Rupert Neve Designs RNDI-8 Eight Channel Active Transformer Direct Interface

8 Channel 1U Direct Interface



12-Month Special Financing**


Legendary tone, unquestionable reliability. Eight channels of the superb-sounding RNDI in one rack space.

With over 25,000 channels shipped since its launch in 2015, the RNDI is firmly established as the direct interface of choice for many of the world’s most discerning musicians and engineers. Its custom transformers and discrete FET amplifiers deliver a vibrancy and clarity that captures the full harmonic depth of any source, and its unquestionable reliability has led to its adoption by thousands of touring artists. The RNDI-8 puts eight channels of this beloved circuit into a single rack space, making it the ideal solution for high-end stage rigs, studios, and synth enthusiasts. With the RNDI-8, stunning direct sound doesn’t require extra work – it’s just there.

The RNDI-8 consists of eight independent channels of RNDI Active Transformer Direct Interface in a single rack space, providing instrument direct injection for electric guitar & bass, synthesizer, keyboard, piezo pickup, 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 supremely natural sound from 5Hz all the way out to well beyond 90kHz. Each channel can handle input levels up to +21dBu (+31dBu with the pad engaged), the low impedance transformer-coupled output drives long lines with minimal loss, and the rugged chassis’ steel construction is designed for a lifetime of stage and studio use.

Transformer + Discrete FET: The Best of Both Worlds

The RNDI-8’s signature sound stems from the custom-designed transformers and class-A, discrete FET input amplifiers. The carefully designed union of these two elements is key to the RNDI-8’s unique accuracy, tone, and response.

The Eight Custom Transformers

The RNDI-8’s custom-wound output transformers provide isolation while adding musical harmonics and dimension to the sound. The low-impedance, transformer-balanced outputs excel at driving long cable runs, and the performance is consistent regardless of the connected equipment. This is important for both live and studio environments where the unamplified signal may travel 100ft or more before hitting an amplifier.

The Class-A, Discrete FET Input Amplifiers

The class-A & discrete FET input amplifiers in the RNDI-8 are powered by 48V phantom and create a high impedance input of over 2M Ohms, ensuring consistent performance with a wide variety of instruments. The class-A design eliminates crossover distortion that can otherwise be added to the signal and introduce unwanted upper-order odd harmonics. With the RNDI-8, the harmonic content is derived from the octave (2nd order) and fifth above octave (3rd order) relative to the fundamental. 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-8’s design means there are no ICs or digital components to potentially cause negative effects on the tone.

Giant Headroom, Wide Bandwidth

The RNDI-8 has a uniquely wide bandwidth with a frequency response stretching from 5Hz all the way past 90kHz. However, measurements are only part of the equation: couple this extended bandwidth with the output transformer’s harmonic enhancement and an absolutely thunderous low-end emerges, adding an unparalleled feeling of depth. All this happens without compromising any of the midrange richness or top-end sparkle that defines your instrument.

Maximum input level is a massive +21dBu, making the RNDI-8 capable of handling not only instruments but also professional line-level sources like interfaces and drum machines. And with the addition of a – 10dB pad, that number soars to +31dBu – more than enough for even the highest-output DJ mixers. This makes the RNDI-8 incredibly versatile, enhancing the sound of nearly any connected instrument or source.

Two Distinct Ground Lift Options

Most direct interfaces include a ground lift switch at the output, and the RNDI-8 includes this standard DI ‘lifting’ option via eight individual ‘Pin 1 Isolate’ switches on the rear panel. Engaging this button will usually eliminate common sources of hum in the signal path. However, the RNDI-8 also includes eight ground lift buttons on the front panel which separate each channel’s circuit ground from the chassis ground, providing another helpful option to detect and eliminate unwanted ground hum.


  • IN
    • Hi-Z unbalanced input. ZIN = 2.2MΩ
  • THRU
    • Parallel ¼” jack that allows the user to pass the input signal directly to an amplifier.
  • 48V
    • Indicates when +48VDC phantom power is active on the channel.
    • Isolates each channel ground from the chassis ground.
  • -10dB PAD
    • Attenuates the input signal by -10dB (¼” THRU unaffected).


    • XLR DI output utilizing custom Rupert Neve Designs transformer. ZOUT < 40Ω
    • Isolates XLR Pin 1 output from circuit ground.



Groundbreaking Direct Tone

When class-A, discrete amplifiers meet Rupert’s custom transformers, magic happens. The RNDI-8 contains the unique components and design knowledge that makes it worthy of the Rupert Neve name.

Huge Headroom

Maximum input level is a massive +21dBu, making the RNDI-8 capable of handling not only instruments but also professional line-level sources like interfaces and drum machines. With the addition of a -10dB pad, that number soars to +31dBu – more than enough for even the highest-output DJ mixers.

Rugged Solid Steel Frame

The rugged steel 1U chassis features an industrial-grade powder coating and is built to withstand the severe stresses of life on the road. The included bolt-on rack ears are reversible for multiple mounting options.

Takes All Kinds

The RNDI-8 performs with immense consistency across a wide variety of sources due to its 2M Ohm discrete FET input and huge headroom, providing superb sound for guitars, synths, basses, acoustic instruments, keyboards, and even professional line-level devices.

Drive Longer Lines

The low-impedance transformer coupled output is capable of driving long lines with unrivaled high-frequency performance.

1/4″ THRU Outputs

The THRU outputs can be used to feed amplifier inputs for reinforcement.

Ground Lift Options

Pin 1 Isolate switches are provided on the rear panel to help fix any problematic grounding, as well as Ground Lift switches on the front panel to isolate each channel’s circuit ground from chassis ground.

Phantom Powered

Each of the RNDI-8’s eight channels is powered by standard 48V phantom power. Power is indicated by blue LEDs on the front panel, one per channel.


Note: All specifications are typical.

  • Input Impedance (ZIN)
    • Instrument Input: 2.2 MΩ
    • -10dB PAD Engaged: 200 kΩ
  • Output Impedance (ZOUT)
    • Less than 40 Ohms
  • Maximum Input Level @ 1kHz
    • Instrument Input: +21 dBu
    • -10dB PAD Engaged: +31 dBu
  • Maximum Output Level @ 1kHz
    • +11 dBu
  • Frequency Response (30 ft. output cable, 10k equivalent load)
    • +/- 0.25 dB: 28 Hz – 50 kHz
    • +/- 1 dB: 14 Hz – 90 kHz
    • -3 dB: 5 Hz
  • Noise (Measured Output, Un-weighted BW 22Hz – 22kHz, Source Impedance 150 ohms)
    • Better than -110 dBV
  • Total Harmonic Distortion + Noise (THD+N%)
    • @ 1 kHz, +20 dBu Input Level: 0.35% Typical (2nd and 3rd Harmonic)
    • @ 1 kHz, -20 dBu Input Level: 0.009% Typical (2nd and 3rd Harmonic)
    • @ 20 Hz, -20 dBu Input Level: 0.9% Typical (2nd and 3rd Harmonic)
  • Power Requirements
    • Phantom Powered, 4.5mA Per Channel @ +48VDC
  • 19” Rack Mounting Option
    • 1RU reversible bolt-on rack ears


Product Dimensions (W x D x H): 19” (48.3 cm) x 8.125” (20.63 cm) x 1.75” (4.5 cm)

Shipping Dimensions (L x W x H): 24” (61 cm) x 13” (33 cm) x 4” (10.2 cm)

Shipping Weight: 9 lbs. (4.1 kg)

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