Audio T Verdict
The Rega Fono MC Mk4 is a compact and highly capable phono stage for low-output moving-coil cartridges. Its adjustable loading and two gain settings provide considerably more flexibility than its simple exterior might suggest.
Rega uses a low-noise Linear Systems LSK389 FET within the discrete input stage, followed by a carefully developed RIAA equalisation circuit using a MUSE operational amplifier and polypropylene capacitors.
The factory settings are already matched to Rega's own moving-coil cartridges, making it easy to use with the Ania, Ania Pro, Apheta 3 or Aphelion 2. The rear DIP switches also allow it to be adjusted for many suitable cartridges from other manufacturers.
It does not offer the refinement or power-supply sophistication of Rega's Aos MC or Aura Reference MC, but it provides an accessible route into proper low-output moving-coil playback without unnecessary controls or complication.
Rega Fono MC Mk4 Phono Stage
The Rega Fono MC Mk4 is a dedicated external phono pre-amplifier designed for low-output moving-coil cartridges.
A moving-coil cartridge produces an extremely small electrical signal. The Fono MC amplifies this signal to a level suitable for a conventional amplifier line input while applying the RIAA equalisation required for accurate record playback.
Gain, input resistance and capacitance can be adjusted using four DIP switches located on the rear panel. This allows the phono stage to be matched to Rega cartridges and a wide selection of suitable third-party moving-coil designs.
The Mk4 is housed in Rega's compact aluminium case, matching the
Rega Fono MM Mk5
and
Rega Neo Mk2
.
Why Does a Moving-Coil Cartridge Need a Phono Stage?
A low-output moving-coil cartridge generates a signal measured in fractions of a millivolt. This is considerably lower than the output from a moving magnet cartridge and far below the level required by a normal amplifier line input.
Records are also manufactured using an RIAA frequency curve that reduces low frequencies and increases high frequencies during cutting.
The Fono MC therefore performs two essential tasks:
- It provides the high level of gain required by a low-output moving-coil cartridge
- It applies the inverse RIAA curve to restore the correct frequency balance
Connecting a low-output moving-coil cartridge directly to a moving magnet or line input would normally result in extremely low volume and unsuitable cartridge loading.
Dedicated Low-Output Moving-Coil Design
The Fono MC Mk4 has been designed specifically for conventional low-output moving-coil cartridges.
It provides considerably more gain than a moving magnet phono stage and offers adjustable resistance and capacitance to suit different cartridge requirements.
It is not intended for moving magnet cartridges. Some high-output moving-coil designs are also intended to operate through a moving magnet input, so the cartridge manufacturer's recommendation should always be checked.
Low-Output Moving Coil
- Use the Rega Fono MC Mk4
- Requires substantial phono-stage gain
- Loading should be matched to the cartridge
- Includes two gain settings
Moving Magnet
- Use a moving magnet phono stage
- Normally requires 47 kO loading
- Produces a much higher output level
- Consider the Rega Fono MM Mk5
Low-Noise LSK389 FET Input Stage
The first amplification stage uses a Linear Systems LSK389 low-noise dual FET within an all-discrete circuit.
Low noise is particularly important because the incoming cartridge signal is extremely small. Noise introduced at this point would be amplified by every following stage.
The high input impedance of the FET also helps reduce the direct loading effect of the amplifier circuit on the cartridge generator.
- Linear Systems LSK389 low-noise FET
- All-discrete input stage
- Designed for very low cartridge output levels
- High input impedance
- Low-noise and high-linearity circuit
- No digital processing within the signal path
MUSE RIAA Equalisation Amplifier
A MUSE operational amplifier is used within the RIAA equalisation section.
Polypropylene capacitors are used within both the signal path and RIAA equalisation network, where accurate and stable component values are particularly important.
Rega specifies RIAA accuracy of better than plus or minus 0.2 dB between 100 Hz and 100 kHz when used with an appropriate output load.
Adjustable Cartridge Loading
Four rear-panel DIP switches control the input resistance, input capacitance and gain.
Each channel is adjusted together, so one set of switches configures the complete stereo phono stage.
Switch Off Before Changing Settings
Switch off the Fono MC and partnering amplifier before altering the rear DIP switches.
Begin with the cartridge manufacturer's recommended values and change only one setting at a time.
Resistance Settings
Input resistance affects how the moving-coil cartridge is electrically damped by the phono stage.
400 O
Set DIP switches 1 and 2 to Off.
This is the lightest available resistance loading and may suit cartridges that specify a higher load value.
150 O
Set switch 1 to Off and switch 2 to On.
100 O
Set switch 1 to On and switch 2 to Off.
