Musical Fidelity M6x DAC - Black

One Box for the Whole Digital Front End

The Musical Fidelity M6x DAC is a full-width converter, a preamplifier and a headphone amplifier in one chassis. Two ES9038Q2M chips run in dual differential mode, one per channel, so each side of the stereo image gets its own conversion rather than sharing a chip.

Everything digital in the house has somewhere to go. There is a coaxial input, two optical, an AES/EBU and a USB Type B. The USB takes PCM to 768kHz and native DSD512, and MQA decodes in hardware rather than in software on your computer.

It Can Run Your System Without a Preamplifier

Both output pairs switch between fixed and variable. Set them variable and the M6x becomes the volume control for a power amplifier or a pair of active speakers. Set them fixed and it hands a clean signal to the preamp you already own.

The 6.3mm headphone output is not an afterthought either. It delivers 1.5 watts per channel into 32 ohms and is specified from 16 ohms upward, so a serious pair of headphones is a cable away rather than another purchase.

Where the Engineering Shows Up on the Bench

Signal-to-noise measures better than 120dB A-weighted at 1kHz and distortion sits under 0.0005%. Channel separation is better than 130dB at 10kHz. Total correlated jitter stays under 12 picoseconds peak to peak, and linearity holds within 0.4dB all the way down to -130dB, which is where cheap converters usually give up.

Seven Filters and an Off Switch for the Lot

Every input is reclocked before conversion. Upsampling can lift incoming PCM to 352.8kHz or 384kHz, and it switches off if you would rather hear the native rate. Seven digital filters and an oversampling-bypass mode let you settle the question by ear rather than by argument.

Power comes through an encapsulated toroidal transformer with a DC blocker and an EMI-filtered inlet. Frequency response runs -0.1dB at 10Hz and -0.4dB at 20kHz. The chassis is 440 by 100 by 390mm and weighs 6.9kg, drawing 20 watts at most and under half a watt in standby.

What Reviewers Are Saying

Phil Gold of SoundStage! Hi-Fi, in a July 15, 2023 review, wrote: "I have yet to hear a DAC at this price level with such natural and realistic sound across such a broad range of music."

He added one setup note worth acting on: "If you already have a good preamp or integrated amp and can bypass the M6x DAC’s volume control, I highly recommend it." The fixed output setting does exactly that.

Who Is This DAC Best For?

• You have more digital sources than inputs — coaxial, two optical, AES/EBU and USB mean the streamer, the TV, the disc player and the computer all stay connected at once.
• You want to lose a box, not add one — variable outputs let the M6x drive a power amp directly, so the preamplifier and its interconnects come out of the rack.
• You listen in headphones seriously — 1.5 watts into 32 ohms from the 6.3mm jack covers most of what you would want to plug in, with no separate amplifier to buy.
• Your library is high resolution — PCM to 768kHz, native DSD512 and hardware MQA decoding mean nothing is downconverted before it reaches the chips.
• You want to choose the streamer yourself — one of our music streamers feeds the M6x's digital inputs and it does the converting

How Does It Connect to Your System?

Put your computer on USB and everything else on the coaxial, optical or AES/EBU inputs. Run the balanced XLR outputs to a power amplifier if you have the cables, or the RCA pair to an integrated amp. Then set the rear switch: variable if the M6x is running volume, fixed if something downstream is.

Headphones plug into the front. The rest of the rack can stay where it is.

Pairs Well With

Building a system around the M6x DAC? These are the natural companions:

• Music Streamer: Puts your network library on the digital inputs — see our Music Streamers.
• Headphones: The front jack has the power for a good pair — see our Headphones.
• Interconnects: Balanced XLR cables for the run to your amplifier — see our Interconnect Cables.
• Audio Rack: A full-width shelf for a full-width box — see our Audio Racks.

Frequently Asked Questions

Which digital inputs does it have?

One coaxial, two optical, one AES/EBU and one USB Type B. The S/PDIF and AES inputs run to 24-bit/192kHz with MQA; USB goes further.

What does the USB input support?

PCM to 32-bit/768kHz, DSD256 over DoP and native DSD512, through a USB Audio Class 2.0 connection.

Can it replace my preamplifier?

Yes. Switch the RCA or XLR outputs to variable and the front control governs volume, so a power amplifier or active speakers can connect directly.

Which headphones will it drive?

The 6.3mm output gives 1.5W per channel into 32 ohms and Musical Fidelity specifies 16 ohms as the minimum load, which covers most full-size headphones.

Does it decode MQA?

Yes, in hardware, on all of the S/PDIF and AES/EBU inputs as well as USB. It is also Roon Tested.

What are the digital filters for?

Seven filter settings plus an oversampling-bypass mode change how the converter handles the top octave. Pick by ear; nothing is permanent.

See It in Action

audio-2g looks over the M6x DAC and its connections:

hxos plus unboxes one and walks through the rear panel:

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Learn More

Want to learn more about DACs, digital filters, or running a system without a preamplifier? Visit our Learning Center for guides, tips, and expert advice.