Practice

Pickup properties

Two pickups can look identical and sound very different. The differences come down to a small set of design variables — magnet, wire, turns, potting — and how they interact electrically with the rest of the signal chain.

A spec sheet rarely tells the full story. Use these properties as a checklist when comparing models or planning a swap.

What shapes a pickup’s sound

Six design variables do most of the work. Change any one and the pickup behaves differently:

Variable What it controls More of it →
Magnet type Field strength and EQ shape Stronger field = more output, tighter low end, brighter top
Coil turns Output level and resonant peak More turns = louder, darker, fatter
Wire gauge Coil density and resistance Thinner wire = more turns per inch = darker, hotter
Inductance Position of the resonant peak Higher inductance = lower peak = darker tone
Potting Resistance to microphonic feedback More potting = quieter at high gain, less “alive”
Pole pieces Field shape under each string Adjustable poles = string-to-string balance control

The rest of this page goes deeper on each one.

Magnet type

The magnet provides the field that the vibrating string disturbs. The choice changes the strength and EQ curve of the pickup.

Magnet Strength Sound String pull Common in
Alnico II Soft Warm, smooth, vintage Low (kind to sustain) Vintage PAF humbuckers, P90s
Alnico III Softest of the alnicos Mellow, smooth attack Very low Early Strat-style pickups
Alnico IV Balanced Even string-to-string response Low–medium Some boutique humbuckers
Alnico V Stronger Bright, punchy, louder Medium Hot Strats, modern bridge humbuckers
Ceramic Very strong Tight lows, aggressive top, high output High Metal-oriented humbuckers
Neodymium Extremely strong (small magnet) Designer-tuned; very efficient Variable Some active and noiseless designs

Wire gauge and turns

The coil is thousands of turns of fine, insulated copper wire. Two related variables matter:

  • Wire gauge (typically AWG 42 or 43 for guitar pickups) — thinner wire fits more turns in the same space and has higher resistance per turn.
  • Number of turns — more turns means more signal voltage from the same string motion (higher output) and a darker, fatter tone.

More turns and thinner wire both push the pickup’s resonant peak down in frequency. That moves the brightness of the pickup; below the peak the response is flatter, above it the response rolls off.

Wire insulation and bobbin

The thin lacquer that insulates the wire (formvar, plain enamel, polysol) and the bobbin material change how tightly the coil packs and how it ages. Vintage pickups often spec specific insulations because hand-wound 1950s coils used what was available at the time.

Output level

Output is the AC voltage produced by the pickup at the same string motion. It depends on:

  • Magnet strength (ceramic > alnico V > alnico II).
  • Number of turns and the geometry of the coil.
  • Distance between the pickup and the strings (closer = louder).

Higher output drives an amp’s preamp into distortion sooner. Lower output preserves dynamic range and clean headroom. There is no “better” — just match the pickup to the rig and the music.

Inductance, capacitance, resonant peak

A pickup is electrically a coil (inductor) with some self-capacitance, loaded by the volume pot, the tone pot and cap, the cable’s capacitance, and the amp’s input impedance. Together these form a resonant low-pass filter.

  • Inductance (Henries) — how much voltage the coil can build per turn. Higher inductance = lower resonant peak = darker tone.
  • Self-capacitance + cable capacitance — together they tune the resonant peak with the inductor.
  • Resonant peak — the frequency where the pickup is loudest before rolling off. A typical Strat single coil peaks around 5–7 kHz; a vintage humbucker around 2–3 kHz.

This is why a long cable sounds “darker” than a short one — more capacitance pulls the peak down.

Potting

“Potting” means dipping the wound coil in melted wax (or sometimes epoxy) to lock the wires together. Unpotted pickups can become microphonic at high volume — the coil itself moves, picking up sound from the air or feedback.

Potting Feedback resistance Tradeoff Typical use
Wax-potted High Less “alive” than unpotted Modern factory pickups, high-gain rigs
Lightly potted Medium Compromise between dynamics and feedback resistance Boutique vintage-spec pickups
Unpotted Low Squeals in high-gain rigs Vintage clones, recording sessions, low-gain players

Pole pieces

The metal slugs or screws under each string. Slug poles give a slightly different field and EQ to screw poles, which is part of the “asymmetry” in a humbucker. Adjustable screw poles let you balance string-to-string output.