6th-gen Korg Nutube
A triode tube stage for rich overtones and smooth sound.
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Nutube warmth for your DX300 or DX320.
A hand-tested Nutube amp card for the iBasso DX300 and DX320, with 4.4mm balanced PO and LO outputs.
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MEET THE AMP14
A hand-tested Nutube amp card for the iBasso DX300 and DX320, with 4.4mm balanced PO and LO outputs.
A triode tube stage for rich overtones and smooth sound.
A Toshiba JFET buffer, separate grounds and a low-noise volume controller.
Each module is tested and calibrated at the factory.
The iBasso AMP14 is a plug-in amplifier card that brings the sound of a sixth-generation Korg Nutube to iBasso’s DX300 and DX320 players, with two Pentaconn 4.4mm balanced outputs: a headphone output at up to 5.2Vrms and a line output at 1.8Vrms. Each card is hand-tested and calibrated at the factory.

Made by Korg and Noritake, the Nutube works exactly like a conventional triode vacuum tube, with the same rich overtones sought after in triodes, while using far less power and space. In the AMP14 it handles voltage amplification, for an engaging, unique tube sound with excellent linearity.

After the Nutube 6P1 voltage amplifier, a JFET differential converter creates the L−, L+, R+ and R− signals. Two JRC volume chips form a four-channel, truly balanced volume control, and a four-channel balanced buffer drives the outputs. Pentaconn 4.4mm sockets give excellent sound quality and durability.


The AMP14 feeds the signal to the Nutube’s cathode, whose impedance is lower than the grid’s, reducing interference from outside sources for an excellent noise floor, low Wi-Fi interference when streaming, and well-controlled tube microphonics.

The amp section of the DX300 and DX320 has its own battery, ideal for a card with strict power requirements. Two Linear Technology DC-DC chips provide four supplies: 3.6V for the cathode through a low-noise LDO, 14V for the Nutube’s anode, and +8V and −8V for a 16V swing for the op-amps.


Every AMP14 is tested and matched on an Audio Precision analyser, with three multi-turn potentiometers on the board calibrated by hand for the Nutube’s best performance, for a clean, extended treble and a sweet, engaging sound.


| Tube | Korg Nutube 6P1 (6th generation), cathode input · Toshiba 2SK209 buffer |
|---|---|
| Outputs | 4.4mm balanced headphone (5.2Vrms) · 4.4mm balanced line out (1.8Vrms) · Pentaconn sockets |
| Circuit | JFET differential converter · 2 × JRC volume (4-channel balanced) · 4-channel balanced buffer |
| Power | From the player’s amp battery · 4 DC-DC supplies (3.6V, 14V, ±8V) |
| Compatibility | iBasso DX300 and DX320 |

THE FINER DETAILS
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Specifications are based on manufacturer information and may change.
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Every UK order has a free delivery option, and orders of £50 or more qualify for free next day delivery. Order by 12 noon, Monday to Friday, for next day delivery; orders placed after 12 noon, at the weekend or on a bank holiday are dispatched on the next working day. Stock availability and destination also affect arrival — check the options shown at checkout.
Pre-orders ship when stock arrives; the next day service starts after dispatch. Full delivery information
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