Головки звукоснимателя — MoFi Electronics ULTRATRACKER MM PHONO

MoFi Electronics builds the UltraTracker as a moving-magnet cartridge, hand-assembled in Japan around a housing milled in the United States. Like the rest of the current MoFi cartridge range, it was developed in collaboration with Spiral Groove founder Allen Perkins. Sold separately it is valued at USD 499, and it is also the cartridge that MoFi fits at the factory to the UltraDeck turntable in the UltraDeck +U package, listed at USD 1,799 for the turntable and cartridge together.

Key specs that matter

MoFi classifies the generator as a dual magnet (MM) stereo type. The nude-elliptical diamond is fixed to an aluminium cantilever, and output is 3.5 mV at 5 cm per second and frequency response runs from 20 Hz to 25,000 Hz. The cartridge presents an impedance of 47 kilohms and a capacitance of 100 pF. Compliance is quoted as 35 x 10e-6 cm per dyne static and 10 x 10e-6 cm per dyne dynamic. Channel separation reaches 27 dB at 1 kHz, with channel balance held within 1.0 dB at the same frequency. Tracking force should be set between 1.8 and 2.2 g, and the whole cartridge weighs 9.7 g.

Engineering and use context

MoFi explains that its cartridges were engineered by looking at how a record is made at its source, namely the cutting lathe used at Mobile Fidelity Sound Lab. The result here is a V-Twin dual-magnet generator that copies the layout of the cutting head that originally makes the grooves. Two low-mass magnets are arranged in a V formation, set parallel with the groove walls. The body is a well-damped block of billet aluminium, used to manage resonances inside the cartridge, and MoFi also cites extensive resonance removal work and advanced damping materials in the design. MoFi chose the nude-elliptical diamond for its low tip mass, which the company links to tracking of complex passages and retrieval of fine detail from the groove. The MoFi range currently lists three moving-magnet models - the StudioTracker, the UltraTracker and the MasterTracker - plus the UltraGold MC and StudioSilver MC for moving-coil buyers.

Pairing

The high output is intended for a moving-magnet phono input. MoFi's UltraPhono Pro offers a 47 kilohm loading position with a lowest RCA gain step of 40 dB. On the StudioDeck, the tonearm is specified for cartridges from 5 g to 10 g, a window that covers this model.

Alternatives

Within the same moving-magnet family, the MoFi MasterTracker uses a Micro-Linear stylus and delivers 3 mV.