MUSICAL FIDELITY M6xDAC 32 Bit Dual Mono DAC – A Milestone Instruction Manual
- June 4, 2024
- MUSICAL FIDELITY
Table of Contents
32 Bit Dual Mono DAC
Instruction Manual
Manual in different languages available from
www.musicalfidelity.com
*Manuals in other languages can be found on the Musical Fidelity website. Please navigate to the Downloads section of the M6x DAC product page to access them.
Introduction
Our M6x DAC is a new milestone in the history of Musical Fidelity DACs.
Its predecessor, the M6s DAC was one of the first to use the critically
acclaimed ESS 32-
bitHyperStream II DAC architecture. With theM6sR DAC, we continued to improve
the firmware and added a few other quality-of-life improvements. DSD was now
easier to use, we had full Roon Support, and in- & outputs were updated to
keep up with the fast-moving digital audio landscape. And the other big thing:
theM6sR DAC was now being made in the EU!
With the M6x DAC, we went even further. Building on our knowledge and
experience with are ESS chips, we upgraded them to the new ES9038Q2M, and now
use two of them in dual differential mode for a pristine dual-mono design. The
inclusion of a Time DomainJitter Eliminator results in superb SNR andTHD+N
performance with an unbelievably detailed transient response.
Other advances in the DAC section include upsampling and re-clocking.
Upsampling can independently be switched on or off.
The 16-core XMOS and CPLD MAX II Altera processors ensure there is always
enough headroom for these operations, the new digital filters, and the MQA
processing.
The single-ended RCA and balanced XLR outputs each have their own output
buffer. Via the XLR plugs, you can enjoy a fully-differential amplifier design
enabling a fully balanced output.
Both output stages deliver superior audio quality, and exhibit very low noise,
large output voltage swing, and high current drive. The excellent gain
bandwidth and very fast slew rate produce exceptionally low distortion.
The M6x DAC displays our continued development of our Super Silent Power
Transformers. Industrial grade power sockets with EMI filter and DC blocker
stop interferences and eliminate transformer hum. The encapsulated toroidal
transformer with low core saturation is ideal for audio applications and
especially perfect for digital audio due to its extremely low electromagnetic
radiation. Digital to analogue converters, compared to analogue amplifiers,
present their own design challenges. They work in different domains, have
their own requirements, and need to be treated as such. Power requirements are
unique, and solutions designed for amplifiers will not show similar results
when paired with digital circuitry.
We have always held circuit board design and layout up to the highest of
standards at Musical Fidelity. We are not believers of flashy board design
just for the sake of looks. The design & layout need to be custom-tailored to
each application, measure well, AND sound as envisioned. Only then have we
done our job. At this point, we have given the listener a palpable sense of
the recording venue that places the performers in a real-time holographic
space in their own homes.
Safety Information
This unit is supplied with a mains lead fitted with a moulded 13-amp plug. If,
for any reason, it is necessary to remove the plug, please remove the fuse
holder and dispose of the plug safely, out of reach of children. It must not
be plugged into a main outlet.
The wires in the mains lead supplied with this appliance are coloured in
accordance with the following code 
WARNING – This appliance MUST be earthed.
The colours of the wires of the mains lead of this appliance, may not
correspond with the coloured markings identifying the terminals in the plug,
proceed as follows:
- The wire which is coloured green and yellow must be connected to the terminal in the plug which is marked with the letter E or coloured green or green-and-yellow, or by the earth symbol:
- The wire which is coloured brown must be connected to the terminal which is marked with the letter L or coloured red.
- The wire which is coloured blue must be connected to the terminal which is marked with the letter N or coloured black.
- If connecting to a BS1363 plug, a 13-amp fuse must be used.
Precautions & User Information
WARNING: Any modifications to this product, not expressly approved by
Musical Fidelity, who is the party responsible for standards compliance could
void the user’s authority to operate this equipment.
This new M6x DAC is designed and built to provide trouble-free performance. As
with all electronic devices, it is necessary to observe a few precautions:
- Heed all warnings shown on the back of the product.
- Only connect the M6x DAC to a mains outlet having the same voltage as marked at the back of the unit.
