Mobile Fidelity - StudioPhono Phono Preamplifier

MoFi’s American-made entry into serious vinyl playback: an all-analog MM/MC phono stage with four switch-selected gain settings, six MC loading options, and switchable mono and subsonic filters.

The StudioPhono was designed to replicate the transparency that Mobile Fidelity Sound Lab’s mastering engineers demand. MoFi credits Tim de Paravicini — the designer responsible for Mobile Fidelity’s Gain2 Ultra Analog cutting system — with having assisted with the internal circuitry, to ensure your analog system faithfully reproduces the music held in the LP groove.

Four gain positions (40dB, 46dB, 60dB and 66dB) cover everything from high-output moving magnets to low-output moving coils. It is a four-position switch rather than a continuously variable control, and the switches sit on the underside of the chassis so no tools are needed. Moving-coil loading is selectable across six values from 75 ohms to 47k, which is where the “adjustable loading” specification applies; in moving-magnet mode the load is fixed at 47k ohms and 100pF.

The switchable mono mode delivers improved image stability and richer tone on mono pressings, while the subsonic filter keeps warp and rumble energy out of the rest of the system. An external power supply keeps transformer noise away from the low-level audio circuitry, and MoFi describes the unit as handcrafted in the USA.

One point of difference worth knowing before you choose: the StudioPhono has no headphone output. If you want the same phono circuit with a Class A headphone amplifier built in, that is MoFi’s separate UltraPhono, which remains a current product. Note also that the UltraPhono is a different and much less expensive product than the UltraPhono Pro, despite the similar name.

Features

• Moving magnet and moving coil compatible
• Four switch-selected gain positions: 40dB, 46dB, 60dB, 66dB
• Six selectable moving-coil loading values from 75Ω to 47kΩ
• Moving-magnet loading fixed at 47kΩ / 100pF
• Switchable mono mode for improved image stability and richer tone
• Subsonic filter to reject warp and rumble energy
• Tool-free adjustment — switches on the underside of the chassis
• External power supply isolates transformer noise from the audio circuitry
• Internal circuitry assisted by Tim de Paravicini, designer of MoFi’s Gain2 Ultra Analog cutting system
• Handcrafted in the USA
• No headphone output — see MoFi’s UltraPhono if you need one

Specifications

• Type: All-analog MM/MC phono preamplifier
• Gain: Four switch-selected positions: 40dB, 46dB, 60dB, 66dB. Not continuously variable
• THD: Less than 0.01% (MM) / less than 0.012% (MC)
• Load Impedance (MM): 47,000 Ω fixed
• Load Impedance (MC): Selectable — 75, 100, 500, 1k, 10k, 47k Ω
• Input Capacitance: 100pF
• Filters: Switchable mono; switchable subsonic
• Headphone Output: Not fitted
• Power Supply: External
• Origin: Handcrafted in the USA
• Note: MoFi publishes no dimensions, weight, warranty term, signal-to-noise ratio, output impedance, RIAA accuracy or frequency response for this model. Dimension figures circulating at dealers conflict with each other and are not MoFi data