Why the Phono Stage Matters
A turntable does not make sound on its own. It needs a cartridge to read the groove and a phono stage to bring that tiny signal up to line level while applying the RIAA equalization that every record is cut with. That makes the phono preamplifier one of the most important links in a vinyl system, because everything downstream can only be as good as what this stage delivers. MoFi Electronics, the hardware division of Mobile Fidelity Sound Lab, builds two phono stages that AEA carries, and both were shaped by the same design thinking led by Peter Madnick.
Specifications compared
| Specification | UltraPhono Pro | MasterPhono |
|---|---|---|
| Type | MM/MC phono preamplifier | MM/MC phonostage, dual-chassis (power/signal isolation, low noise, separate grounding) |
| Frequency Response | — | 10Hz–50KHz ±0.20dB |
| Inputs | Single input (all-analog) | RCA/XLR: Voltage & Current inputs, Trans-impedance dynamic loading |
| Outputs | Balanced XLR and single-ended RCA | Single ended RCA and Balanced XLR output |
| Gain | — | Selectable gain for MM or MC 40db, 50db, 60db, 70db |
| Signal to Noise Ratio | — | 93dB (MM), 85dB (MC) |
| Total Harmonic Distortion | — | 10mV@1KHZ MM low: 0.005% A-Weighted; 10mV@1KHZ MM high: 0.005% A-Weighted; 1mV@1KHZ MC low: 0.010% A-Weighted; 1mV@1KHZ MC high: 0.013% A-Weighted |
| Power Supply | — | Cascaded voltage regulation, ultra-low noise |
| Dimensions (W x H x D) | 17 x 2.5 x 11.35 in | 17" x 3.5" x 15.75" (43.2 x 8.9 x 40 cm) |
| Weight | 7 lbs | 15 lb / 6.8 kg |
| Cartridge Loading | Five settings (front panel) | — |
| Cartridge Support | — | Moving magnet and moving coil |
| Circuit Design | — | Discrete with separate power supply |
| Circuitry | — | Fully discrete balanced circuitry, servo-controlled, DC-coupled, high pass filter |
| Designer | — | Developed with Peter Madnick |
| Equalization | — | Passive RIAA: Precise parts, NOS capacitors, accurate resistors |
| Gain Settings | Three RCA settings and three balanced XLR settings (front panel) | — |
| Gain Stages | Fully discrete J-FET/MOSFET | — |
| Loading | — | 15 Ohms, 30 Ohms, 50 Ohms, 75 Ohms, 100 Ohms, 500 Ohms, 1K Ohms, 10K Ohms, 47K Ohms+150pF, & “Custom” |
| Max Output | — | @1% THD, 10 Volts RMS |
| Metering | — | Dual Function VU meters for monitoring or cartridge calibration |
| Remote Control | — | Remote controlled: Input, gain, mute, mono, meter, subsonic filter |
| RIAA Accuracy | — | +/- 0.05db |
| RIAA Equalization | Passive, zero-feedback | — |
| Signal to Noise | 93dB (MM); 85dB (MC) | — |
| Warranty | — | Five years parts & labor |
The Shared MoFi Design
Across this range MoFi commits to a few consistent principles. Both models use discrete gain circuitry rather than off the shelf chips, and both apply passive RIAA equalization for a natural presentation. Both handle moving magnet and moving coil cartridges, so they pair readily with the moving magnet Tracker series cartridges as well as with higher output and lower output designs. Both also give you the flexibility to set gain and cartridge loading, which is what lets you dial in the sound of your specific cartridge instead of accepting a fixed compromise. And both provide balanced XLR and single ended RCA outputs, so they slot into a wide variety of systems.
The difference between the two comes down to design goal. One is a focused, front panel friendly single input stage. The other is a reference component built for the most demanding setups and for listeners who run more than one cartridge.
The Models by Tier
Everyday Reference: MoFi UltraPhono Pro
The MoFi UltraPhono Pro is a single input, all analog MM and MC phono preamplifier with everything you need placed right on the front panel. It offers three RCA gain settings and three balanced XLR gain settings, along with five cartridge loading settings, so you can tune it to your cartridge without reaching behind the chassis. Inside, fully discrete J-FET and MOSFET gain stages feed a passive, zero feedback RIAA equalization network. It is rated at 93dB signal to noise with a moving magnet cartridge and 85dB with a moving coil, and it provides both balanced XLR and single ended RCA outputs from a compact chassis.
