Musical Fidelity MX-VYNL Phono Stage

DESIGN:

Combination MM/MC external phono stage

NOMINAL GAIN AT 1 KHZ:

MM (low/high): 42 dB / 48 dB
MC (low/high): 57 dB / 63 dB

MAXIMUM OUTPUT LEVEL:

Balanced: 8V RMS
Unbalanced: 4V RMS

MM INPUT IMPEDANCE:

47 kΩ

MM INPUT CAPACITANCE:

50, 100, 200, 300, or 400pf

MC INPUT IMPEDANCE:

10, 20, 50, 100, 200, 400, 800, 1.2k, or 47kΩ

MC INPUT CAPACITANCE:

150 pF

TOTAL HARMONIC DISTORTION AT 1 kHz, 2 V RMS OUTPUT, 10 kΩ LOAD (20 HZ – 20 KHZ BAND):

MM: MC:

Both the discontinued M1-ViNL and the MX-VYNL use the INA217 precision instrumentation amplifier chip from Texas Instruments. This chip is a very low-noise, high-gain amplifier designed to be used with low-output balanced sources which seems to make it a perfect choice for use in a phono amplifier. As implemented by Musical Fidelity, it produces a very precise and balanced sound that accurately reflects the sound of the source and allows for adjustable gain if implemented that way. The maximum gain of this chip is 1000x (or 60dB), so implementations are limited to that amount of gain unless they add more in another gain stage.

Though both designs are based on the INA217, the MX-VYNL…

• has high and low-gain settings vs fixed gain in the M1.
• does not have an LCD display and instead uses a large, continuously-rotating control knob to adjust and display the current MM capacitance and MC resistance setting. Toggle switches on the front and a rear-mounted sliding switch are used for other settings.
• mutes outputs when changing settings where the M1 had continuous output (sometimes with audible pops or clicks when making settings changes while listening).
• adds balanced input via a single 5-pin mini-XLR connector.
• does not have a 12v trigger for remote turn-on/turn-off.
• has an external “wall wart” power supply where the M1 placed the power supply in its chassis alongside other signal-carrying circuitry.

Of these changes, the following offer the best potential for increased audio performance:

• Balanced Input: The primary benefit of balanced interconnects is superior noise rejection due to the use of “differential” signals that allow noise to be canceled by transmitting both negative and positive phase signals and comparing them at the input of the next component in the signal chain. Given the fact that cartridges output a balanced signal and these signals are very low voltage, balanced connections between the cartridge and the phono preamplifier in theory should provide a meaningful signal-to-noise improvement over an unbalanced signal.
• External Power Supply: Removing the power supply from the chassis where low-level signals are processed should help prevent both low-frequency “mains” noise as well as high- frequency interference at the power supply switching frequency from polluting the signal.
• High- and Low-Gain: Two gain settings allow users with high and low-output cartridges to select the most appropriate gain for their system, allowing better matching with downstream equipment. This is a welcome addition because many systems do not have variable input sensitivity and otherwise may not produce enough gain when used with low- output cartridges.

The Musical Fidelity MX-VYNL was shipped in a compact, padded retail box with a power adapter, interchangeable plugs for use in different countries, and a printed copy of the manual. This retail packaging was enclosed in an additional outer box to further protect the unit during shipping.

The following equipment was used with the MX-VYNL in this evaluation:

Cartridges:

• Rega Exact 2 Moving-Magnet cartridge with a high output of 6.8-7.2 mV.
• Dynavector 17d3 Moving-Coil cartridge with a low output of 0.3 mV.

Turntable:

• Linn Sondek LP12 with a Graham Engineering 1.5T tonearm (upgraded to 2.0T specs) and a GreenStreet Audio cast aluminum sub-chassis with SME tonearm mount.

Downstream:

• Koss ESP/950 Electrostatic Headphones with E/90 Energizer
• Meridian G68 AXD
• EAD Powermaster 500 and Rotel RB-1582 MKII Amplifiers
• 3-way custom-built active loudspeakers with Morel and Scan-Speak drivers and MiniDSP 2×10 HD crossover

When first listening to new equipment, I like to use very familiar tracks and initially keep the signal path as simple and pristine as possible; using the Koss ESP/950+E/90 combination directly attached to the MX-VYNL’s unbalanced outputs accomplishes both goals. The ESP/950s are not quite as detailed as the very best electrostatics (like the Stax SR-009), but they are more revealing than most headphones and all but the highest-fidelity loudspeaker systems.

I decided to start with the Rega Exact 2 cartridge because I had not used it since upgrading the sub-chassis and tonearm on my LP12 and switching to the Dynavector 17d3. Given all the upgrades, I was keen to find out how it would sound with a substantially upgraded turntable and the MX-VYNL handling amplification. I fitted the Exact 2 on the Graham tonearm and made all the necessary adjustments before doing any critical listening. For this test, I used unbalanced cables because I had not yet received the special DIN-to-mini-XLR cable (more on this later) required to connect the Graham to the MX-VYNL in balanced mode. I set the MX-VYNL for low gain given the high output of the Exact 2 cartridge and set the capacitance to 100pF per Rega’s documentation. I selected RIAA equalization as I prefer to preserve all of the low-frequency content for critical listening and connected my Koss headphones directly to the unbalanced outputs of the MX-VYNL.

I was immediately surprised to find that the upper midrange and treble harshness that I remembered from evaluating the Rega Exact 2 with a much less optimal tonearm and chassis configuration was now completely gone! In the place of rough edges, I now found smooth, subdued midrange and somewhat attenuated but clear highs. The bass was perhaps a bit too full and loose, but it’s so often hard to get full bass from a turntable that I forgave this transgression.

