DXC2.2 MKII digital to analog converter

MODELS

SPECIFICATIONS

TESTIMONIALS

REVISIONS

"the converter that has changed the relations between the purists and digital audio".  

 

The 768kHz DAC: 4x the limit of Blu-ray and 8x the equivalent of SACD!

> DXC2.2 MKII is ultra high performance, universal, future proof yet clean and simple to use.

> MCLK3 locking mechanism is JMF Audio’s smart answer to clocking issues with transports. 

> USB module permits bit-perfect operation with isolation and local synchronization! 

> DA768 conversion rates of 705.6 and 768kHz allows PCM audio to outperform DSD (SACD)!

> DMSS super symmetrical conversion on gold plated substrate is precision analog piece of art!

> Using a standardized link, MCLK3 extracts an incredibly detailed and natural sound! 

The main digital audio board handles the standardized audio inputs SPDIF and professional AES-EBU, and also receives the USB module as an add-on. It also embeds the reference master clocks. Because JMF Audio believes that digital electronics in an audio converter is all a matter of analog design (clocks are analog components by nature), great care was taken in the development of this new main digital audio board incorporating many innovative features. The two SPDIF and two AES-EBU audio standard inputs are independent and galvanically isolated. The clock and data recovery from the audio source is performed by the newly designed proprietary MCLK3 vari-speed 3-stage-locking mechanism that takes reference from the local master clocks through the MCDC master clock distribution circuits. 
The MCDC feature two shielded master clocks which are made-to-measure for JMF Audio. One is used as reference for input sampling rates multiple of 44.1kHz and the other is used for sampling rates multiple of 48 kHz. The implementation of the key concepts presented above has resulted in the printed circuit board design itself to be a work of art.

 

> Unrivaled precision timing!  High resolution is nothing without perfect timing.


The MCLK3 principle contributes to the absence of granularity, the natural wide open sound, the dynamics and “analog” feel that one can enjoy with the DXC2.2 MKII. The best sound quality is assured with a SPDIF or AES-EBU connection, with no fancy!

 
It has to be noted that the 176.4 and 192kHz sampling rates are supported over a standard single wire SPDIF or AES-EBU connection, whereas some professional DACs require uncommon or dual wire connections.

 

*The JMF Audio DMT 3.7 transport plays SACD and Blu-ray Pure Audio discs (192kHz), PCM and DSD files and connects to the DXC2.2-MKII using an AES-EBU interface. 

> The DXC2.2 MKII's USB module offers the highest quality way to enjoy files from your computer!

The USB module allows the connection of an audio server, typically a personal computer on which an audio software player has been installed*. As explained in the previous paragraph, the USB module is an add-on to the main digital audio board. The USB module is extractible from the chassis, which makes the DXC2.2 MKII open to potential upgrades to follow future computer audio interface standards. 

In order to make the DXC2.2 MKII immune to the electromagnetic interferences that could come from the computer via the USB link, the USB module features a galvanic isolation. There is no physical link between the computer and the audio circuits. Moreover the USB module is enclosed in an aluminum shield case to prevent any radiation. The USB module is powered by the DXC2.2 MKII through a dedicated power supply.

The data over the USB interface are transferred by packets, as opposed to SPDIF and AES-EBU interfaces that carry data continuously. The USB module of the DXC2.2 MKII hence operates asynchronously with the computer for the highest quality audio. The main digital audio board’s master clocks are the timing references and the USB communication is bidirectional. The DXC2.2 MKII’s USB module requests samples from the computer and provides them continuously to the main digital audio board at the local precision master clock’s rate. The DXC2.2 MKII is master over the USB interface.

The USB audio module is clocked by the master clocks through the MCDC master clocks distribution circuits described in the previous paragraph. One reference clock is used for the audio inputs multiple of 44.1kHz (44.1, 88.2, 176.4) and another is used for the inputs multiple of 48 kHz (48, 96, 192).
The USB module can operate in Audio Class 1 and 2, selected at the back of the device. 
Audio Class 2 is for performance (plug and play on MAC computers, with provided driver for Windows computers).

> DA768 conversion rates of 705.6 and 768kHz allows PCM audio to outperform DSD (SACD)!

The new digital to analog conversion board named DA768 converts zeros and ones to physical magnitude with the highest precision for the best musicality. The DA768 certainly is the center piece of the DXC2.2 MKII. The printed circuit board is a multilayer design featuring the PGP gold plating finish developed by JMF Audio in the early 90’s. This special finish requires all the components to be mounted and soldered by hand by our specialist. Given the components’ fine pitch, this work is similar to jewelry and watchmaking. 

The typical JMF Audio power supply design was improved on this new DA768 board to present an unprecedented stability. 

The audio data provided by the main digital audio board described previously are oversampled to rates as high as 705.6kHz or 768kHz depending on the input, whereas the other high-end DACs on the market convert at 192kHz maximum for the great majority and at 384kHz for a few others. 
The higher conversion rates have two benefits: the DA768 employs a non-destructive sampling image rejection digital filter and features the purest post-conversion analog stage. This makes a big difference on the perceived sound quality.