This is the stage for the listener who wants a genuinely high performing, easy to live with phono preamplifier for a single turntable. The front panel controls make experimentation approachable, and the balanced outputs mean it is ready for a balanced preamplifier or integrated amplifier if you have one.
The Reference: MoFi MasterPhono
The MoFi MasterPhono is the reference statement in the range, developed with Peter Madnick. It provides two inputs, each independently configurable, so you can keep two arms or two cartridges set up at once and switch between them with their own gain and loading. Gain is fully adjustable on each input, and the resistive and capacitive loading spans a wide range of settings including 15, 30, 50, 75, 100, 500, 1K, 10K and 47K ohms, plus a Custom setting for cartridges that want something specific. The circuit is discrete with a separate power supply to keep noise away from the sensitive audio stages, RIAA equalization is passive, and total harmonic distortion with a moving magnet cartridge measures around 0.005 percent. It too offers balanced XLR and single ended RCA outputs.
This is the stage for the listener chasing the last measure of resolution, for anyone running two tables or two arms, and for those with a demanding low output moving coil cartridge that benefits from precise, granular loading.
Which Should You Buy by Scenario
You have one turntable and want serious sound without fuss
Choose the UltraPhono Pro. Its front panel gain and loading make setup straightforward, and it pairs beautifully with a MoFi belt drive deck such as the UltraDeck fitted with a Tracker cartridge.
You run two cartridges or two arms
Choose the MasterPhono. Its two independently configurable inputs are exactly what a dual arm or two table setup needs, so you can keep a moving magnet and a moving coil ready at all times.
You have a demanding low output moving coil and want maximum tuning
Choose the MasterPhono for its extensive loading range and Custom setting, plus its separate power supply for a very low noise floor.
You want a balanced signal path into a balanced amplifier
Either model works, since both offer balanced XLR outputs. The UltraPhono Pro even offers dedicated balanced gain settings, while the MasterPhono brings its reference circuit and dual inputs to a fully balanced system.
You are building around a growing system
If you expect your analog front end to expand, the MasterPhono gives you the most headroom to grow into. If you want focused excellence for a single deck now, the UltraPhono Pro is the natural home.
A Note on the Rest of the Chain
Remember that the phono stage is one piece of the vinyl puzzle. You still need a turntable and a compatible cartridge, and some MoFi decks ship without a cartridge, so plan for one. From there your phono stage feeds a preamplifier or integrated amplifier and speakers, such as the concentric point source SourcePoint designs by Andrew Jones, driven by a quality amplifier from another brand AEA carries since MoFi does not build amplifiers.
Frequently Asked Questions
Which should I choose if I have one turntable and want serious sound without fuss?
Choose the UltraPhono Pro. Its front panel gain and loading make setup straightforward, and it pairs beautifully with a MoFi belt drive deck such as the UltraDeck fitted with a Tracker cartridge.
Which should I choose if I run two cartridges or two arms?
Choose the MasterPhono. Its two independently configurable inputs are exactly what a dual arm or two table setup needs, so you can keep a moving magnet and a moving coil ready at all times.
Which should I choose if I have a demanding low output moving coil and want maximum tuning?
Choose the MasterPhono for its extensive loading range and Custom setting, plus its separate power supply for a very low noise floor.
Which should I choose if I want a balanced signal path into a balanced amplifier?
Either model works, since both offer balanced XLR outputs. The UltraPhono Pro even offers dedicated balanced gain settings, while the MasterPhono brings its reference circuit and dual inputs to a fully balanced system.
Which should I choose if I am building around a growing system?
If you expect your analog front end to expand, the MasterPhono gives you the most headroom to grow into. If you want focused excellence for a single deck now, the UltraPhono Pro is the natural home.
Come Listen at AEA
AEA is an authorized MoFi Electronics dealer with a showroom in Timonium, Maryland. Demo units rotate and not every model is always set up, so please reach out to arrange a listen or to let us help match a MoFi phono stage to your turntable, cartridge and the rest of your system.