iBasso Audio / AMP14BL

4.4mm compatible Nutube vacuum tube amplifier card for DX300/DX320. Compatible with 6th generation vacuum tube ""Nutube 6P1"", 4.4mm balanced connection.

■Uses 6th generation Nutube vacuum tube 6P1
・AMP14 uses the 6th generation Nutube6P1, which is ideal for portable products and has achieved significant power savings and miniaturization by applying Noritake Ise Electronics' fluorescent display tube technology. It has a longer lifespan of more than 30,000 hours compared to conventional vacuum tubes, and produces a warm and attractive sound with rich overtones unique to vacuum tubes.

■Circuit design in pursuit of innovation
1.JRC NJU72315 high performance audio volume
- Adopted dual ""NJU72315"" manufactured by JRC, which is known as a high-performance volume control with low noise and low distortion, to form an independent volume control hub. Noise attenuation processing can be performed at the same time when the volume is lowered, and the noise floor can be effectively suppressed even when operating at a lower volume. In order to achieve better sound, ""NJU72315"" is responsible for 2-way volume balance adjustment, and finally drives the headphones through a 4-way buffer.

2. GND separation processing to eliminate noise
- By separating the internal vacuum tube GND into signal GND and shield GND, the influence of noise generated by the common GND is effectively suppressed. In addition, in order to prevent noise interference between the vacuum tube amplification line and the rear line, a gold-plated custom inductor with internal resistance is used to isolate the signal GND of the vacuum tube amplification line and the analog GND of the entire device. In order to reduce the effects of vibration noise caused by mounting on the board, we did not mount the Nutube board, and instead used a cable that is flexible and resistant to vibration.

3.Toshiba 2SK209 field effect transistor
- Inherited from AMP9 and AMP13, which are known for their iBasso vacuum tube-based AMP cards, and continues to use Toshiba's field effect transistor ""2SK209"" as the binary signal output buffer. Furthermore, it is equipped with split loading technology to achieve four balanced outputs: L-, L+, R+, and R-.

4.NFB (negative feedback) circuit
・By configuring a negative feedback circuit, distortion is effectively reduced and a high dynamic range is ensured.

■4.4mm PHONE OUT+ 4.4mm LINE OUT
・AMP14 uses Nutube's voltage amplification method to achieve rich tones and a mellow listening experience with a 4.4mm balanced output. The 4.4mm connector part uses the industry standard Pentaconn 4.4mm connector part to ensure excellent acoustic performance and durability.
4.4mm PHONE OUT: 5.2 Vrms
4.4mm LINE OUT: 1.8Vrms

■Excellent noise control that does not interfere with tube sound
・The AMP14 vacuum tube uses a low impedance cathode input to reduce external interference and noise. With excellent noise control, you can experience pure vacuum tube sound.
*Noise may occur during data buffering in applications that require communication, such as streaming apps.

■New era 4.4mm balanced AMP card
・AMP14 uses two high-performance power supply chips from Syntek and is equipped with a total of four DC-DC converter circuits that supply 3.6V to the cathode and 14V to the anode. The DX320/DX300's ""dual battery design"" completely separates the batteries for the digital and analog parts, making it possible to use AMP cards with high power consumption such as AMP14 with stable operation and with limited board space.

■Manual matching that takes full advantage of Nutube's performance
- To maximize Nutube's performance, all AMP cards are tested with an audio analyzer and accurately matched by engineers. With AMP14, you can enjoy the sweet and moist sound unique to vacuum tubes, and the pleasant lingering sound with analog-like breadth and depth.
*AMP14 is compatible with DX320/DX300, but please update the firmware to the latest version when using it. ""

■4.4mm PHONE OUT: 5.2 Vrms
■4.4mm LINE OUT: 1.8 Vrms
■Accessories: Dedicated screwdriver for amplifier replacement, 2 types of dedicated screws (KM1.4, KM1.5), replacement cushion sheet, clear case for DX300/DX320, product warranty