Bat Utility Belt: Korg Nu:Tekt NTS-1 Review

We review Korg’s new NTS-1, a compact synth and effects processor you can assemble and customize to make your own.

When Korg released its bestselling Prologue synth in 2018, it included a sleeper feature: third-party programmers could create custom oscillators and effects. The Minilogue XD soon joined the party, lowering the admission price from $1,000 to around $550, and developers responded. Last I checked, more than 80 downloadable oscillators and effects were on the Logue developer site, many of them free.

Then Korg did something to make those sounds even more accessible: they released the NTS-1, a $99, pocket-size monosynth with a Logue-compatible oscillator and effects. The NTS-1 came out last September, but it’s just now trickling into stores. I was fortunate to pick up a kit at NAMM, and I spent the last month building it, modding it, and playing it. (The building was the fastest part, as you’ll see.) You do give up some conventional features for the low price, but the NTS-1 has a fresh sound and a surprising amount of potential that will continue to grow as more add-ons appear.

Overview

Like all Nu:Tekt gear (Korg also offers the HA-S headphone amp and OD-S overdrive pedal), the NTS-1 comes as a box of parts you screw together. The finished NTS-1 is a tad over 3×5 inches (129 x 78mm) and 4 ounces (124g). It has just one oscillator, but that includes a waveshaping function that adds richness and animation. It also has a multimode resonant filter, an amplitude envelope, and LFOs for the oscillator (pitch or waveshape) and DCA (tremolo). You get three serial effects—modulation, delay, and reverb—and you can mix an external stereo signal into any point in (or after) the effects chain. In addition, it has an arpeggiator, a tiny speaker, and a 5/8-inch-tall ribbon keyboard. 

I discovered that only the middle third of the keyboard (a 1/4-inch band) responds to touch. Having the keyboard and speaker was convenient, though. Other physical controls include a rotary encoder for selecting parameters, two pots for adjusting values, and seven buttons. Long-pressing the buttons while turning the knobs accesses more parameters, so you have more control than you’d first think. You can also control almost everything through MIDI. (See the table, “Korg Nu:Tekt NTS-1 MIDI Control,” below.)

Building It

No soldering is necessary to build the NTS-1. The main components are two circuit boards, four metal corners, two metal side panels, the adhesive ribbon keyboard, and a mass of tiny screws. Korg thoughtfully includes a tiny screwdriver, but do yourself a favor and grab a full-size one. Moving carefully, I assembled the whole instrument in less than 25 minutes. (I also built the HA-S headphone amp, which has fiendishly tiny screws that took almost an hour to wriggle into place.)

I highly recommend watching the assembly video; it’s an essential complement to the messy printed manual. The only strange part of the build is breaking one of the circuit boards into four pieces to make the top, bottom, front, and back of the case. The pieces snap apart with some gentle bending, but the resulting edges are rough, so you may want to file them. 

In short, assembling the NTS-1 is about as easy (and rewarding) as building an IKEA bookcase; the real DIY action comes from modifying it. Using the diagram in the manual and a utility knife, I carved custom side panels out of 1/8-inch Masonite (see photo). The final instrument feels remarkably sturdy, though I’m considering mounting mine in a larger case with cable extensions to reduce wear on the jacks.

At NAMM, Korg previewed the Custom Panel, an alternative faceplate with connections for Arduinos and other electronic components. The NTS-1 Customizations site has instructions for building and programming your own hardware interfaces. And of course, savvy programmers can create new oscillators and effects.

Oscillator and EG

The NTS-1’s main personality comes from its digital oscillator. Four waveform types are built in: saw, square, triangle, and VPM (an FM variant). You select them by twisting the TYPE encoder. Knob A changes the waveform shape, and Knob B changes an Alt parameter—suboscillator level for the first three and FM ratio for VPM.

With user oscillators, the knobs can change other parameters the programmer specified. For example, on Roll-log Sounds’ Scan oscillator, Knob A scrolls through a wavetable. And on the Pluck oscillator from Len, Knob B changes the character of the attack from a crisp pick to a soft fingertip. On most user oscillators I tried, you can access even more parameters for Knob B by holding down the OSC button and turning the TYPE encoder.

