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.
“As with the original RNDI, the subtle but distinctive sense of warmth, definition and depth is extremely attractive...”
— BOB THOMAS // SOUND ON SOUND (MAY 2025)