In 1877, Edison invented a kind of recording installment which recorded 8 seconds sounds for the first time in the world.
In 1977, Germany inventor Andreas Pawell applied for the patent in the name of the system of portable record which downsize the large stereo and replay a living voice.
In 1997, the South Korean Moon and Hwang invented the portable MP3 Player and applied for the relevant patent.
……
In 2010, Steven Wan and his team of acoustic fans from China combined the portable player with the HIFI stereo and created the first Pocket HIFI whose SNR is up to 108 dB and can play the audio files of 24 bit/192 KHz SR perfectly in the world.
The three world first of Pocket HIFI
The first portable player can play the audio files of 24 bit/192 KHz.
The first portable player whose jitter less than 5 picoseconds.
The first portable player can promote a 300 ohm earphone.
Regius walnut: black walnut in North America
The outer casing material of the Pocket HIFI C4 player is made of the black walnut in North America. The black walnut had been called regius walnut. The pleasant vignette is formed by the clear, smooth glossy and wavelike grains and the clear annual ring. It provides each music fan a unique player.
Precision: it is manufactured manually.
Wan’s team adopted to process the wood by the CNC numerically-controlled machine in the constant temperature and humidity workshop. The design and the special curve on the wood were engraved manually.
Be made manually in the environment of the constant temperature and humidity.
The successful output of the excellent 24bit/192KHz sound quality was largely attributed to the famous single HIFI CHIP inside, such as the DAC (Digital-to-Analog Converter ) . WAN’s team chose the CS4398, a top DAC chip from CIRRUS Logic. It produced quite satisfying quality with a dynamic range up to 120dB, as well as an extremely high decoding performance to decode the 24bit/192KH format.
·ADI AD823 chip
·CIRRUS LOGIC CS4398 DAC chip
·CIRRUS LOGIC CS8422 SRC chip
·TCXO high-precision crystal Oscillators
A nostalgic stem for adjusting the volume
We used the flagship series “pro-audio series” of the famous ALPS volume potentiometer in Japan. The dust cover and grounding connection were ordered according to the specifications of the Pocket HIFI player. The rate of the volume error was lower than 5% in average after 1,000 hours’ text. The volume error rates of the HIFI player was15% lower than the ALPS official data.
Aim to broadcast the audio of HIFI level fro a portable player the size of a cigarette pack, the assembly such as circuit board, chip, even the capacitor must be selected carefully.
The traditional player used the signal chip whose main structure was made of MPU, DAC and earphone amplifier. This structure always processed the audio at the cost of great loss. This kind of voice sounded stiff, rigid and apathetic. It could make your ears feel tired, if you heard it for a long time. The internal structure of the Pocket HIFI player was much more complex than traditional MP3 player. In the Pocket HIFI player, the original audio must pass through 8 units from input to output for the sake of getting the perfect voice. Please look at the reference chart as follows:
Interior structures of the Pocket HIFI
Jitter Kill
On the basic of top material and the complex unit designs, the structures which were made of by C4 clock generator, TCXO high-precision crystal Oscillators and the CS8422 SRC chip of CIRRUS output the unbelievable rate of jitter which was lower than 5ps.On month day of year, the technique of circuit named Jitter Kill was registered as a patent for the other special technique of the Pocket HIFI player.
- Set the SRC manually
- ADI AD823 chip
- CIRRUS LOGIC CS4398 DAC chip
- CIRRUS LOGIC CS8422 SRC chip
- 3.7 V battery, SNR up to 108 Db, THD lowers than 0.003%
- The precision of 0805 resistance is up to 1% in the simulation
- Black 3U PCB
- 3U Gilt RCA interface for SPDIF IN/OUT (top grade)
- 3U Gilt interface for 6.3mm earphone (top grade)
- The rate of the Jitter is lower than 5ps