Another thing I like about this track is that it really helps you listen for proper reproduction of sibilance. On a well set up turntable with a very good phono preamplifier, you’ll hear that some of the S’s are perfectly clean and others (like when Simon sings the lyric “She was physically forgotten…”) have too much sizzle and a little distortion, likely due to microphone overload in the master recording. Some preamplifiers smooth over these subtleties or try to be too “exciting” by overdriving the signal so that all sibilances sound a little distorted and grainy. In this case, the MX-VYNL did a great job of differentiating between the two, so it passed the test with flying colors.

It was at this point that I finally received the special and hard-to-obtain balanced cable from a manufacturer in Wales, UK, named Y. Tome Audio Cables that allowed me to evaluate the MX-VYNL in balanced mode. Moving coil cartridges are inherently balanced with the four pins on the cartridge providing a positive and negative phase signal for each channel and the tonearm usually acting as a common ground (most moving magnet cartridges tie the ground to one of the signal wires, thus preventing fully balanced operation for that channel). If your tonearm uses an SME-style 5-pin DIN connector, this cable will allow you to connect it to the MX-VYNL for fully balanced operation. The price was around $50 USD, which was very reasonable for such a well-made cable. At this point, it was time to switch to the more revealing Dynavector 17d3 and see how much better sound quality the same recordings could muster in balanced mode. After setting up the 17d3, I set the MX-VYNL for 100Ω, set the gain to +6dB, and flipped the switch on the back to “balanced”. I was greeted with a cheery blue LED illuminating the balanced indicator on the front panel indicating it was time for a second pass through these songs.

Graceland’s “Diamonds on the Soles of Her Shoes” was now even more finely drawn, benefiting greatly from the super-resolution and extended, flat frequency response provided by the Dynavector’s short all-diamond cantilever and micro-ridge stylus profile. The subtle phrasing of each male vocalist was now easier to make out, and when the drums came in, they did so with tighter low frequencies than the Rega Exact 2 could muster. I personally feel that high-res digital generally surpasses vinyl in resolution (it certainly betters it in measurements), but I did a short recording of the intro to this song at 24/192kHz on my MOTU Ultralite mk5 audio interface and compared it directly with the Apple Lossless master version of the same song from Apple Music. The differences were very small indeed. My wife, who has better ears than I do, actually slightly preferred the vinyl version recorded through the MX-VYNL. Regardless, nearly matching the sound quality of a lossless digital master recording is no small feat, and the MX-VYNL pulled it off with the help of equally capable upstream equipment.

Moving on to “Tin Pan Alley”, the balanced MX-VYNL extracted more subtle details like guitar reverb and decay. When transients called for it, they were even more explosive than the prior Exact 2/Unbalanced MX combo could muster. This song was less laid back, but in a way that I prefer from an audiophile recording played on a high-fidelity system.

On “Time Further Out”, the drums on “Far More Drums” were just that – Far more. They sounded more detailed, with sharper transients, and were overall punchier while providing more of the nuance (likely from properly rendered harmonics) that help you discern between the different types of drums being used. The piano notes were clearer and their decay was more realistic. On “Unsquare Dance”, the claps now almost sounded as if they were processed using some spatial enhancement effect; they threw a very wide soundstage and seemed to linger longer than with the Exact 2. In a sense, all things were improved as they should be with a step-up in cartridge resolution. This shows the fundamentals of the MX-VYNL are solid allowing it to scale well with better upstream sources.

For bench testing the MX-VYNL, I used the following equipment:

Oscilloscope (used for square wave signal generation and capture):

• Picoscope 2204a

Inverse RIAA Equalization (to convert test signals with flat EQ to RIAA-equalized signals phono stages expect as input):

• Hagerman Audio Labs iRIAA2

THD+N Measurements:

• MOTU Ultralite mk5 Audio Interface
• Room EQ Wizard

With no signal on the unbalanced connection, the spectrum is dominated by the 60Hz mains frequency interference and harmonics above it. This noise is exacerbated by the RIAA equalization which amplifies low frequencies.

When the input is shorted, however, this mains interference goes away.

I was unable to reach the low 101/98dB THD+N published by Musical Fidelity but achieved respectable noise figures of 83-87dB without a signal and approximately 65dB THD+N with an unbalanced signal that improves as the frequency increases and RIAA equalization has less impact. At 1kHz, the THD+N is close to the published specifications.

Intermodulation distortion was very low in level with only one visible side peak over 106dB below the 19kHz and 20kHz dual-tone signals.

10kHz (left) and 20kHz (right) square wave performance is stable with very rounded leading edges due to a slow roll-off in frequencies above 20kHz. The slew rate and frequency range could be greater to support the extended frequency response of some wide bandwidth cartridges like the Dynavector 17d3, but this is more than adequate to cover the audible frequency range.

For the quite reasonable price of $899, it is hard to find much to fault in the Musical Fidelity MX-VYNL Phono Stage.

The MX-VYNL will work with almost any combination of turntable and cartridge and will likely not be the weak link until the price of your upstream vinyl playback system is 5-10 times the price of the MX-VYNL.

The MX-VYNL retains the refined sound of its predecessor while making several noteworthy improvements. Accomplishing this at a lower price makes the MX-VYNL a great value in the world of phono preamplifiers. If your listening room has a suspended wood floor like mine and your preamplifier or processor provides balanced inputs, the MX-VYNL’s balanced outputs will allow placement of your turntable wherever it is least susceptible to footfalls without worry of noise or signal loss between the MX-VYNL and the rest of your system. The only challenge you may face with the MX-VYNL is finding the proper cable to connect it to a turntable with balanced outputs, but such cables are available if you look.