Korg Nu:Tekt NTS-2

An oscilloscope can be very handy when working with synths and CV signals — but most aren’t designed with music‑makers in mind. The NTS-2 is.

Modular synthesizers are fashionable and pleasingly affordable, and many conventional synths now include control voltage (CV) and gate connections for interoperability with modular hardware, drum machines, and even effects devices. When connecting these things together, it’s often helpful if you can view the control voltage and gate signals to check whether they are actually doing what is expected, and it’s often handy to view oscillator waveforms too. The device needed to do this is called an oscilloscope.

Traditional analogue oscilloscopes with cathode ray display tubes tend to be large, heavy, expensive and quite technical to configure and use, and they aren’t equipped with audio‑friendly connectors. Modern digital ’scopes aren’t much better either. Added to which, an oscilloscope usually only does the one thing — it displays the waveform from one or two varying input signals.

Korg’s Nu:Tekt NTS‑2 oscilloscope kit is rather different, in that it’s very much intended for use by music makers — in fact, Korg describe it as “the musician’s Swiss Army knife”! This pocket‑sized device features a 2.8‑inch colour LCD screen and is less expensive than most proper ’scopes, yet provides four — yes four! — input channels, all of which have standard 3.5mm TRS jack sockets. More than that, though, the NTS‑2 also provides an FFT mode that allows you to analyse the harmonic spectrum of input signals, plus two independent and very comprehensive signal generators (which are permanently available), and a very useful pitch tuner mode.

Construction

The NTS‑2 comes as a self‑assembly kit with pre‑populated circuit boards — assembly took me only 15 minutes.

The NTS‑2 comes as a complete kit of parts with a simple four‑stage construction process that can be completed in about 15 minutes (an assembly tutorial video is available: https://youtu.be/Fx2wZ-Baz7g). There are two main circuit boards in protective bubble wrap, along with some aluminium corner pieces, a bag of screws, and a teeny‑tiny screwdriver. There’s also a 3.5mm TRS‑TRS audio cable, a USB A‑C cable for powering, and some stick‑on rubber feet.

Assembly starts with a slightly nervewracking process of snapping small rear and front panels away from the bottom battery panel and top display PCB — the whole lot is manufactured as one large fibreglass piece, which presumably keeps costs down. But although some care and patience is required, it’s not difficult. In the same way, a couple of small spacer pieces are snapped away from the lower input PCB, although these and two others are only required if you want to make and attach side brackets to support the display on a desktop (a template is included for making said DIY side panels).

The four aluminium corner extrusions are bolted onto a pair of aluminium side panels using tiny bolts, and then these completed side pieces are affixed with larger bolts to the bottom board carrying the battery holder. I found these small bolts a little fiddly to work with, and preferred using a jeweller’s screwdriver over the miniature one included in the kit, but with patience and a steady hand I completed the task without any cursing.

Next, the input connector board is plugged into the back of the top display board, and then the cable from the battery holder is plugged into a socket at the side of the input board. Finally, the whole top assembly can be screwed down onto the corner pieces and the front and back panels fitted with more tiny screws — the back panel carrying printed labels for all the connectors and on/off button. And that’s it: assembly is complete, and the unit ready to use.

Ready, Set, Go

The completed Oscilloscope measures 129x78x39mm and weighs about 130g, so it’s genuinely pocket‑sized! Two AAA alkaline batteries will run the ’scope for a few hours, but I think most will use the included USB cable to derive power from either a standard charger wall‑wart (providing 5V DC and at least 550mA) or a computer. Separate Auto‑Off durations are available for battery and USB powered operation (the default is one hour for both, but there’s a permanently on option, too).

There are four inputs and outputs, with two channels on each of two minijack sockets, and there’s a handy pair of thru sockets too.

The four input channels are accessed via a pair of 3.5mm TRS (stereo) sockets on the rear, so breakout Y‑cables might be required in some applications (I used 3.5mm TRS to dual 6.35mm TS cables, as most of my gear uses quarter‑inch CV/gate connections). If mono TS plugs are used only two channels can be accessed, of course. Usefully, both input sockets have associated (stereo) thru output sockets, so the NTS‑2 can be patched permanently across up to four signal paths, if required. A third pair of 3.5mm sockets, monaural TS types, provides the outputs from the two internal signal generators. The last connector is a USB‑C port for powering, while a power button turns the unit on/off.