This is the Rega factory setting for its own moving-coil cartridges.
70 O
Set DIP switches 1 and 2 to On.
This provides the heaviest available resistance loading.
Capacitance Settings
DIP switch 3 selects between two input-capacitance values.
1000 pF
Set DIP switch 3 to Off.
This is the factory setting used for Rega moving-coil cartridges.
4300 pF
Set DIP switch 3 to On.
This alternative setting may suit cartridges requiring additional capacitive loading.
Two Gain Settings
DIP switch 4 selects the amount of amplification applied to the cartridge signal.
63.5 dB Gain
Set DIP switch 4 to Off.
This lower setting provides greater input headroom and may suit moving-coil cartridges with a comparatively higher output.
Input sensitivity is 133 µV for a 200 mV output.
69.5 dB Gain
Set DIP switch 4 to On.
This high-gain setting is the factory configuration for Rega moving-coil cartridges.
Input sensitivity is 67 µV for a 200 mV output.
More gain is not automatically better. Excessive gain can reduce headroom, increase the audibility of background noise and make volume control more sensitive.
Factory Settings for Rega Moving-Coil Cartridges
Rega supplies the Fono MC Mk4 configured for its current moving-coil cartridge range.
- Input resistance: 100 O
- Input capacitance: 1000 pF
- Gain: 69.5 dB
- DIP switch 1: On
- DIP switch 2: Off
- DIP switch 3: Off
- DIP switch 4: On
These settings are suitable for Rega's Ania, Ania Pro, Apheta 3 and Aphelion 2 cartridges.
Rega Cartridge Compatibility
Rega Ania
The
Rega Ania
is Rega's entry-level hand-made moving-coil cartridge.
The Fono MC Mk4 provides a natural and straightforward phono-stage partner using the standard factory settings.
Rega Ania Pro
The
Rega Ania Pro
adds a Vital-profile nude diamond stylus to the Ania generator.
It is particularly well matched to Planar 6 and Planar 8 systems using the Fono MC Mk4.
Rega Apheta 3
The
Rega Apheta 3
is electrically compatible with the factory Fono MC settings.
A higher-level phono stage may reveal more of its performance in a sufficiently capable system, so a comparison with the Aos MC or Aura is worthwhile.
Rega Aphelion 2
The
Rega Aphelion 2
is compatible with the Rega factory settings.
As Rega's reference cartridge, it is normally partnered with a correspondingly high-performance stage such as the Aura Reference MC.
Compatible Third-Party Cartridges
The Fono MC Mk4 can also be used with many suitable low-output moving-coil cartridges from other manufacturers.
Before connection, check the cartridge manufacturer's recommendations for:
- Recommended load resistance
- Recommended input capacitance
- Nominal output voltage
- Required phono-stage gain
- Whether the cartridge is genuinely low output
The available values do not cover every possible cartridge. Audio T can check compatibility and recommend the nearest appropriate setting before the cartridge is used.
Suitable Rega Turntables
Rega Planar 6
The
Rega Planar 6
with Ania Pro is one of the most natural complete systems for the Fono MC Mk4.
The cartridge connects directly to the Fono MC, which then feeds a normal line input on the amplifier.
Rega Planar 8
The
Rega Planar 8
can be specified with an Ania Pro or Apheta 3 moving-coil cartridge.
Both cartridges can use the factory Rega loading configuration.
Rega Planar 10
The
Rega Planar 10
is available with the Apheta 3 or Aphelion 2.
The Fono MC is electrically compatible, although a more revealing phono stage should also be considered at this system level.
Rega Naia
The
Rega Naia
is normally partnered with the Aphelion 2 and a reference phono stage.
The Fono MC will operate with the cartridge, but the Aura is the more appropriate Rega partner for a complete Naia system.
How to Connect the Fono MC Mk4
- Check the cartridge manufacturer's recommended loading and gain.
- Switch off the turntable, Fono MC and amplifier.
- Set the four rear DIP switches to the required positions.
- Connect the turntable RCA plugs to the Fono MC input.
- Connect the turntable earth lead if one is provided.
- Connect a stereo RCA interconnect from the Fono MC output to a normal amplifier line input.
- Connect the supplied Rega 24 V AC power supply.
- Reduce the amplifier volume.
- Switch on the Fono MC before switching on the amplifier.
- Select the appropriate amplifier input and gradually increase the volume.
Connect the Output to a Line Input
The Fono MC output must connect to an amplifier input marked AUX, CD, Line, Tuner or similar.
Do not connect it to another moving magnet or moving coil phono input. Doing so would apply excessive gain and RIAA equalisation twice, causing severe distortion.
