A 60W output guitar-use head amp and cabinet set equipped with a Nutube 6P1 together with pre/power amps. The preamp features both clean and lead channels. In addition to Nutube, the power amp combines a ValveReactor circuit, which reproduces a tube/power amp operating environment, and a digital power amp (ICEpower), allowing users to experience fat sounds and details unique to vacuum tubes. Also, wattages can be changed without losing the tone of the power amp.
This amplifier was part of the Nutube announcement event at the KORG booth at Winter NAMM 2015 and was the first prototype to feature Nutube.

■Nutube demonstration at Winter NAMM 2015

An Overdrive stomp pedal equipped with a single Nutube. With a hybrid configuration of Nutube and discrete circuitry, it covers a range of sounds from clean to distorted. Just by using the guitar’s volume the user can harness the natural unique clipping characteristics of vacuum tubes.
Controls consist of GAIN, BASS, MID, MID-FREQ, TREBLE, and VOLUME. Mid frequencies can be varied, with a large degree of freedom in tone. It operates with a 12V AC adapter.
The right foot switch is typically called the “DOUBLE SW”, and plays a role similar to a boost switch. Nutube contains two independent vacuum tube circuits, with signals typically passing through just one circuit at a time. However, when the DOUBLE SW is pressed, both circuits are activated, making it possible to create a fatter, deeper tone.
This prototype was exhibited at the KORG booth at Winter NAMM 2015 along with the “Nutube Guitar Amp System”.

This new ValveReactor system takes advantage of Nutube’s merits, such as even greater miniaturization, power saving, and improvements in reliability.

A rack mount product based using Nutube in the preamp, operating at AC100V. The tonal range has been widened with the addition of a new clean channel. Equipped with 2 Nutubes, 1 per channel.
The Nurack-G also supports headphone output that can double for recordings as a direct out through a cabinet simulator that can be turned ON/OFF.

A hybrid configuration of Nutube + class D headphone amp. You can switch between Nutube and OP amp configurations at the pre stage. It employs a damping factor circuit which attains the same results as a vacuum tube + OUTPUT TRANS. It is contained in a robust aluminum case chassis.

This 100W+100W (4Ω) output stereo audio power amp operates at AC100V. 2 Nutubes are used on the left and right channels making use of Nutube’s linearity, producing no feedback and adding a moderate overtone to musical compositions.
The power amplifier utilizes the well-established ICEpower 125ASX class D amp unit.
With the vacuum tube amp, which makes use of an output transformer, peculiarities in frequency characteristics are produced through the interaction between the transformer and speakers, often said to be an important aspect of the tone of a vacuum tube amp. As output characteristics of vacuum tube amps which utilize output transformers are also reproduced, an even more vacuum tube amp-like tone is realized through adding speaker feedback. The Nutube Audio amp is also extremely light at approx. 2.3kg.

This kit allows users to easily enjoy the Nutube sound by connecting headphones or audio equipment. A limit run of 90 kits were sold at “Maker Faire” Tokyo 2016.

■Inputs/Outputs: Input (RCA) x2, Output (RCA) x2, Headphone out (stereo/mini jack)
■Preamp: Nutube 6P1 x1
■DC jack: External negative (KORG KA251 equivalent)
■Battery holder: 006P battery compatible, square battery holder
■Size: Letter size
■Power supply: 2 power supply system (6~12V)
■Battery life: Approx. 10 hours (when using alkaline square batteries)