> DMSS super symmetrical conversion on gold plated substrate is precision analog piece of art!

The DA768’s DMSS (Dual-Mono Super Symmetrical) precision conversion stage backed with ultra high precision analog circuitry ensures unparalleled conversion linearity. The lowest level information that represent the slightest nuances in the performers’ play and the most subtle ambiances are perfectly extracted and correlated to the main musical content, which results in extraordinary sound homogeneity.

The DA768 features a volume control in the digital domain so the DXC2.2 MKII can be directly connected to a power amplifier. On the analog section, the new DA768 embeds a passive level attenuator which is remotely controlled by the HIGH/LOW switch at the back of the device. The output level range can then be adjusted according to the driven devices’ sensitivity. And, when the DXC2.2 MKII is used with variable volume control, setting the output level attenuation permits to turn the volume up and thus to optimize the conversion resolution and signal to noise ratio. 

Although super symmetrical by design, the DA768 includes a final unbalancing stage for the single ended outputs. Both single ended (RCA) and balanced (XLR) outputs feature high output drive capability to actually drive the modulation cables. The balanced XLR outputs are impedance matched with the JMF Audio modulation cables and with the PRS1.5 and HQS power amplifiers’ input stages for an increased three dimensional sound stage perception. 

> The DXC2.2 MKII was designed to be a timeless jewel!

After selection on technical aspects, refined selection on measurement, the final decision on absolutely all the audio components that the DXC2.2 MKII contains has been taken after long listening tests in the JMF Audio's studio. JMF Audio’s research and development investment in the remake (MKII) of the DAC series lasted over one year, with a total dedication and the will to make the best the smart way. Again, precision means Musicality!

 

 

Some DACs offer numerous possibilities. The JMF Audio DAC offers the best sound and upgradability.

 

Features:

SPDIF inputs 2  (IN1, IN2)
AES-EBU inputs 2  (IN3, IN4)
USB inputs 1  (IN0) 
Unbalanced output 1 stereo
Balanced output 1 stereo
Volume display  [30] to [99] in variable volume (no display in full-output)
Mode of operation variable volume / fixed full output (for use with preamp)
Source display [i0] to [i4]
Source selection, shortcut  quick toggling between USB and preferred SPDIF/AES 
Remote control IR remote control, all functions
Ground connection (earth) optional dia. 4mm banana type

Massive aluminum volume control button / double bearing / massive aluminum compartment / smooth rotation
Massive anodized aluminum chassis, mounted on special damped and anti skidding JMF Audio feet

Specifications:

 

Main digital audio board 
Input interface all inputs electrically independent / galvanic isolation
SPDIF inputs impedance, min. and max. level 75 ohms, 0.2V .. 5V
AES-EBU inputs impedance, min. and max. level 110 ohms, 0.2V .. 10Vpp differential
Clock recovery mechanism MCLK3 proprietary vari-speed 3-stage-locking mechanism with reference to the local master clocks
Clocking system master DAC concept with 2 made-to-measure ultra low jitter master clocks in MCDC proprietary clock circuits
Supported resolutions 16..24bits/ 32, 44.1, 48, 88.2, 96, 176.4, 192 kHz
De-emphasis de-emphasis 50/15us automatic, seemless
USB Module
Input interface entirely shielded module / galvanic isolation
USB connection type USB 2.0 High Speed compliant
USB Audio Class  Audio Class 1 or 2 selected with switch at the back
Synchronization  asynchronous, DAC master through MCDC clock circuits,
specific ASIO driver provided for Windows
Supported resolutions 16..24 bits / 44.1, 48, 88.2, 96, 176.4, 192 kHz
DAC section
Digital to analog conversion technology DA768 w/ DMSS topology on proprietary PGP multilayer gold plated substrate
True digital to analog conversion rate 705.6 kHz or 768.0 kHz depending on input 
Total harmonic distortion plus noise at full output 0.0008 % at 1kHz typical** (bw. 22Hz .. 22kHz)
True audio dynamics (EIAJ measurement) 130 dB typical** (real! no auto-mute function!)
True signal to noise ratio (full output, XLR) 130 dBA typical at 1kHz** (real! no auto-mute!)
Output impedance 50 ohms RCA and XLR
Output level range control passive attenuators, remotely controlled
Maximum output level

+20dBu (7Vp) XLR switch HIGH / 0dBu XLR sw. LOW

+14dBu (4Vp) RCA sw. HIGH / -5dBu RCA sw. LOW

Volume control 70 steps of 1dB, digital at the conversion stage
Main power supply
Mains voltage range 100..240VAC
Power supply isolation Two levels of electromagnetic shielding
Internal power supply distribution Proprietary QUAD-STAR-POWER 
Power consumption < 25W in operation (< 1W in standby)

**Dynamics and SNR measurements with 4th order low pass filter at 22kHz for accurate value. Measured performances with Audio Precision Dual Domain equipment. 