Turntable Earthing
An earth terminal is provided on the rear panel.
Connect the separate earth wire if one is supplied with the turntable or tonearm.
Many Rega turntables earth the tonearm through the signal cable and do not use a separate wire, so it may be normal for the terminal to remain unused.
If hum is present, check the RCA plugs, earth connection, cable routing and proximity of the turntable to power adaptors or amplifier transformers.
Powering the Fono MC
A front-panel button switches the unit on and off.
The Rega logo illuminates red while the phono stage is operating.
Rega advises switching on the Fono MC before the partnering amplifier. The initial power surge may otherwise create an audible thump through the loudspeakers.
Keep the amplifier volume low while switching the phono stage or changing connections.
Positioning and Reducing Hum
Moving-coil cartridge signals are extremely small and can be affected by nearby electrical equipment.
Position the Fono MC on a stable surface away from large transformers, power amplifiers, mains distribution blocks and wireless equipment where possible.
Keep the turntable cable away from mains leads and speaker cables. Where power and signal cables must cross, arrange them at approximately a right angle.
Do not place the power adaptor directly beside the turntable cartridge, tonearm base or low-level signal cable.
Fono MC, Aos MC or Aura?
Rega Fono MC Mk4
The Fono MC is the most accessible dedicated Rega moving-coil phono stage.
It provides adjustable loading, two gain settings and factory configuration for all Rega moving-coil cartridges.
It is a natural choice for the Ania and Ania Pro, and a sensible starting point for many third-party low-output cartridges.
Rega Aos MC
The
Rega Aos MC
is a higher-performance adjustable moving-coil stage based heavily on the Aura Reference design.
It is suitable for more revealing Planar 8, Planar 10 and equivalent systems where a lower noise floor and greater resolution are priorities.
Rega Aura Reference MC
The
Rega Aura Reference MC
is Rega's reference phono stage.
It is the natural choice for the Planar 10, Naia, Apheta 3 and Aphelion 2 when the rest of the system can reveal the additional performance.
What Changed with the Mk4?
The Fono MC Mk4 was introduced as part of Rega's updated compact electronics range.
The established Fono MC performance was retained while the product was rehoused in the redesigned aluminium enclosure also used by the Fono MM Mk5 and Neo Mk2.
The audio circuit itself was originally developed using knowledge gained during the design of Rega's higher-level phono stages.
What the Fono MC Mk4 Does Not Include
No Moving Magnet Input
- Not intended for Rega Carbon or Nd cartridges
- No 47 kO moving magnet setting
- Use the Rega Fono MM Mk5 instead
- Check high-output MC cartridge requirements
No Digital or USB Output
- No USB recording connection
- No analogue-to-digital conversion
- No computer audio interface
- Purely analogue signal path
No Balanced Connections
- RCA input only
- RCA output only
- No balanced XLR input
- No balanced XLR output
No Volume or Headphone Control
- Not a conventional pre-amplifier
- No listening-volume control
- No headphone socket
- Requires an amplifier or pre-amplifier
No Remote or Automatic Standby
- Front-panel power control only
- No remote handset
- No automatic standby
- No app or wireless control
Who Is the Rega Fono MC Mk4 For?
A Good Choice If You:
- Use a low-output moving-coil cartridge
- Own a Rega Ania or Ania Pro
- Want adjustable resistance and capacitance
- Need a choice of two gain settings
- Want a dedicated external MC phono stage
- Prefer simple rear-panel adjustment
- Do not require USB recording
- Want to upgrade from a basic built-in MC input
- Need compatibility with suitable third-party cartridges
- Want a compact phono stage made to match other Rega components
Consider Another Option If You:
- Use a moving magnet cartridge
- Use a high-output MC designed for an MM input
- Need continuously variable loading
- Want balanced XLR connections
- Need a USB output for recording vinyl
- Want both moving magnet and moving coil inputs
- Own a reference cartridge and want the highest Rega performance
- Need a headphone amplifier or volume control
Key Features
- Dedicated low-output moving-coil phono stage
- Designed and made in England
- Linear Systems low-noise LSK389 FET
- All-discrete input amplification stage
- MUSE operational amplifier within the RIAA stage
- Polypropylene signal-path capacitors
- Polypropylene RIAA equalisation capacitors
- Four selectable resistance settings
- 70 O, 100 O, 150 O and 400 O loading
- Two selectable capacitance settings
- 1000 pF and 4300 pF capacitance
- Two selectable gain settings
- 63.5 dB and 69.5 dB gain
- Factory configured for all Rega moving-coil cartridges
- Compatible with many third-party low-output MC cartridges
- Stereo RCA input
- Stereo RCA output
- Separate turntable earth terminal
- Front-panel power button
- Red illuminated Rega logo
- Compact aluminium case
- Rega 24 V AC power supply included
- Lifetime limited warranty against confirmed manufacturing defects
Included Accessories
- Rega Fono MC Mk4 Phono Stage
- Rega 24 V AC power supply
- User documentation
A separate stereo RCA interconnect is required between the Fono MC output and the amplifier unless a suitable cable is already available.