- Always ensure that when disconnecting and reconnecting your audio equipment the mains supply is switched off.
- Position the mains’ lead and signal interconnects where they are not likely to be walked on or trapped by items placed on them.
- Do not use near water, or place water-filled containers on the M6x DAC, for example, a flower vase or potted plants. If water does spill inside, immediately pull out the mains plug from the wall socket and inform the dealer, who should then check the unit before further use. Entry of liquid into the M6x DAC is dangerous and may cause electric shock or fire hazard.
- Do not place the unit near direct heat sources such as radiators, direct sunlight or other equipment.
- Do not remove any covers or try to gain access to the inside. There are no user adjustments or fuses to change without qualification. Refer all service work to an authorized Musical Fidelity agent.
Note: Unauthorized opening of the equipment will invalidate any warranty
claim.
The electronics in modern hi-fi equipment are complex and may, therefore, be
adversely affected or damaged by lightning. For the protection of the audio
system during electrical storms, remove the main plugs. If after-sales service
is required, to help the dealer identify the M6x DAC please quote the serial
number located on the rear panel of the unit.
Installation
Introduction
This unit will deliver the ultimate performance possible from any digital
source. It is designed to upgrade CD players, TVs, set-top-boxes, DAB tuners,
USB Streamers and PCs Laptops and any other source providing a variety of
digital outputs.
Note: In normal operation, the unit dissipates a small quantity of power
at all times, and it is important that it is adequately ventilated. The
M6SRDAC must be protected from humidity – if the unit is moved from a cold
place to a warm room, leave the unit for an hour or so to allow sufficient
time for the moisture to evaporate.
Cleaning
Before cleaning the unit, switch off the power at the mains switch and remove
the mains plug from the wall socket. Clean the cabinet and remote-control unit
using a moist cloth. Using solvents, white spirit or thinners is not advised,
as they could damage the surface finish.
Installation
Position the M6x DAC on a stable, horizontal surface where there is no risk of
it being knocked or subjected to vibration such as from loudspeakers.
Power Connections
The M6x DAC is supplied with a standard IEC mains cable which plugs into the
IEC socket at the back of the unit.
Audio Output Connections
RCA audio outputs: Use good quality RCA phono audio cables (fully connected
signal and ground), for optimum signal transfer.
XLR audio outputs: Use good quality XLR audio cables (fully connected hot and
cold signals and ground), for absolute optimum signal transfer.
Digital Input connections
COAXIAL input: Connect RCA digital source to digital input RCA socket. Use a
good quality fully connected (signal and ground) coaxial digital cable, for
optimum signal transfer. OPTICAL inputs: Connect the optical digital source to
the optical input socket. Use a good quality “Toslink” cable, for optimum
signal transfer. USB input: Connect a computer or similar USB “host” source to
the USB input socket. Use a good quality USB 2.0 type cable (not supplied),
for optimum signal transfer. Try to keep the USB cable length to a minimum for
the best reliability. The USB standard maximum for a single cable is 5M, after
which repeaters (normally mains-powered USB hubs) are required. We do,
however; recommend avoiding such a setup if at all possible. AES/EBU input:
Connect a balanced AES/EBU source to the digital input XLR socket. Use a good
quality XLR cable, specifically designed to carry digital signals and not XLR
cables for analogue audio transmission!
Interconnects
Note: Musical Fidelity currently do not make any interconnecting cables
other than those supplied with the unit. Musical Fidelity does not endorse any
other manufacturer’s cables.
If necessary, please refer to the dealer who can advise on quality cables for
any particular setup.
Facilities & Connections
- Power/Standby/Mute button and LEDs
- IR Receiver
- Filter selection
- Reclock LED
- Input selection
- Output Selection
- PCM Sample rate LEDs
- DSD Rate LEDs
- MQA LED’s
- Volume Control
- Headphone Socket
- RCA Analogue output L/R
- XLR Balanced output L/R
- OPTICAL Digital inputs 1,2
- 230/110 V switch
- COAXIAL Digital input
- AES/EBU Balanced digital input
- USB Digital input
- Mains IEC socket
Standard XLR Balanced input/output lead connections:
(for reference only, no XLR signal leads supplied)
Pin functions:
- Ground, 0V
- Normal polarity (“hot” or “+”)
- Inverted polarity (“cold” or “-”)
Operation
Once the M6x DAC unit is correctly wired up and plugged into the mains, the
orange STBY led should be lit.
