    },
    {
      "id": "drawings",
      "title": "Schematic against board",
      "status": "No open findings",
      "summary": "No disagreement is listed in the published comparison.",
      "details": [
        "A finding identifies a difference or a coverage gap. The factory source must decide which drawing, if either, needs correction.",
        "0 sheet-only parts are explicitly excluded. Heaters and the pilot lamp are checked separately."
      ],
      "tone": "checked"
    },
    {
      "id": "heaters",
      "title": "Heater and filament wiring",
      "status": "Checked",
      "summary": "The declared heater circuits cover the drawing and pass their separate wiring check.",
      "details": [],
      "tone": "checked"
    },
    {
      "id": "polarity",
      "title": "Capacitor polarity",
      "status": "Checked",
      "summary": "5 capacitor markings agree with the model's voltage ordering.",
      "details": [
        "This check uses DC voltage ordering; source review establishes markings the model cannot decide."
      ],
      "tone": "checked"
    }
  ],
  "corrections": [
    {
      "id": "5e1-input-leak-2026-10-03",
      "date": "2026-10-03",
      "amps": [
        "5e1"
      ],
      "title": "5E1 input grid-leak position",
      "description": "The 1 MΩ input resistor now hangs from jack 1's tip, on the jack side of its 68 kΩ, as the factory drawing shows. The schematic had it on the grid, and the board wired it to the grid pin. No operating point changes.",
      "commit": "be65a613ffaf27966770568837d77c4ea1b4dfb9",
      "url": "https://github.com/TheAnalogMaker/circuit-codex/commit/be65a613ffaf27966770568837d77c4ea1b4dfb9"
    }
  ],
  "sourceDirectory": "https://github.com/TheAnalogMaker/circuit-codex/tree/ebddc3fd2cf887dca010bbe60487d7391ea6c052/amps/5e1"
}