Mason FuSang is configured with 12 Balanced Armature drivers and a dBC-s Dual Side Bone Conduction System. UM used custom-made large-size BA drivers which have significant advantages in soundstage size and distortion control. The bone conduction system contributes to the full range refinement by adding weight and density to the sound. This guarantees that the Mason Fabled Sound can deliver an extraordinarily natural and realistic sound.
PHAntasy is the first member of our Portable Headphone Amplifier (PHA) series. When we kicked off the development of PHAntasy, we determined to achieve two major goals; One is to preserve the true spirit and performance of SET amplifier, pure class-A, transformer coupled output and most important of all, sensational music presentation as we ever experienced on best SET amplifier, and the other is true portability with rechargeable battery via 5V USB port. We examined every detail of SET topology and audition every possible valve candidate and come up with JAN6286, a military grade directly heated triode (DHT). We examined the topology and each element of the amplifier – JAN6286 tubes, boost converter, filament supply, Battery configuration, and Passive Components - to find the best sounding components and combination. As we put them all together we ended up with The PHAntasy, a true fantasy to audiophiles.
At the center of PHAntasy are a pair of JAN6286 valves, each one is soldered on the board and responsible for major amplification of each channel. They are well damped on the PCB and the whole enclosure provides solid chassis to isolate them from external vibration that causes microphonics.
A triode is unique as gain device that tends to generate more even harmonics than odd ones if any. The result is music sounds airy, smooth, and natural than other type of devices. JAN6286, a directly heated triode, instantly enters working condition after power on and provides intimacy and lifelike sound stage more than none filament type triode.
There is the only current buffer between JAN6286 and the output transformer. The buffer is highly linear and has extremely low distortion that adds nothing but driving current. All circuitry is running in pure Class-A mode. JAN6286 designed for military purposes and driven by smart filament bias inherently has an ultimately extensive lifespan. There is no obvious degradation of tube performance for 10 years of usage.
PHAntasy is a masterpiece loyal to the original spirit of SET amplifier. Its output transformer is the last mile in delivering music energy to headphones. The bandwidth, dynamics, distortion, and maximum output power are limited by this iron core. No matter how well active circuitry performs, a worse transformer will choke them all. The output transformer might be the only component that spent more effort than the tube in design process. The nickel core and multiple winding transformer is a custom version dedicated for PHAntasy. Unlike home stereo SET dealing with only 16,8,4-ohm loudspeakers, PHAntasy is dealing with headphones’ impedance from 600 down to 30 ohm that complicates things even more. A choice of nickel core is to ensure widest bandwidth and minimal size for portability, otherwise, the transformer will be triple its size and weight. A multiple secondary windings are wisdom to cope with the widest impedance range instead of traditional single winding multiple taps.
PHAntasy is a pure analog and full discrete amplifier. A frequently asked question is why we dare to reverse the trend of integrated DAC. The answer lies in our belief that SET amp is simple and beautiful. We can only make it best instead of adding an average DAC. An amplifier shall explore the full potential of headphone and gives user the freedom to formulate his/her own recipe like what we did in top-notch stereo system. The fact is that even using mobile or tablet as source playing CD-quality music, PHAntasy delivers warm and detailed music on lifelike sound stage you ever experienced.