Nutube is a new and revolutionary fully analog vacuum tube developed by KORG INC. and Noritake Itron Corporation. The same as a conventional vacuum tube, Nutube is constructed with an anode, grid and filament, and operates as a complete triode tube, effectively generating the response and same rich harmonic characteristics of conventional vacuum tubes in a more compact, stable and energy-efficient way.

The transparent case of the HA-S delivers a glimpse into this technology; allowing the glow of the tube to be visible at all times. 

Energy efficiency

The filament of the Nutube is powered by a DC to DC converter, which consumes less electric current and thus allows for a longer battery life than other vacuum tube equipped amplifiers. The design is so efficient that the HA-S can drive the Nutube with a line voltage of 26 V using only two A4 batteries., for a rich and authentic vacuum tube sound.

For further sound modification, we have included two OP amp options for the output: the premium audio oriented "MUSES01" and the industry standard “NJM4580”, both from JRC. These can be easily replaced so even the most purist audiophiles will be able to customize and adapt the sound of their HA-S to heir heart’s content.

For advanced users who want to customize their amplifier even more, the circuit diagrams are readily available, making it really easy to change discrete components and make your own and unique headphone amp matching your desired tone and performance -, the possibilities are endless!