NEW old stock!

Headphone amplifier kit - noble and compact at the same time

The HA-S is a headphone amplifier kit with a Nutube tube that guarantees outstanding sound quality anytime, anywhere. Even those who have not learned to use a soldering iron can assemble the HA-S independently and without much help. Let yourself be convinced by the pleasant, tube-based and warm sound.

Build your own headphone amplifier

The HA-S kit makes it easy to build your own headphone amplifier in just a few steps - and without the need for a soldering iron. Thanks to the integrated tube it delivers audiophile sound quality with an amazing warmth.

With integrated Nutube tube

The Nutube is a revolutionary, purely analog vacuum tube developed by KORG in cooperation with Noritake Itron Corporation. Like a conventional tube, the Nutube contains an anode, a grid and a heating wire. Therefore, it reacts exactly like a triode tube in a conventional amplifier, although it is much more compact and reliable and also consumes much less energy. The transparent housing of the HA-S headphone amplifier invites you to marvel: Here, the cards are played with an open mind, and the glow of the tube shows who is to thank for the warm sound.

Highest energy efficiency

The heating wire of the Nutube tube is fed by a DC/DC converter, which consumes less power than the tube circuits of an amplifier. The design is so efficient that the HA-S only needs 26V to power up the Nutube. With only two AA batteries, you get a full, authentic tube sound.

Sound possibilities

The HA-S offers a NFB switch (negative feedback) for switching between a filigree HiFi sound and a warmer, overtone-rich reproduction that only a tube can provide.

When the NFB switch is not active, the Nutube (a triode) overtones are highlighted - this automatically makes the sound warmer, fuller and more structured. When the NFB switch is activated, the distortion ratio and frequency response change, resulting in a smooth and detailed sound transmission.

For even more sound options, there are two operational amplifier options: The "MUSES01" for the most demanding applications and the industry standard "NJM4580", both from JRC. These OPs can also be interchanged as desired, allowing even the most sensitive listener to be perfectly matched by other operational amplifiers.

For advanced users, KORG offers the circuit diagrams of the amplifier free of charge on the Internet. In this way, certain components can be easily modified to adapt the sound and performance of this headphone amplifier to the particular requirements of the listener. There are innumerable possibilities!

- Vacuum tube: Nutube 6P1

- Connections: INPUT/OUTPUT Stereo mini jack

- Controls: volume, NFB switch (negative feedback) inside the housing

- Output impedance: 15Ω, recommended load 15Ω or more

- Power supply: 2x AA alkaline batteries

- Running time: ±9 hours

- Dimensions (W x D x H): 111 × 65 × 29 mm

- Weight: 110g, without batteries