Tools

Cartridge Loading Calculator

Moving-magnet cartridges are sensitive to capacitance. Your tonearm cable adds some, your phono stage adds some more, and the total affects how the treble behaves, so most makers publish a recommended range. This adds up what your system has and checks the total lands inside it.

Moving-magnet and moving-iron cartridges with published electrical figures.

Both are on the cartridge's spec sheet. Not the 47 kΩ input load.

Leave blank for 95 pF — our Clear Wave 2.0 cable, measured per channel.

From the phono stage's manual. Leave blank for a typical 100 pF.

Total load capacitance

195 pF
0300600 pF

This maker publishes no recommended capacitance, so judge by the figures below: where the electrical resonance falls and how the response sits at 10 and 20 kHz.

Electrical response: +0.3 dB at 10 kHz, +1.4 dB at 20 kHz.

Electrical resonance: 48.6 kHz — a broad peak of +8.3 dB at 47.0 kHz, well above the audio band.

Figures: Grado Timbre Opus3, from our database · source: web.archive.org

The working

\(C = 95 + 100 = 195\ \text{pF}\)
\(f_0 = \dfrac{1}{2\pi\sqrt{LC}} = 48.6\ \text{kHz} \quad (L = 55\ \text{mH})\)

The calculation assumes the standard 47 kΩ moving-magnet input, and it covers the electrical behaviour only. A cartridge's mechanical design is tuned on the assumption that it sees the recommended load, which is why staying inside the range matters more than chasing any single figure. Moving-coil cartridges barely react to capacitance, so this calculator is for moving-magnet and moving-iron types. If you don't know your phono stage's input capacitance, its manual usually lists it.

Check the mechanical match too — resonance calculator →