iBasso AMP19
The iBasso AMP19 is a replaceable amplifier module for the DX340 and combines a Korg/Noritake Nutube 6P1 with a powerful discrete Super Class A amplifier. This gives the AMP19 two different output modes, each with its own sonic character. In Tube Mode, the Nutube delivers a warm, natural and slightly analogue presentation, while Super Class A Mode focuses on a powerful, dynamic and highly direct sound.
The Nutube 6P1 is a sixth-generation triode vacuum tube developed by Korg and Noritake. Unlike traditional vacuum tubes, the Nutube is significantly more compact and energy-efficient while retaining the characteristic properties of tube amplification. It has a lifespan of more than 30,000 hours and, according to iBasso, consumes only around 2% of the power of traditional vacuum tubes.
In Tube Mode, the Nutube 6P1 is used as a preamplifier tube. The tube adds harmonic richness to the sound, resulting in a warmer and more relaxed presentation. Vocals and instruments gain a softer texture and a natural, analogue character. The Nutube is suspended in a special PORON construction that absorbs vibrations and helps reduce microphonics.
Super Class A Mode uses 20 dual transistors to create a fully discrete amplifier circuit. The amplifier can deliver up to 2 amperes of current, providing ample current reserves for powerful dynamics, fast transients and a full, energetic presentation. With a single AMP19, you can therefore easily choose between the characteristic sound of Nutube and the powerful presentation of Super Class A.
For demanding headphones, the AMP19 can also be connected to an external 12V DC power supply. This increases the amplifier's power supply voltage from ±6.5V to ±12V, allowing the balanced 4.4mm output to deliver up to 2150mW + 2150mW at 32 ohms. Without an external power supply, the maximum output power in Super Class A Mode is 1000mW + 1000mW at 32 ohms. In Tube Mode, the AMP19 delivers up to 1850mW + 1850mW at 32 ohms when connected to an external power supply.
In Tube Mode, the AMP19 uses a JRC hardware volume control with 100 steps. The volume is adjusted using an analogue method, keeping the original DAC signal intact and avoiding digital attenuation. This also helps reduce noise at low volume levels and allows precise volume adjustment for both sensitive IEMs and demanding headphones.
Every AMP19 is tested before shipment using an Audio Precision APx555 audio analyzer. The Nutube 6P1 is then manually calibrated and matched to ensure consistent operation and sound.
The AMP19 features both a balanced 4.4mm and a single-ended 3.5mm headphone output. The frequency response ranges from 10Hz to 40kHz (±1dB), while the output impedance is 1.4 ohms via the 4.4mm output and 0.7 ohms via the 3.5mm output.
The iBasso AMP19 makes the DX340 a more versatile system with two distinctly different amplifier characteristics. Those who prefer the warm and harmonically rich presentation of Nutube can use Tube Mode, while Super Class A Mode offers maximum dynamics and powerful headphone drive. The DX340 must be equipped with suitable firmware to use the AMP19; the current V1.09 firmware supports the AMP19.