Frequently Asked Questions
What does the Rega Fono MC Mk4 do?
It amplifies the very low-level signal from a moving-coil cartridge and applies the correct RIAA equalisation before passing the signal to a normal amplifier line input.
Is it suitable for moving magnet cartridges?
No. Moving magnet cartridges require a dedicated moving magnet stage such as the Rega Fono MM Mk5.
Can it be used with a high-output moving-coil cartridge?
Some high-output moving-coil cartridges are designed for a moving magnet input rather than a high-gain MC stage. Check the cartridge manufacturer's recommendations before connection.
Which Rega cartridges are compatible?
The factory settings are suitable for the Rega Ania, Ania Pro, Apheta 3 and Aphelion 2.
What are the Rega factory settings?
Rega configures the unit for 100 O resistance, 1000 pF capacitance and 69.5 dB high gain.
Can it be used with cartridges from other manufacturers?
Yes. It is compatible with many low-output moving-coil cartridges whose loading and gain requirements fall within the available settings.
How is the loading adjusted?
Four DIP switches on the rear panel select resistance, capacitance and gain.
Which resistance settings are available?
The available values are 70 O, 100 O, 150 O and 400 O.
Which capacitance settings are available?
The Fono MC provides 1000 pF and 4300 pF settings.
How much gain does it provide?
The two available settings are 63.5 dB and 69.5 dB at 1 kHz.
Should I always use the highest gain setting?
No. Use the setting appropriate for the cartridge output. Excessive gain can reduce headroom and make background noise more apparent.
Where does the turntable connect?
Connect the turntable's RCA plugs to the input sockets on the rear of the Fono MC.
Where does the Fono MC output connect?
Connect it to a normal amplifier line input marked AUX, CD, Line, Tuner or similar.
Can it connect to the MC input on my amplifier?
No. The Fono MC is already a complete phono stage. Its output must connect to a line input rather than another MM or MC input.
Can I use it if my amplifier already has a phono stage?
Yes. Connect the Fono MC to a spare line input and compare it with the amplifier's internal MC stage.
Do I need to use the earth terminal?
Use it when the turntable or tonearm has a separate earth lead. Many Rega turntables earth through the signal cable and do not require a separate connection.
What should I do if the system hums?
Check the RCA plugs, earth connection, cable routing and the distance between the cartridge, Fono MC and nearby power transformers or adaptors.
Which component should be switched on first?
Rega recommends switching on the Fono MC first and then the amplifier, with the amplifier volume turned down.
Is the power supply included?
Yes. The correct Rega 24 V AC power supply is included.
Is an RCA interconnect included?
An output interconnect is not listed among the standard accessories, so a suitable stereo RCA cable is normally required.
Does it have a USB output?
No. It is a purely analogue phono stage and does not include USB recording.
Does it have balanced XLR outputs?
No. The Fono MC uses unbalanced RCA input and output connections.
Does it have a headphone output?
No. Headphones must connect to the amplifier, pre-amplifier or a separate headphone amplifier.
Should I consider the Rega Aos or Aura instead?
The Aos MC and Aura are higher-performance options for more revealing turntables, cartridges and systems. Audio T can arrange a comparison to establish whether the additional performance is worthwhile.
Can Audio T set the DIP switches for my cartridge?
Yes. Provide the cartridge make and model and our store teams can check the recommended loading and gain settings.
Why Buy From Audio T?
- Specialist moving-coil cartridge and phono-stage advice
- Help confirming cartridge output and loading requirements
- Rear DIP-switch setup support
- Demonstrations with Rega Ania, Ania Pro and Apheta cartridges
- Comparisons with the Rega Aos MC and Aura Reference MC
- Turntable setup, cartridge alignment and tracking-force guidance
- Advice on earthing, cable routing and reducing hum
- Help matching the phono stage to your amplifier and wider system
- Part exchange available on suitable equipment
- Ongoing support from the UK's oldest independent specialist Hi-Fi retailer
Contact your local Audio T store
to arrange a demonstration or discuss the correct settings for your moving-coil cartridge.