A revolutionary collaboration between Japanese musical instrument manufacturer KORG INC and display manufacturer Noritake Co. brings us the Nutube, which exhibits the cathode-grid-anode structure of the traditional triode valve, but by applying technology from Noritake Co.’s vacuum fluorescent displays, allows for a device that has less than 2% of the power consumption of a traditional vacuum tube at less than 30% of the size.
Unlike legacy devices, the Nutube has a much lower thermal output and 30,000 hours of continuous operating life, allowing the device to be attached directly onto a high-density circuit board with the confidence that the component will not need to be replaced. Additionally, the Nutube’s cathodes do not require a separate heating element, illustrating the much cooler operating temperature of this new technology.
At present, the end use of Nutubes is primarily in the preamp stage of guitar and bass amplifiers to get the coveted sound characteristic of valve amplifiers but in a smaller, lighter package. Nutubes have also been used to make low frequency and audio frequency oscillator circuits, the latter as a unique sound source in a synthesiser.
Geared towards audio processing applications, the latest Nutube evaluation board (NEB-2) sports 4 selectable levels of harmonic distortion with independent switching for left and right channels, a signal bypass switch, stereo output volume control, and individual bias adjust controls for the left and right channels. The audio I/O connections are RCA pairs, and the board can be powered using between 7 V and 20 V; a 12 V DC jack comes as standard. The maximum input level is +2 dBu with a max gain of +10 dB, and the SN ratio is 100 dB. Supporting its status as a boutique audio component, the frequency response of the evaluation circuit is 20 Hz to 40 kHz, allowing for overtones far above the typical human hearing range.
Even though it is not a semiconductor device, I love this technology, and I am sure there is an audio electronics engineer among us who might like to dare to create some boutique end products for audiophiles. I am VERY happy to chat to anyone who is interested in getting a sample board.
(All images sourced from KORG)