Mobile Fidelity Electronics StudioPhono Phono Stage at Vinyl Sound Toronto Canada

The StudioPhono is a high-performance phono preamplifier from Mobile Fidelity Electronics (MoFi Electronics, USA), available at Vinyl Sound in Toronto, Canada. Like its sibling the UltraPhono, its internal circuitry was developed with the assistance of Tim de Paravicini — the legendary British electronics engineer behind Mobile Fidelity Sound Lab's Gain2 Ultra Analog cutting system, the mastering chain used to produce MoFi's Original Master Recording and UltraDisc One-Step vinyl pressings. The StudioPhono brings that same wide-bandwidth mastering-grade transparency to home analog playback, with selectable gain from 40 dB to 66 dB for both moving-magnet and moving-coil cartridges, six MC loading options from 75 to 47,000 ohms, a switchable subsonic filter, mono mode, and an external power supply that isolates the sensitive gain stages from mains-borne interference. THD measures below 0.01% in MM mode and below 0.012% in MC mode, reflecting a phono stage engineered to resolve the full content of the groove without editorial coloration.

Tim de Paravicini Circuit Design and Mastering-Grade Transparency

The StudioPhono shares its core design philosophy with the UltraPhono: both were developed with circuit input from Tim de Paravicini, whose work on the MoFi Gain2 Ultra Analog cutting lathe established the signal standard against which MoFi's most celebrated vinyl pressings were created. The goal in both cases is to replicate at the playback stage the wide-bandwidth, low-noise transparency that MoFi mastering engineers require when cutting lacquers from original master tapes — a standard that demands accurate RIAA equalization, minimal gain stage coloration, and the ability to resolve low-level musical detail without obscuring it in noise or harmonic distortion. The StudioPhono delivers THD below 0.01% in moving-magnet mode and below 0.012% in moving-coil mode, figures that confirm the amplification stages introduce negligible harmonic distortion across the full gain range. Four selectable gain settings — 40 dB, 46 dB, 60 dB, and 66 dB — accommodate the output range of virtually every MM and MC cartridge in current production, from standard high-output moving-magnet designs at 4mV to 6mV through to ultra-low-output moving-coil cartridges at 0.2mV and below.

Adjustable Loading, Mono Mode, Subsonic Filter, and External Power Supply

Moving-coil cartridge loading is adjustable across six discrete settings — 75, 100, 500, 1,000, 10,000, and 47,000 ohms — allowing the StudioPhono to be tuned to the optimal termination impedance for any MC cartridge. Load impedance directly affects the frequency response, channel balance, and dynamic character of a moving-coil cartridge's output, and having six options ensures the StudioPhono can be matched precisely to cartridges across the full range of MC designs from low-impedance moving-coil to high-impedance designs that prefer a near-MM loading. Moving-magnet cartridges operate at the fixed industry-standard 47,000-ohm load with 100pF input capacitance. A switchable subsonic filter attenuates warp noise and turntable bearing rumble below the audio band, preventing woofer over-excursion and intermodulation distortion that infrasonic energy causes in the downstream amplifier and loudspeakers. Mono mode sums the left and right channels electrically, enabling accurate playback of mono LPs without the channel-difference noise and lateral groove noise that stereo playback of a mono record introduces. The external power supply separates mains conversion from the phono amplifier circuit, eliminating the primary source of noise ingress in sensitive low-level phono stage design and delivering a clean, regulated DC feed to the gain stages.

Key Features

• Tim de Paravicini Circuit Assistance: Internal circuitry developed with input from Tim de Paravicini, the engineer behind MoFi's Gain2 Ultra Analog cutting system, bringing mastering-grade wide-bandwidth transparency to home phono playback.
• Four Selectable Gain Settings: 40 dB, 46 dB, 60 dB, and 66 dB accommodate moving-magnet and moving-coil cartridges across the full range of output voltages in current production.
• Six MC Loading Options: Moving-coil loading adjustable across 75, 100, 500, 1,000, 10,000, and 47,000 ohms for precise cartridge termination and frequency response optimization.
• 47,000-Ohm MM Loading with 100pF Input Capacitance: Industry-standard moving-magnet termination for accurate frequency response and compatibility with all MM cartridges.
• Switchable Subsonic Filter: Attenuates warp noise and turntable rumble below the audio band to prevent woofer over-excursion and downstream intermodulation distortion.
• Mono Mode Switch: Electrically sums left and right channels for accurate mono LP playback, eliminating channel-difference and lateral groove noise inherent in stereo playback of mono records.
• External Power Supply: A separate power supply chassis isolates mains conversion noise from the phono amplifier circuit for a lower noise floor and cleaner analog output.
• THD Below 0.01% MM / 0.012% MC: Low harmonic distortion across both cartridge modes confirms minimal coloration from the gain stages throughout the full operating range.
• Compatible with MM and MC Cartridges: Full MM and MC support in a single chassis eliminates the need for a separate step-up transformer or MC head amplifier.
• MoFi Mastering Heritage: Designed to the transparency standard of Mobile Fidelity Sound Lab's studio chain, making it a natural partner for MoFi Original Master Recording and UltraDisc One-Step vinyl pressings.

Technical Specifications

Frequently Asked Questions

What is the MoFi Electronics StudioPhono?

