Yesterday's resonance calculator has grown into a small tools section. There are two additions. Every cartridge in the database now has a page of its own, and there's a second calculator, this one for capacitive loading. Everything is collected at boolaudio.com/tools, which is where the footer's Tools link now points.
The database is browsable now
Until yesterday the 66 cartridges only existed inside a dropdown. Now the database is a page you can read, grouped by brand, and every cartridge has its own page: the published mass and compliance, which standard the maker measured to, the source link, and where it resonates on the Clear Wave and on arms from 8 to 20 g effective mass.
If you're choosing a cartridge for an arm you already own, or the other way round, that last table answers the question directly. Each page also opens either calculator with the figures already filled in.
The loading calculator
Moving-magnet cartridges care about capacitance. The tonearm cable contributes some, the phono stage input contributes more, and the total sets how the cartridge behaves in the top octave. Makers know this, which is why most publish a recommended range. The loading calculator adds up what your system has and checks the total against that range.
An example with real numbers. An Ortofon 2M Red through our 2.0 cable at 95 pF, into a phono stage with a typical 100 pF input, gives 195 pF total. Ortofon's window is 150 to 300 pF, so that lands comfortably inside it.
Now swap in a generic cable at 350 pF. The total becomes 450 pF, the electrical resonance drops from 13.6 kHz to 9.0 kHz, and against the middle of Ortofon's window the response picks up a 2.2 dB hump at 7.2 kHz then falls 5.3 dB behind by 20 kHz. That combination of extra presence and missing air is the classic sound of an overloaded moving magnet, and people routinely blame the cartridge for it.
The calculator shows the working underneath, and the cable field starts at 95 pF because that's what the Clear Wave 2.0 measures per channel. Change it to whatever your cable measures.
Moving-coils sit this one out; their tiny coils barely react to capacitance. The interesting middle case is Grado. Their moving-iron generators carry 45 mH against the 2M Red's 700, which parks the electrical resonance around 50 kHz, far above the audio band. Grado print "non-sensitive to capacitive load" on their spec sheets, and the arithmetic backs them up.
Where the electrical figures come from
The electrical figures follow the same standard as the compliance data: the maker's own published material, with the source linked on every row. Chasing these numbers turned up two things worth passing on.
Sumiko's inductance and coil resistance appear only in their Oyster series user manual, as a table inside a PDF. Their product pages carry a different number, the 1 kHz impedance, and retailers quote it as if it were the coil resistance. It isn't; for the Rainier the two figures are 1,130 and 510 ohms.
Nagaoka publish no inductance at all. Their European distributors' spec tables have the heading and an empty cell under it, which settles where the gap starts. So the MP series sits in the resonance calculator but not in the loading dropdown, and the same goes for Linn's old K-series, whose spec sheets stop at the recommended 47 kΩ. The manual fields accept figures from anywhere if you have a trustworthy one.
Both calculators work without JavaScript, and every result keeps its own address, so a forum question can be answered with a link to the arithmetic.
If a result looks off to you, or there's a cartridge we should add to the database, leave a comment below or use the contact form. Every correction makes the tools better for the next person.