In this mode, the M6x DAC is consuming a minimal amount of power.
To switch the unit on, press the Power button (1) on the front of the unit.
The blue PWR indicator will light along with the red MUTE indicator. After a
few seconds, when it has stabilised, the MUTE function will switch off and
the unit is ready for use.
Input selection
The M6x DAC has a total of five inputs available. These are Optical 1 and
2, Coaxial, AES/EBU and also USB.
When the power cable is inserted into the Mains IECsocket 19 the Optical 1
input is selected by default.
When the M6x DAC is taken out of sleep mode, it will default to the last input
selected.
From the front panel, you can cycle through the inputs using the ◄ and ►
buttons (5). Pressing ► while the USB input will cycle back to Optical 1.
Whilst on Optical 1 the ◄ button will take you to the USB input again.
The remote control has direct access buttons for each input. Simply press the
appropriate button to move directly to that input.
When a valid signal is received on the selected input, an indicator in either
group 7, 8 or 9 will light to show you the incoming sample rate.
Optical and coaxial inputs
All optical and coaxial inputs are capable of accepting up to 24 bit 192
kHz PCM stereo datastreams and MQA data streams. The incoming data sample rate
is displayed on the front panel LEDs for reference.
Note: Indicators 7, 8 and 9 show the actual sample rate of the digital data
received by the M6x DAC. Some playback software may have altered this compared
to the original file.
USB Input
The USB input is capable of accepting up to 32-bit 768 kHz PCM, DSD 256
(native DSD 512) data streams and MQA data streams.
Computer settings for USB
A good quality USB 2.0 cable is required to connect the unit to the computer.
Normal USB standards stipulate that this should be 5M or less; and we
recommend keeping it as short as possible.
WARNING: Older USB cables are often heavy and bulky and must be supported
to avoid damage to the USB socket. Any physical damage caused to this socket
will not be covered by warranty.
The computer should now detect the M6x DAC. A driver installation is only
required on Windows.
- Linux kernel 2.6.33 or later (no driver required)
- Apple OS X® 10.6.4 or later (no driver required)
- Windows 10 Creators Edition or later (driver found on included CD or on Musical Fidelity website)
For playing native DSD on Windows a driver installation is required.
Any device that is compliant with the USB Audio Class 2.0 standard should also
operate with the M6x DAC. However Musical Fidelity are unable to provide
support for operation with anything other than the system listed above.
CD, MP3, WAV, AAC/+, OGG, FLAC, and any other audio file types played on
suitable playback the software will now play through the unit.
Note: This USB input has a high-speed serial data processor, and by its nature, requires a very high volume of USB bandwidth. It will benefit greatly from being the only device connected on its USB ‘bus’. Sharing the same bus with other devices could cause unwanted artefacts such as dropouts or temporary loss of signal. This especially includes the use of the unit on a USB hub/splitter whether alongside other USB components or not. A direct connection to the host computer by the shortest USB 2.0 lead possible is very much recommended.
Digital Oversampling FIR Filters
The digital oversampling FIR filters can be set with button 2 on the front
panel. For a detailed description of each filter see page 10.
Note: When playing MQA files, the user’s filter setting is not active, the MQA
filter is always used.
The MQA filter is a proprietary custom-made filter by MQA for our DAC to
ensure the best possible MQA experience.
During DSD playback, the DAC’s internal DSD filter is turned on and the
digital filters have no effect.
Filter 8 – Oversampling Bypass
Using filter setting 8, the oversampling FIR filter is bypassed, and the
source data is upsampled to 352,8kHz/384kHz on the XMOS chip and sourced
directly into the ESS 9038’s IIR filter.
Upsampling is automatically switched on when using filter 8 and it is not
possible to change the volume. Therefore, only filters 1-7 can be used when
VAR output is used. If you want to use upsampling, switch to FIX output
beforehand.
