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FX-Audio BL-Muse-02: a DAC with an aptX Bluetooth connection awarded with a Qobuzism!

These are not the most common devices, but digital-to-analog converters equipped with an aptX Bluetooth connection hold their own in terms of sound quality, and this using rather simple and cheap ways. Thus, a smartphone compatible with aptX Bluetooth and this FX-Audio BL-Muse 02 DAC are perfectly able to provide really good sound results when linked to a Hi-Fi system.

By Abigail Church | Testing Ground | September 15, 2017

Given its low speed and limited range, this DAC was not at all destined to broadcast audio files other than MP3. With a small receiver located close by, the Bluetooth connection has revealed itself to be, to everyone’s surprise, able to provide astounding sound performances, almost equaling CD quality. This is thanks to a compression process called aptX, using a very smart algorithm and not a kludge!

Mostly used thus far by professionals, the aptX appeared late in the mainstream Hi-Fi market, too late to be a challenger of lossless compressions like FLAC, which doesn’t cause storage problems anymore thanks to the increase of storage capacities, nor broadcast limitations thanks to Wi-Fi.

Despite all this, it’s not uncommon to find aptX Bluetooth modules included in USB DACs or in devices equipped with a DAC, but DACs working only with a Bluetooth connection are rare, at least in the field that concerns us, Hi-Fi, and we now invite you to discover a rarity, the FL-Muse-02 DAC from the Chinese brand FX-Audio.


The appearance of the FX-Audio BL-Muse-02 DAC, with its black anodized brushed aluminum box and its bar graph LED level meters located in the top part of its facade, is somewhat reminiscent of the look of car booster amplifiers, at a time when those were the fashionable car audio products.

As for the rest, the small pushbutton located in the lower part of the facade allows you, with a long press, to power the device On or Off, and with a short press to choose between the analog audio output or the coaxial or optical S/PDIF outputs, with a light indication from the corresponding blue LED. The red LED located atop of the pushbutton flickers while the device is not connected to another device broadcasting in Bluetooth, and remains fixed when the connection is established.

In the back are located the coaxial plug for the power pack, the RCA plugs for the analog stereo output, the coaxial and optical digital outputs and the Bluetooth antenna connector.


The electronic circuit board of the BL-Muse-02 DAC is well-equipped, but it’s far from the housing crisis as only the top side hosts components! Furthermore, for several of them, they are of traversing type chosen for their higher quality.

It’s in the active filtering of the decoded signals that these components are found in great numbers, such as 1% accuracy metal filmed resistors and dielectric plastic capacitors, used with a Texas Instruments NE5532 dual low noise operational amplifier.

The supply part is located under this filter, with two electromagnetic coils right when the tension arrives from the power pack blocking all high frequency parasitic signals. A 2200 μF/16V electrochemical capacitor filters the current and is followed by two regulators, a 78M05 for circuits running at +5V and a 78M09 generating a voltage of +9V, with which two circuits called static converters— ME7660C (MicroOne)—generate a voltage of -9V.

These ±9V voltages drive the NE5532 circuit, thus allowing it to work with 0V referenced signals, avoiding the use of coupling capacitors, especially at the output, which is beneficial to the bass frequency response and sound quality.

The Bluetooth receiver module is an nFore NF8670 equipped with a Qualcomm CSR8670 chip compatible with aptX. Signals are available in analog form, and pass through the active filter before going to the analog outputs, and also in S/PDIF form, formatted by a 74HC04 circuit before going to the coaxial and optical digital outputs.

A Toshiba TA7666 circuit, a 5 Step Logarithmic Dual LED Driver, drives the bar graph’s LEDs.


Once connected and installed on our PC equipped with an aptX Bluetooth receiver, the BL-Muse-02 DAC was automatically set up as the default soundcard, which means that when we opened the new Qobuz app, we were able to use it in aptX Bluetooth with this device. This is plug and play as we like it.

So, when we listen to Nelson Freire playing his Piano Works from Brahms, we get to listen to a piano rich of all its tessitura and dynamics, and not a caricature of a piano. We can even say that this is a very beautiful reproduction of this work presented by the FX-Audio BL-Muse-02 connected to our Sony UDA-1 amplifier driving our Triangle Antal Anniversary speakers.

We also listened to a few extracts from this work with Qobuz for Android on an aptX Asus smartphone, and we got the same sensations, but we had to delete the BL-Muse-02 from the PC’s Bluetooth peripherals to be able to connect it to our smartphone. Let’s continue in subtlety and richness of colors with this very beautiful symphonic poem Vysehrad that opens the cycle My Homeland from Smetana performed by the Malaysian Philharmonic Orchestra conducted by Claus Peter Flor. The harp chords at the beginning of this title are reproduced with finesse and without any acidity, and the full restitution of this symphonic poem allows you to enjoy completely and without effort its nuances, both in colors and in dynamics.

It also all goes very well with Claudio Capéo’s album Claudio Capéo, with a very good definition of the singer’s voice, as well as of the accordion accompaniment, while the bass foundations are making themselves heard when they have the chance, and this precision seems important. This is not the case with the title North Star from the album Tale Of Us, where the little FL-Muse-02 indulges with pleasure in the bass while preserving the (thin) sound message that gravitates around, as well as its details.

To conclude, for a very attractive price, with this FX-Audio BL-Muse-02 aptX Bluetooth DAC you can stream Qobuz from your PC or a smartphone compatible with aptX toward your Hi-Fi installation, close to the CD quality that Qobuz offers with its Hi-Fi subscription, thanks to the amazing aptX codec and the very high sound performances from this DAC to which we bestow a Qobuzism.

Manufacturer’s Website

We would like to thank Audiophonics for lending us the FX-Audio BL-Muse-02.

Playback Capabilities

- 16 bits at 44.1 kHz in near CD quality with the aptX codec


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