Important notice: Many modern DACs automatically activate an auto-mute function during supposed silences... Measures of SNR and dynamics may thus be impressive (incredible), but they do not reflect reality (music)... 

Characteristics are subject to change with product evolution, without notice.

 

Models:
DXC2.2-MKII Stereo unit Product described here
DXC6.10-MKII Modular: multichannel and/or DSP (PSL / PSL-X) See product page

Clients' comments:

Mr. Martin (HQS7001, PRS1.5, CM4, DXC2.2-MKII) former user of DCS with external clock:

"I plugged in the DXC2.2 MKII last Saturday and the listening is staggering. Same feeling as with the change of preamp. The mids are realy worthy of JMF Audio (French Musical Jewel) and the listening in general shows unequalled presence, fullness and sweetness. [...] The Mahler's 10th symphony played with my Kalista (CD transport) has reached a never imagined level of dynamics, sound stage and analog feel..."

 

Mr. D.H. (HPM500, HQS9001, PRS1.5, DXC2.2-MKII) former DXC version 1 owner, after comparison demo: 

"Great and clear improvement, superb sound stage and musicality (AES-EBU and USB), I look forward to receiving mine"

 

Mr. K.F. (HQS9001, PRS1.5, DXC2.2-MKII) Asia, hi-end audio equipment importer:

"Yes we have received the DXC2.2-MKII. The sound is amazing! We appreciate the ability to play 24bit/192kHz files as well as CDs through JMF Audio's technology."

 

Mr. J.D. (HQS6002, DXC2.2-MKII, CM4, DP2, PC3) France, JBL speakers, previously using Jeff Rowland, Wadia, Audioquest:

"I don't define myself as an audiophile since I don't listen to jazz or classical, but anyway, the difference [with my previous equipment] is stunning! I rediscover all my recordings... I have purchased a lot of new CDs and DVDs since! I also subscribed to an online music service [stream to the DAC] which made me discover talented artists, in hi-res!"

 

Mr. J-R (professional musician and producer):

"I only trusted vinyl records. I had never liked CDs. But with JMF Audio, there is no so-called 'digital sound'. It is extremely aired, lively, full. We were shocked..."

 

Mr. J.S (DXC2.2):

"I auditioned the DXC2.2 several years ago. The sound was really 'analog'. Unfortunately I could not afford it. So a dealer sold me the three unit MSB stack. It is good, it is precise, but there is not the life of the JMF. I finaly found a second hand unit when you released the MKII. Precision is one thing, but the DXC2.2 goes much further than that." 

After visit at JMF Audio: "We have the feeling that music is played slower, that the musicians are relaxed. [...] Today we listened to Music!"

 

Mr. Rinder (HQS2400, SR4, CM4, DXC2.2) on JBL speakers :

"The DAC is wonderful, so musical! It is strange but I feel like the musicians are in my living room"

 

Mr. Stephan (HQS6002, SR4, CM4, DXC2.2) :

"I never thought so much could be gained from digital"

 

Mr. Yu (HQS6002, PRS1.5, DXC2.2 MKII) Singapore, previously using Playback Designs source:

"Just want to let you know that I have received the unit [DXC2.2 MKII] yesterday and just completed the connection about three hours ago. Listened to the first piece of classical music and feel like I was transposed to the concert hall! Thank you. [...] .

 

Mr. Chan (DXC2.2 MKII), Hong Kong, 2015:

"I have to say thank you for your great and amazing DAC! Its performance is over my expectation... It is very natural, open and with very good resolution! Thank you very much again for your great product !!"  (e-mail feedback)

 

Mr. W.Ng., first owner of the DMT3.7 with DXC2.2-MKII combo in Hong-Kong (including DP5 AES-EBU cable):

"It was good to see you in Munich. The SACD/multi-disc player is absolutely impressive. When can mine be ready?" 

After reception:

"I must write to congratulate you guys for an amazing creation in the transport. Totally amazing. I now use it all the time from my array of other transports. Truly stunning." 

After a few months of experience:

"I own the dCS Vivaldi stack, Esoteric P01, CH Precision, 47Labs, Aurender W20, Sound Galleries Music Server, and I can tell you your source [DMT 3.7 transport and DXC2.2-MKII-C] is the best, by far. I play so many Blu-ray discs, it is now my most-used equipment."

 

 

...

 

 

Revisions on model MKII:
DXC 2.2 MKII -C Major upgrade. Power supplies and shieldings. Superb sound result. (2016)
DXC 2.2 MKII -B Improved power supply (AC side)

MKII does not mean a change of painting, it is a complete new design (chassis, boards, power supplies, features).  The device revision (B, C, D...) is indicated by a silver badge located on the rear panel. Please contact JMF Audio for the upgrade of your product. 

Previous models: (discontinued)

DXC 2.2 -C Improved power supplies and groundings
DXC 2.2 -B Improved power supplies
DXC 2.2  Initial release (2006)

 

© JMF Audio ®  1985-2017 - All rights reserved - Tous droits réservés

www.jmf-audio.com