When filter 8 is set and you switch from FIX to VAR output, or when headphones
are connected, filter 8 is automatically switched to filter 1 so that the
output volume can be changed. When playing a PCM format with a sampling
frequency of 705.6 / 768kHz, filter 8 is automatically turned on (NOTE:
without up/downsampling to 352,8/384kHz), which turns off all remaining
filtering, improving audio parameters and the frequency spectrum by yet
another step.
Reclock
Reclocking synchronizes digital audio signals with the master clock in the M6x
DAC. This feature is always on for all inputs and ensures best audio
performance at all times.
Upsampling
For incoming PCM signals, upsampling can be turned on or off with button 4 on
the front panel. When turned on, incoming PCM data up to 192kHzsample rate is
resampled to the sampling frequency of 352,8kHz or 384kHz according to the
original multiple of the sampling frequency.
Note: Upsampling is automatically turned on for filter 8 for sample rates
between 44.1 and 192 kHz.
MQA (Master Quality Authenticated)
The M6x DAC includes MQA technology which enables you to play MQA audio files
and deliver the sound of the original master recording. Visit
mqa.co.uk for more information.
MQA Indicators:
MQA – Green LED – indicates that the product is decoding and playing an MQA
stream or file, and denotes provenance to ensure that the sound is identical
to that of the source material.
MQA Studio – Blue LED – indicates it is playing an MQA Studio file, which has
either been approved in the studio by the artist/producer or has been verified
by the copyright owner.
OFS – Magenta LED – (Original Frequency Spectrum) confirms that the product is
receiving an MQA stream or file which is already decoded. This delivers the
final unfold of the MQA file delivered by services like TIDAL or media players
like Roon.
Outputs
On the rear of the unit are 2 sets of outputs. RCA (single-ended) and XLR
(balanced). You can connect the M6x DAC to your amplifier using whichever is
more convenient.
FIX/VAR Switching
The outputs can operate as either fixed or variable mode. Fixed mode is
suitable for connection to other equipment which offers volume control.
Variable mode allows connection directly to power amplifiers or active
speakers where the M6x DAC provides the volume control.
Choosing between these settings is done by using button 6 on the front panel.
Keep the button pressed for 2 seconds to switch between FIX and VAR output.
Headphones
The M6x DAC also includes a high quality headphone amplifier. Connecting
headphones to socket 11 will automatically mute the main outputs. The volume
control on the front panel 10 or the remote control now adjusts the volume
sent to the headphones.
sent to the headphones.
Note: When headphones are connected with the output set to FIX, the
output automatically switches to VAR and the volume level is set to 40dB.
When headphones are connected with the output set to VAR and the volume level
is greater than -40dB, the -40dB level is automatically set for a safe volume
in the headphones. The volume level on the VAR output without headphones
connected is remembered by the device even after it has been switched off.
With headphones connected, the device will remember the volume level if it is
less than -40dB and only until it is switched off.
Remote Control Handset
The remote control shown below enables functions from this and other units
from the M3, M5 and M6 ranges to be operated from a convenient distance.
The remote control buttons are split into 3 distinct areas.
The three rows of grey buttons at the bottom are used to control the M6SRDAC
and are detailed below.
The blue buttons control an amplifier such as the M6si. Consult the amplifier
manual for more information.
The remaining grey buttons located in the upper section control a CD player
such as M6scd. Consult the CD player manual for more information.
As the handset uses an invisible infra-red light beam, the front edge must be
pointed directly towards the receiver window at the front of the player,
without visual obstruction between them. If the range of the remote control
greatly decreases, replace the batteries with new ones.
Do not mix old and new batteries – two are required, size AAA, LR03 or SUM-4.
Please dispose of used batteries in accordance with local battery disposal
regulations.
OPTICAL 1 selects OPTICAL input 1
OPTICAL 2 selects OPTICAL input 2
COAX selects COAXIAL input
AES/EBU selects balanced AES/EBU input
USB selects USB input
STBY switch the M6SRDAC between standby and operating mode
UPSAMPLE enables or disables upsampling
FILTER selects a digital filter
VOLUME ▼▲ controls the main output of M6SRDAC in variable mode or headphone
level when connected.
