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Delivery time approx. 1-2 weeks
The story behind "M6 Double"
It all started with our fascination for the IN-12 Nixie tube.
Our first experiment was to use the IN-12 in a portable DAC/AMP, which led us to a bold idea: Could a smaller, refined Nixie tube be integrated into a portable device?
After extensive research, the team focused on the IN-17, the smallest Nixie tube ever made.
Since their invention in the 1950s, Nixie tubes have often been used in aerospace controls, stock market displays on Wall Street, and instruments in nuclear power plants. While larger tubes like the IN-12 are generally used in industry, the IN-17 is extremely rare and has a high collector's value.
For the M6 Double, the MUSE HiFi team collected over 2,200 IN-17 tubes across Europe over 12 months, starting in Russia. Of these, 2,100 units were reserved for production and 100 units were kept as spare parts for customer service.
Reviews
The World's First Portable Bluetooth DAC/Amplifier with Nixie Tube and Vacuum Tube
The M6 Double is the world's first portable Bluetooth DAC/amplifier equipped with miniature vacuum tubes JAN6418 – manufactured by Raytheon in the United States in 1974 and known as the smallest tubes suitable for portable devices – and IN-17 Nixie tubes produced in the 1960s in the former Soviet Union.
The World's Rarest and Smallest Nixie Tube
The Nixie tube was invented in the 1950s and was once widely used in aerospace controls, stock market displays on Wall Street, and nuclear power plant monitoring systems.
While the industry mostly uses larger tubes like the IN-12, the IN-17 is an extremely small and rare model with a very limited global supply. Over 12 months, the MUSE HiFi team procured and collected more than 2,200 IN-17 tubes from across Europe, starting from Russia. Of these, 2,100 are reserved for production and 100 are kept as spare parts for customer service.
According to our research, these 2,000 units represent almost the entire global stock of IN-17 tubes, making MUSE HiFi the world's largest single owner of IN-17 tubes. For this reason, the M6 Double is limited to only 1,000 units.
As the stock of Nixie tubes continues to dwindle, the IN-17 model is practically extinct. In some countries, it is almost impossible to find brand-new units. In the coming years, the two IN-17 tubes installed in each M6 Double are expected to have a collector's value far exceeding the device's price itself.
Unique Power Architecture Design
The Nixie tubes operate at 170 V, while the vacuum tubes run at an elevated 25 V. To achieve this, we developed a special 4500mAh battery and designed a secondary boost technology + split-current power supply circuit that independently powers the Nixie tubes at 170 V and the vacuum tubes at 25 V.
An MCU-controlled system drives the Nixie display via 20 MOSFET sets and seamlessly integrates HiFi performance with vacuum and Nixie tube technologies.
Additionally, the mainboard includes voltage regulation that effectively controls heat generation while ensuring stable voltage output for both circuits.
Core Chip Architecture
The M6 Double is based on ESS's flagship DAC platform and features a dual-architecture design specifically developed for integrating Nixie and vacuum tube circuits – the result of two years of meticulous development.
The flagship DAC chip ESS ES9039 has been extensively customized and features a special "Tube Mode" sound profile exclusively developed for the vacuum tube system. This not only enhances output performance in tube mode but also highlights the warm, rich mids and soft, delicate overtones of the JAN6418 tube – achieving performance comparable to traditional tube amplifiers.
At the same time, the output power has been improved at both the 3.5 mm single-ended and 4.4 mm balanced outputs, allowing the M6 Double to effortlessly drive high-impedance headphones.
Tube shock absorption technology
MUSE HiFi first developed and implemented an anti-vibration technology for vacuum tube installation in the M5, providing comprehensive damping to ensure stable current and pure sound.
This technology was further improved and refined in the M6 Double and now features a newly developed Nixie tube mounting system:
An independent sub-board was installed on the mainboard to precisely connect and secure the Nixie tubes, so they can be displayed at the exact intended angle.
Both the Nixie tubes and the display are located at the top of the device, allowing users to intuitively observe and operate the M6 Double.
Additionally, a comprehensive vibration isolation structure was developed for the JAN6418 vacuum tubes, including custom rubber damping components and a suspended mounting system. This provides full protection against mechanical vibrations, ensures stable current flow, and achieves the so-called "zero stethoscope effect" – for clearer, purer, and more refined sound reproduction.
Product specifications
- Model: M6 Double
- DAC chip: ES9039
- Bluetooth chip: QCC5125
- Supported codecs: LDAC / aptX
- Input: Type C 5 V 2 A
- Execution standard: GB4943.1-2011
- Dimensions: 121 mm × 81 mm × 24 mm
- Weight: ≈270 g
Scope of delivery
- M6 Double
- Charging cable
- Type C to Lighting
- Type C to Type C
- USB Plug
- Leather protective case
