RNDI-M
Active Transformer Direct Interface
OVERVIEW / MEDIA / FEATURES / REVIEWS / SPECS & RESOURCES
Compact design – giant tone.
The RNDI-M brings the stunning tone & clarity of its award-winning counterparts to an even more compact and pedalboard-friendly format, with the exact same custom Rupert Neve Designs transformers and discrete FET input stage as the best-selling RNDI, RNDI-S and RNDI-8.
By streamlining its feature set and housing the electronics in a rugged & more compact chassis, the RNDI-M fits neatly into any space and will allow even more musicians and engineers to tap into the uncompromised sonic power & vibrancy of a Rupert Neve Designs DI.
“I didn’t know what I was missing until I plugged into the RNDI. ”
The RNDI-M provides instrument direct injection for electric guitar & basses, synthesizers, keyboards, piezo pickups, or any other instrument-level source.
The discrete, Class-A circuit topology is built around Mr. Rupert Neve’s custom transformers, resulting in outstanding sonic performance and strikingly natural sound from below 5Hz all the way up to well beyond 90kHz. It can handle input levels up to +20.5dBu, the low impedance, transformer-coupled output stage drives long lines with minimal loss, and the rugged steel chassis is designed for a lifetime of stage and studio use.
The RNDI-M’s Origins
After coming into existence during an experimentation with new transformer designs, the RNDI circuitry was fine-tuned over a series of listening tests against the most popular high-end DIs available. It was in these tests where the RNDI always seemed to add another dimension to the sound and bring the instruments to life. The lows felt richer, deeper and fuller, and the highs had outstanding clarity without any added harshness.
Most importantly, the design team noted: “As musicians, the RNDI consistently stood out as the DI we wanted to play through.”
Over 35,000 channels of RNDI have been sold since its debut in 2015, and they are in daily use in studios and on stages with the world’s biggest artists: Billie Eilish, The Rolling Stones, Olivia Rodrigo, Paul Simon, Billy Strings, AC/DC, Thundercat, Tycho, Halsey, Jack White, Stevie Wonder, and countless others.
Signature Sound
The RNDI-M’s signature sound is primarily the product of a custom Rupert Neve Designs transformer and a class-A, discrete FET input stage. The carefully orchestrated union of these two elements is key to the RNDI-M’s unique accuracy, tone, and response.
THE CUSTOM TRANSFORMER
The RNDI-M’s custom-wound output transformer provides exceptional passive isolation while adding musical harmonics and dimension to the sound. The low impedance, transformer-balanced output excels at driving long cable runs, and its performance is consistent regardless of the connected equipment. This is equally important for both live and studio environments where the audio signal may travel almost 100ft before hitting an amplifier.
THE CLASS-A, DISCRETE FET AMPLIFIER
The class-A, discrete FET input stage in the RNDI-M is powered by external +48V phantom with a high impedance input of 2.2 Megaohms that ensures consistent performance with a wide variety of instruments & other sources. The class-A design ensures that zero crossover distortion is added to the signal, which can add upper-order odd harmonics that are musically dissonant in nature. With the RNDI- M, the majority of harmonic content is a pleasing combination of 2nd order (octave) and 3rd order (fifth above octave). These musically relevant harmonics, present in subtle amounts, enhance the richness of the original signal and provide a distinctly musical response. Furthermore, the discrete aspect of the RNDI-M’s design means there are no ICs or digital components that may cause negative effects on the tone.
Wide Bandwidth, Giant Headroom
The RNDI-M is flat within a quarter dB from 28Hz to 60kHz, +/- 1dB up to 90kHz, with low frequency response all the way down below 5Hz. However, measurements are only part of the equation: combine this extended bandwidth with the output transformer’s harmonic enhancement, and a thunderous low-end emerges that feels an octave deeper than anything else without losing any midrange richness or top-end sparkle.
For Guitar, Bass, Synth, Keys, and more
The RNDI-M’s uniquely high input headroom of +20.5 dBu is capable of handling not only instruments, but a wide variety of sources such as synths, keyboards, drum machines and even pre-recorded material. This allows the RNDI-M to inject that coveted Rupert Neve Designs tone into a huge range of sources.
FEATURES
Groundbreaking Direct Tone
When class-A, discrete amplifiers meet Rupert’s custom transformers, amazing things happen. The RNDI-M contains the unique components and design knowledge that makes it worthy of the Rupert Neve name.
Huge Headroom
Maximum input level is a massive +20.5dBu, making the RNDI-M capable of handling not only instruments but also keyboards, drum machines and even pre-recorded material.
Rugged Solid Steel Frame
The rugged steel chassis is built to withstand the severe stresses of life on the road.
Use a Variety of Sources
The RNDI-M has immensely consistent performance across a wide variety of sources due to its 2.2M Ohm discrete FET input stage and high headroom. The RNDI-M can be used with confidence on guitars, synths, basses, acoustic instruments, keyboards & drum machines.
Drive Longer Lines
The low impedance transformer coupled output – below 40 ohms – is capable of driving long lines while maintaining exceptional high frequency performance.
1/4″ THRU Output
The THRU output can be used to maintain optimal input level to an amplifier with no signal degradation.
Ground Lift
A Ground Lift switch is provided on the rear panel to isolate Pin 1 on the XLR balanced output from the circuit ground to help fix any potential grounding issues.