Digital Filters
The M6x DAC allows for detailed tuning of the audio experience. It comes with
multiple preset reconstruction filters built-in. Musical purists can simply
unpack the M6x DAC, carefully cable it up, just leave it at its standard
settings and feel the immediate musical integration: the whole sound is sweet
and clear; the treble is completely grain free and extended. The bottom end
sounds endless with tactile bass dynamics.
As you get reintroduced to your music library, you might, at some point, want
to discover what else is possible and hear it from different stages. It is
then when the customizability and settings turn the M6x DAC into a powerful
tool for experts, which elevates it into a league of its own. Explore the
sound stage with upsampling or without and see if you are drawn in deeper.
Choose between the different digital filters and tailor the sound reproduction
to your specific liking or to your specific setup. In a way the M6x DAC can be
used like a professional tool for the experienced user:
- Linear phase fast roll-off – Most common filter with clean overall suppression and excellent rejection, best for music with large transients. Provides crisp clean highs.
- Linear phase slow roll-off – Low group delay – and symmetrical input response. Less ringing than linear-phase fast roll-off. Punchier bass than LPFR, with clean highs.
- Minimum phase fast roll-off – Minimal pre-ringing, preferred for imaging and soundstage. No aliasing in the frequency domain. Stronger bass than linear-phase, clean highs.
- Minimum phase slow roll-off – Non-symmetrical filter designed to minimize pre-ringing. Strong punchy bass with good transient attacks.
- Apodizing fast roll-off – A version of the linear-phase fast roll-off filter optimized to improve pre-ringing.
- Hybrid fast roll-off – A combination of linear phase and minimum phase. Fast transient attack, strong punchy bass, crisp highs.
- Brick wall – One of the earliest designs, intended for the highest suppression possible, with high delay and pre-ringing. Linear-phase, crisp clean highs.
- Oversampling bypass – The oversampling FIR filter, used for the 7 above-mentioned presets, is bypassed and source data is upsampled to 352,8kHz/384kHz on the XMOS chip and sourced directly into the ES9038Q2M IIR filter. Bypassing the oversampling filter reduces the on-chip PSU / ground noise and consequently reduces signal-correlated clock modulation on the ESS DAC’s silicon die. When the source data is 705.6 / 768kHz, filter 8 is automatically turned on (NOTE: without up/downsampling to 352,8/384kHz), which turns off all remaining filtering, improving audio parameters and the frequency spectrum by yet another step.
Troubleshooting
| Problem | Probable Cause | Remedy |
|---|---|---|
| No power. | The power plug is not inserted into the socket correctly. | Plug in |
securely into unit’s IEC socket.
The excessive hum from system speakers.| The audio connector plug is not fully
pushed in. Cable Fault. Unsuitable Cable (e.g. cable grounds not connected).|
Insert plug securely. Check the cable is connected at both ends. Some
“esoteric” cables have internal wiring intentionally disconnected/modified.
For best results on all inputs, please use a good quality screened coax signal
and screen directly connected to both ends.
Digital input not working.| No connection to that input. Incorrect input
selected. Wrong data type sent to DAC.| Check connection and cable. Select the
correct input Check source digital output is set for “16-bit stereo PCM” or
similar. This particularly applies to some TVs, most DVD players, and other
home theatre-type devices that may give a multichannel digital output. Refer
to the source’s manual for further information.
No audio output. or too low-level output.| Incorrect or missing
connections. USB Driver not selected.| Check connections and make sure they
are secure. See the Musical Fidelity website for relevant OS setup
information.
Dropouts in sound.| Digital input leads are not properly connected.
Faulty digital input lead. Faulty optical lead.| Check input lead is fully
secured. Change lead. Please use a good quality straight-through signal-and-
ground phono to phono lead. Optical lead breakage. This can occur if the
optical lead is bent into a radius too small. Avoid tight corners in routing
optical leads.
No audio output from USB input.| USB Cable is not connected. M6 USB Driver not
selected.| Check connections and make sure they are secure. See the software
section for relevant OS setup information.