The StudioPhono is a phono preamplifier from Mobile Fidelity Electronics, with internal circuitry developed in collaboration with Tim de Paravicini — the engineer behind MoFi's Gain2 Ultra Analog cutting system. It supports both moving-magnet and moving-coil cartridges with four selectable gain settings from 40 dB to 66 dB, six MC loading options from 75 to 47,000 ohms, a switchable subsonic filter, mono mode, and an external power supply. THD measures below 0.01% in MM mode and below 0.012% in MC mode. It is available at Vinyl Sound in Toronto, Canada.

What is the difference between the StudioPhono and the UltraPhono?

The StudioPhono and UltraPhono share the same Tim de Paravicini circuit heritage, identical gain settings, identical MC loading options, identical subsonic filter and mono mode switches, and identical external power supply topology. The primary difference is that the UltraPhono adds a built-in Class A headphone amplifier delivering up to 8V RMS and 1.5 watts per channel with a 31-step volume control and mute switch — a complete second component integrated into the same chassis. The UltraPhono also achieves marginally lower THD figures of below 0.006% in MM mode versus the StudioPhono's below 0.01%, and below 0.055% in MC mode versus below 0.012%. The StudioPhono is the more focused, phono-only solution for listeners who have a separate headphone amplifier or do not require headphone listening from their analog source.

How does the StudioPhono compare to the Pro-Ject Phono Box DS3 B and the iFi Audio ZEN Phono?

The StudioPhono holds clear advantages in circuit pedigree and feature depth over both competitors. Against the Pro-Ject Phono Box DS3 B, which offers MM and MC support with adjustable loading and a built-in rechargeable battery power supply, the StudioPhono counters with Tim de Paravicini's direct circuit involvement, a mono mode switch absent from the DS3 B, and the direct lineage to MoFi's mastering chain that no Pro-Ject product can claim. Against the iFi Audio ZEN Phono, a compact MM and MC stage with three gain settings and switchable loading, the StudioPhono offers a fourth gain setting for finer cartridge matching, six MC loading options versus the ZEN Phono's fewer choices, an external rather than internal power supply for lower noise, and mono mode for accurate playback of vintage mono LPs. Neither competitor can trace its circuit topology to the engineer who designed the mastering system used to cut the records the stage is intended to play.

How do I select the correct gain setting on the StudioPhono?

The correct gain setting on the StudioPhono depends on the output voltage of the cartridge and the input sensitivity of the connected amplifier. Moving-magnet cartridges outputting 3mV to 6mV and high-output MC cartridges outputting 1.5mV to 2.5mV are best served by the 40 dB or 46 dB settings, which bring the phono signal to a standard line level without over-driving the downstream component. Low-output MC cartridges outputting 0.4mV to 1mV typically suit the 60 dB setting, while ultra-low-output MC cartridges below 0.3mV require the 66 dB setting. MoFi Electronics provides a cartridge loading guide that cross-references gain and loading settings against specific cartridge models, and Vinyl Sound in Toronto can assist with gain configuration for any cartridge and system combination.

What does the mono mode switch do on the StudioPhono?

The mono mode switch on the StudioPhono electrically sums the left and right input channels into a single mono signal before amplification, which is the correct way to play mono LP records pressed before approximately 1968. Mono records were cut with a purely lateral groove modulation and contain identical information in both channels, so playing them in stereo causes channel-difference noise — any slight difference between the two cartridge channels — to become audible as added noise and coloration. Summing the channels mono eliminates this channel-difference noise and also cancels vertical groove noise and stylus irregularities that are common-mode between channels, producing a quieter, cleaner playback of mono records than stereo mode can achieve.

When should I use the subsonic filter on the StudioPhono?

The subsonic filter on the StudioPhono should be engaged when playing warped records, when the turntable is subject to floor-borne vibration, or when visible woofer pumping is observed during playback. Warp frequencies and turntable bearing rumble typically occupy the 2 Hz to 15 Hz range — well below the audible threshold — but cause woofers to move through large excursions that consume amplifier headroom and generate intermodulation distortion products that fall within the audible band and mask fine musical detail. The filter attenuates this infrasonic content before it reaches the amplifier and loudspeakers. For flat, well-pressed records on a well-isolated turntable such as the MoFi MasterDeck or UltraDeck, the filter can be switched out to preserve the widest possible low-frequency bandwidth.

Where can I buy the MoFi Electronics StudioPhono in Toronto or Canada?

The MoFi Electronics StudioPhono phono stage is available at Vinyl Sound, an authorized Mobile Fidelity Electronics dealer in Toronto, Canada. Vinyl Sound carries the complete MoFi Electronics analog electronics lineup — including the StudioPhono, UltraPhono, MasterPhono, and the full turntable range — and can assist customers across Toronto and Canada with cartridge matching, gain and loading configuration, and complete analog system integration.

Is the StudioPhono suitable for playing MoFi UltraDisc One-Step records?

Yes, the StudioPhono is an ideal partner for MoFi UltraDisc One-Step pressings. Its Tim de Paravicini circuit heritage and wide-bandwidth design philosophy are rooted in the same mastering standard used to cut UltraDisc One-Step lacquers, meaning the StudioPhono is voiced to preserve exactly the resolution and tonal character that MoFi's mastering engineers encoded into those pressings. Combined with a MoFi turntable — the UltraDeck or MasterDeck — and a compatible moving-magnet or moving-coil cartridge, the StudioPhono forms a coherent source-to-output chain aligned with Mobile Fidelity's studio heritage from the original master tape to the listening room.