Phantom Powered
The RNDI-M is powered by standard 48V phantom power. Power is indicated by a blue LED on the front panel.
RNDI REVIEWS
“The RNDI provides the most accurate representation of my instrument and individual playing, in detail and sonic character, in that sense of ‘I didn’t know what I was missing’ until I plugged into the RNDI.”
Tom Blankenship, Bass
My Morning Jacket
“It’s an incredible unit. Pretty much everything I do is DI – synths, guitar, bass – and this is the best starting point for that because you have the most honest representation of the original performance and the instrument possible…there’s this weight to the low end and a sheen to the top end that’s very pleasing. It doesn’t get brittle, and the low end stays tight…it’s a fantastic DI.”
Tycho, Musician
“It goes like at least a half an octave, if not an octave lower than everything else. All that stuff that you always fight for? It’s just there.”
F Reid Shippen
Ingrid Michaelson, Kenny Chesney, Dierks Bentley
“For production rehearsals, day one they gave me an RNDI. I plugged it in…and I had never heard my bass sound as good. Ever. The low end, the crispness, just the tightness of it all, it was so amazing. I literally left rehearsal and bought one for myself. I don’t ever want to be without this, ever.”
Matt Reilly, Bass
Avril Lavigne
“This guy has been it for me since I first heard it…the best DI freakin’ out there, man. And I’ve tried them all.”
Roger Lima, Bass
Less Than Jake
“…my secret weapon…it’s just something where I have no words for it. The magic of the color…it goes down to 12Hz, or 10Hz…you can’t believe the sonic colors you get out of it.”
Snow Owl
The World of Hans Zimmer
“I’ve been using the RNDI for years – the best thing that was ever created. I play the bass guitar, and this is what I use all the time, for everything I do. For the Wailers band, we have about eight of them, and we use them for they keyboards and the triggers. I’m a huge fan of Rupert Neve.”
Aston Barrett Jr, Bass
The Wailers
“The RNDI is our ‘speaker level DI box’ of choice. To put it simply, it sounds better than anything else. We need the best quality at every step of the signal chain. Why put $4,000 worth of mic and preamp in front of a $10,000 guitar amp and then use a rinky DI? We needed the real thing, and Rupert Neve is the name that guarantees quality.”
Matt Picone / Fractal Audio
“I'm still in disbelief as to how much of a difference there can be between two high quality direct boxes. This one is miles above everything else I have ever used. The difference is NOT subtle. Absolutely love it!”
Fred St-Gelais, Producer
Celine Dion, Marc Dupré, The Masked Singer
“The RNDI is an exceptional DI box, and the addition of a speaker mode makes it a very useful tool, both in the studio and on stage.”
Mike Hillier / MusicTech
“The RNDI is certainly a class act…a superb DI box that can add its character to the colors of your sonic palette. The RNDI isn’t cheap, but quality never is. Highly recommended.”
Bob Thomas / Sound on Sound
SPECIFICATIONS & DOWNLOADS
Note: All specifications are typical.
NOISE (22 Hz - 22 kHz, Un-weighted)
Better than -110 dBV
INPUT IMPEDANCE
Instrument Input: 2.2 Megohm
OUTPUT IMPEDANCE
Less than 40 Ohms
MAXIMUM INPUT LEVEL
Instrument Input: +20.5 (8.2 Volts RMS)
MAXIMUM OUTPUT LEVEL
+11.5 dBu Typical
FREQUENCY RESPONSE
+/- 0.25 dB from 28 Hz – 60 kHz
+/- 1 dB from 14 Hz – 90 kHz
-3 dBu below 5 Hz
TOTAL HARMONIC DISTORTION + NOISE
@ 1 kHz, +20 dBu input level: 0.25% Typical (2nd and 3rd Harmonic)
@ 1 kHz, -20 dBu input level: 0.015% Typical (2nd and 3rd Harmonic)
@ 20 Hz, -20 dBu input level: 0.75% Typical (2nd and 3rd Harmonic)
POWER REQUIREMENTS
4.5mA @ +48VDC
WEIGHTS & DIMENSIONS
Product Dimensions (W x D x H): 3.25” (8.25 cm) x 4.75” (12.1 cm) x 1.75” (4.45 cm)
Shipping Dimensions (L x W x H): 4.125” (10.5 cm) x 5.125” (13 cm) x 2” (5.1 cm)
Shipping Weight: 1.25 lbs. (0.57 kg)
FREQUENTLY ASKED QUESTIONS
The RNDI-M uses the exact same custom transformer and discrete FET input stage as the best-selling RNDI, RNDI-S, and RNDI-8. It’s also still made in America – just like all our gear. The only difference from the RNDI is the omission of the Instrument / Speaker level switch, and the fact that it’s about 30% smaller.
While we don’t recommend it, the RNDI-M has +20.5 dB of input headroom so it’s usually OK. We do stress being careful with your gain staging when doing this to avoid any potential clipping…
No. It is true that the higher input impedance of an active DI will generally result in greatly enhanced frequency response on a passive bass, but there are still advantages to an active DI on active basses as well. We recommend trying things out and letting your ears decide what tool works best.
The following may also be of interest:
RNDI Active Transformer Direct Interface
RNDI-S Stereo Active Transformer Direct Interface
RNDI-8 8 Channel 1U Direct Interface
The Shelford Channel