Please check device is listed in the device manager (Windows®) or in the
Sound, audio devices for MAC OS X.
Make sure the Musical Fidelity USB audio device is selected as the default
OUTPUT device.
Check USB port functions with another device.
Not detected when connected to USB.| USB Cable is faulty. USB not working/
enabled on the computer. Correct USB drivers are not installed.| Check and
replace the cable.
Check USB port functions with another device.
Download and install the device driver from the software downloads section on
the Musical Fidelity website.
Dropouts in sound (USB input).| Shared USB port with another device. The
computer is busy with another application.
Computer low on resources.| Avoid sharing the USB port with other devices. if
possible.
At times an application (program) may intervene, sometimes invisibly e.g. a
virus scanner. When this happens, computer resources are temporarily used up,
and playback may suffer. This is not a fault. Try running fewer applications
if possible.
Technical Specifications
Output (RCA/XLR)
Output impedance
Output, digital OdB level| < 10 ohms
RCA 2V RMS, XLR 4V RMS
---|---
Headphones
Power
Output impedance THD
Signal/Noise ratio Frequency response| 1.5W / 32 ohms
< 5 ohms
< 0.005% at 1kHz @ OdBFS
115dB „A”-wt.@ OdBFS
+0,1dB at 20Hz, -0,4dB at 20kHz
DAC
DAC circuit
Total correlated jitter Linearity
Frequency response
Channel separation
Signal to noise
Total harmonic distortion| 2x ES9038Q2M (dual mono) with 8x digital filter 32 bit Hyperstream II
<12 picoseconds peak to peak
<0.4dB down to -130dB
-0,1dB at 10Hz, 0dB at 1kHz, -0,4dB at 20kHz < -130dB at 10kHz @ OdBFS
120dB „A”-wt. at 1kHz @ OdBFS
< 0,0005% at 1kHz @ OdBFS
Connections Line level outputs
Digital inputs| 1 pair line level RCA (phono), left and right
1 pair line level XLR (balanced), left and right
1 RCA coaxial SPDIF in (up to 24bit/192kHz stereo PCM)
2 TOSLINK optical in (up to 24bit/192kHz stereo PCM)
1 AES/EBU balanced digital in (up to 24bit/192kHz stereo PCM)
1 USB 2.0 in for computer/PDA/other “host” (up to 32bit/768kHz stereo PCM, DSD256 DoP, DSD512 native), fully asynchronous
(Actual data determined by source file/computer software settings)
Power requirement Mains voltages
Consumption| 110 – 230 V
max. 20W, <0,5W in standby
Weight
Unit only, unboxed
In shipping carton & inc. accessories| 6.9 kg ca. 10.3 kg
Unit dimensions
Wide
High, including feet
cDeep (front to back) including terminals| 440 mm 100 mm 390 mm
Musical Fidelity reserves the right to make improvements that may result in
specification or feature changes without notice. E&OE. Microsoft and Windows®
are either registered trademarks or trademarks of Microsoft Corporation in the
United States and/or other countries. Mac and Mac OS are trademarks of Apple
Inc., registered in the U.S. and other countries All other trademarks used
herein are the property of their respective owners.
MQA and the Sound Wave Device have registered trademarks of MQA Limited © 2016
Item Disposal Information for Europe
DISPOSAL
The crossed-out wheeled bin label that appears on the back panel of the
product indicates that the product must not be disposed of as normal household
waste. To prevent possible harm to the environment please separate the product
from other waste to ensure that it can be recycled in an environmentally safe
manner. Please contact your local government office or your retailer for
available collection facilities.
a Division of Audio Tuning
Vertriebs GmbH
Margaretenstrasse 98
A-1050 Vienna
AUSTRIA
+43 1 544 858 0400
http://www.musicalfidelity.com
References
- Homepage | Experience the best sound with MQA | MQA
- Musical Fidelity | World-Class Manufacturer of Award Winning Amplifiers, CD Players, DACs and Digital Audio Devices
- Musical Fidelity | World-Class Manufacturer of Award Winning Amplifiers, CD Players, DACs and Digital Audio Devices