Moving on to the top control panel, five buttons are arranged across the bottom of the LCD screen, the first choosing the working mode. The functions of the other four vary depending on the current display mode. A sixth button starts and stops oscilloscope measurements, but also turns the signal generator outputs on/off when configuring them (a pair of LEDs light when the generator outputs are active). A knobless rotary encoder has a detented action and alters the value of the currently selected on‑screen parameter.

The operating paradigm is obviously menu‑driven and mostly self‑explanatory, although I did have a few head‑scratching moments (such as wondering why I couldn’t get outputs from the generators!). The kit didn’t include a printed user manual, but thankfully I was able to download one from the web (click here). It’s only four pages long but I’d definitely recommend reading it to learn about all the features and operations the NTS‑2 is capable of — this is a surprisingly powerful and capable product that really does justify the Swiss Army knife description!

Operations

Pressing the Mode button cycles around the four core functions of Oscilloscope, Signal Generator, Spectrum Analyzer and Tuner, with a fifth option for Global settings. In ‘Scope mode, the assignable buttons access the display mode (overlaid, two‑ or four‑channel displays, and X/Y Lissajous), vertical and horizontal resolutions (10mV to 10V, and 50µs to 1 second per division), and the triggering mode and sensitivity.

The Wave mode accesses the two independent signal generators, each working as an audio oscillator (sine, square, triangle, or saw wave shapes), an LFO, a noise generator (pink or white), and a pulse/envelope generator. Options are included to adjust the pulse/envelope bpm (0.5‑600), as well as polarity, duty cycle and phase of the oscillator/LFO signals (both spanning 0.01Hz to 10kHz).

When the FFT (spectrum analyser) mode is selected, the configuration options include selecting the input source(s), the vertical display resolution, the horizontal frequency range (0‑20 kHz), and the trigger level and type. In Tuner mode the reference pitch is adjustable between 410 and 480 Hz, any of the input sources can be selected individually or in pairs, the display type can be chosen (needle or linear meter), and the oscilloscope traces can even be displayed underneath, if required. The detected pitch is given in equal temperament notes between E0 and G8, accurate to ±0.1 cents.

Global settings include things like AC or DC coupling, low‑pass filtering (to remove HF noise and clean up the traces), and the trigger source for the ’scope inputs. Display brightness, auto‑off durations, and a couple of other display options are also provided. For technical completeness, the input impedance is a whopping 1MΩ on all channels, with ±10V (+19dBu) maximum input level, while the generator outputs are limited to a ±5V range (+13dBu) with a low 47Ω output impedance.

Impressions

Korg’s Nu:Tekt NTS‑2 kit is impressive, and very satisfying to both assemble and use. I have already found it invaluable for checking control voltages, gates and audio waveforms in my modest synth rig, which comprises a Moog Subsequent 37CV, an ARP Odyssey, a Korg MS20FS, a CP251 controller, and various MoogerFooger effects units.

This is a surprisingly powerful and capable product that really does justify the Swiss army knife description!

Undoubtedly, there are cheaper and simpler digital LCD oscilloscopes on the market, as well as many pre‑loved vintage CRT units, but the NTS‑2 has the real‑world advantage of being fully optimised for exploring audio and CV signals, with sensible control ranges and familiar connectors. The inclusion of an X/Y function in the ’scope makes for mesmerising displays, while the FFT mode is really welcome for analysing the harmonic content of audio signals. Likewise, the tuner function gives reassurance and helps align synth oscillators to a known reference. The two independent signal generators are also extremely useful not only for system testing, but also as additional audio, LFO or trigger sources within any synth setup.

I can see this oscilloscope kit being a very useful tool in any modular or semi‑modular rig, and it lends itself to being built into a custom rack panel, console frame, or used as it comes, as a free‑standing desktop unit. Either way, it always looks very cool while providing really useful information. I’m very glad I bought one — I use it almost every day!