Holding down the OSC button also lets you access a dual LFO. In this mode, Knob A sets the LFO rate, and Knob B sends its output to the main oscillator’s pitch or waveshape, depending on whether you turn the knob left or right. (Turning it to 12 o’clock sets the depth to zero.) The range is extreme, which is great for sound effects, but tough to control for vibrato. My favorite approach was to add subtle timbral animation by setting Knob A to a slow sweep and Knob B to a gentle shape-shift.

To simulate mod-wheel vibrato, I used the hidden tremolo feature instead. When you hold down the EG (amplitude envelope generator) button, knobs A and B control tremolo rate and depth. I set the rate to 5 and assigned the mod wheel on my MIDI keyboard to transmit CC21. (This is labeled Rate in the MIDI implementation chart but actually controls depth.) The EG offers four shapes: ADSR, AHR (higher sustain level), AR (no sustain), and AR Loop, which creates pulsing sounds. In all cases, the two knobs control attack and release.

How’s it sound? The built-in oscillators are clear, gaining richness as you add waveshape modulation. I could hear aliasing in extreme high notes, but it has an appealing ring-modulated character.

Adding new oscillators and effects is easy. You download files, drag them to the Mac/Win librarian (see screenshot), and transfer them to the NTS-1 over USB. The NTS-1 stores 16 custom oscillators and 24 custom effects (in 3 groups of 8). One caution is that the NTS-1 has less processing power than the pricier Logues, so some custom oscillators crackle if you enable all three effects.

Of the third-party oscillators I tried, I particularly liked Len Pluck, Hammond Eggs Souper (a supersaw), and Ghost Time Games’ spooky Warped. I also had a blast with Roll-log’s wavDesk and wavShelf, two computer utilities that convert WAV files into looped samples or scannable wavetable oscillators.

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Filter and Effects

The filter section offers lowpass, bandpass, and highpass shapes, all with resonance and 2- or 4-pole slopes. Instead of a filter envelope, you get a ramp that can fade the filter attack up or down. (Hold the FILTER button to adjust the rate and amount.) The filter didn’t burble with personality, but third-party filters are available as modulation effects.

Effects are a high point of the NTS-1. The MOD button calls up chorus, a rich ensemble, phaser, and flanger, all with time and depth controls. Delays include mono, stereo, ping-pong, highpass, and a lovely tape emulation. Changing the time produces trippy, analog-style glitching. Cranking the Depth control (feedback) creates infinite repeats for instant soundscapes. 

The maximum delay time is about 650ms; third-party delays include extended loopers. Unfortunately, there’s no tempo sync. At 120 bpm, I got rhythmic echoes by sending CC30 with values of 5, 13, 33, 52, 62, 92, and 122. Reverbs include hall, plate, the appropriately lush Space, and two pitch-shifted effects: the shimmery Riser and gorgeous Submarine.

If you plan to use the NTS-1 as a set-and-forget effects processor, note that it goes to sleep after 15 minutes. That was never an issue for me, because waking it up requires a simple tap on the OSC button.

Update: Firmware update 1.20 lets you disable sleep mode. See the details in my Instagram post.

Arpeggiator, Sync, and MIDI

I found the arpeggiator handy for live jams. The first six buttons set various chords. Holding the ARP button lets you latch playback and adjust the tempo and number of steps. Although the tempo syncs to MIDI and analog sync signals, I wish the NTS-1 would arpeggiate incoming MIDI notes instead of just changing the root of the chord. I was able to add swing by connecting Korg’s SyncKontrol app (see photo).

In the MIDI department, the NTS-1 responds to velocity (amp level), pitch bend, and so many CCs that you could turn a sequencer into a patch librarian (see table). Surprisingly, it ignores the common CC1, CC7, and CC64 (modulation, volume, sustain), so I remapped my keyboard’s mod wheel to control either tremolo (CC21) or waveshape (CC54).

Conclusions

The NTS-1 is essentially a development board for oscillators and effects, but it has enough synthesis features to make it an appealing add-on instrument, and more than enough to be a terrific effects processor. The compact size, MIDI control, ability to run from USB power packs, and stereo input make it easy to integrate into any setup. And the quality and variety of sounds make it a bargain for $99. (Plus, Korg includes a big bundle of soft synths and music software.)

My wish list is small: tempo sync for the delay, a dedicated vibrato LFO, portamento, a full filter envelope, and a few more knobs. When the NTS-1 does hit stores in bulk, Korg will have a hard time keeping it in stock.

Website: Korg.com

Price: $99

Korg Nu:Tekt NTS-1 MIDI Control

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