Master Buss Converter

Dual Path AD Converter & Limiter


    The ultimate tool for creating digital signals with the tone, transparency, and power expected from Rupert Neve Designs.

    Whether you’re tracking, printing mixes or mastering, the Master Buss Converter is a revelation in quality and functionality of A-D conversion technology. The analog drive circuitry allows the MBC’s converter to be fed by either a class-A transformerless path for maximum transparency, or by custom interstage audio transformers with variable Silk for a wide variety of tonal enhancements. Coupled with an astonishingly musical limiter, the MBC is always the best choice to capture your analog signals with breathtakingly three-dimensional accuracy.

    A Long Time Coming

    With over seven decades of analog circuit design experience, Mr. Rupert Neve had never considered a converter worthy of his hallmark until the release of the RMP-D8 Dante-connected microphone preamplifier in 2018.  While the RMP was primarily designed as a mic preamp, its adoption by engineers at the highest levels of recording, mastering, and touring as their preferred converter led to the development of the MBC, creating a new standard for PCM conversion quality.

    Dual Path Analog Design

    As the last link in the analog chain before digitization, converter drive circuitry is critical in determining the imprinted digital sound quality. From the ground up, the MBC was designed for reference performance regardless of genre or desired sonic character, and the key to this lies in the quality and adaptability of the analog drive circuitry.

    “The new RND converter is the one you want. It’s worth twice what they are charging for it. It has replaced several high end converters in my rig.”

    Chris Athens, Mastering Engineer
    (Drake, Beastie Boys, DJ Khaled)

    For a bolder, more powerful imprint, a custom-designed inter-stage transformer with Rupert’s acclaimed Silk circuitry can be inserted to recreate the classic tonality of his vintage designs. Uniquely, unlike our audio transformers intended for line-level output, this new transformer is designed to achieve output transformer harmonic content characteristics at a level appropriate for input to the converter itself.

    With the addition of variable Silk, the engineer is able to precisely dial in the desired amount of harmonic content – with the Red mode highlighting harmonics in the mid and high frequencies, and the Blue mode accentuating harmonics in the low-end. From a subtle transformer tonality without Silk, to significantly more color than vintage modules with the Silk / Texture circuit fully pushed, the selectable transformer path fills your tracks with enhanced dimensionality and power.

    When maximum transparency and fidelity is desired, the transformerless path provides extraordinary detail and clarity. While many transformerless circuits suffer from thin tonal balance and a lack of punch, the MBC’s Class-A circuitry was painstakingly designed to deliver a beautiful sense of clarity, with vibrant detail at both high and low frequencies. As an additional tonal palette to capture your tracks, the transformerless path is an essential complement to the weighty, classic sound of the transformer path. No matter what sonic character you’re seeking, the MBC can provide it at the push of a button.

    “What I really like about the MBC is at the conversion stage I’ve got access to the limiter, the transformer with silk to really dial in my sound.  It gives me the color I need, the sound I need, it’s easy to use and everything sounds good through it.”

    Patrick ConwayDave Matthews, Nick Lowe, Molly Tuttle

    Compound Active Release Analog Limiter

    The challenge here was to design a limiter that could act as both a musical sculpting tool exceeding the quality of available plug-in limiters, while also being able to act as a transparent safety limiter for tracking or live performance & broadcast.

    To further adapt the sound of the limiter, we’ve added a number of controls to fine-tune its response. The built-in 12dB / Octave Side Chain High-Pass Filter, sweepable from 20-250Hz, minimizes the limiter’s reaction to low frequencies, which tend to be more sustained in nature than high frequencies.

    The threshold control sets the maximum levels for your digital signal, and the variable release time constant alters the response characteristic to better fit different source material. To further push levels into the limiter, the class-A line amp stage is capable of adding 20dB of ultra-clean gain. The limiter may be used as a dual mono or stereo linked design via the Link switch, depending on the desired use.

    To achieve this, we refined our compound active release topology to enhance both the accuracy and musicality of the limiter response. The resulting limiter achieves both transparency and the capability of pushing the level of tracks or mixes without damage to the integrity of the source. 

    Mastering-Grade Conversion

    The MBC’s 24-bit/192kHz converters were developed after years of careful listening, and represent a further advancement of the design within the RMP-D8. The precision­ controlled internal clock’s minimal jitter and phase noise allow the converters to capture the complete performance of your music with a great degree of accuracy – simply put, the MBC creates an uncanny digital representation of your analog signals.

    “The first time I tracked vocals with the MBC it was like taking a blanket off the mic… It’s very quickly become my go-to converter for everything.”

    Brett Orrison – Jack White, Widespread Panic, Black Angels

    Make Connections 

    To connect into your interface or digital console, the MBC is equipped with AES, S/PDIF and TOSLINK outputs capable of simultaneous output to multiple destinations. The word clock output allows the MBC to act as high-end master clock for your entire setup, and the word clock input allows external sync to a separate master clock if desired. Finally, to seamlessly integrate the MBC into a multichannel conversion environment, four standard levels from -14dBFS to -20dBFS can be selected to accurately match your other converters. These Reference Level calibration standards are implemented with a superb degree of accuracy via high-precision resistors and relay-controlled stepped attenuation.

    Ultra-Precise Metering

    A pair of 22-segment meters provide extremely precise level metering of the input to the converter stage, utilizing a new design that represents the highest resolution LED metering in a Rupert Neve Designs product to date. For monitoring of the limiter’s gain reduction, there are 8-segment gain reduction meters designed to display transient reductions with a superb degree of accuracy. The level meters can be further customized with a 1-second or 3-second peak hold option.

    With legendary sound and a groundbreaking feature set, the Master Buss Converter is a new digital standard from the master of analog – and the ultimate tool for capturing your tracks, mixes, and masters.


    Selectable Analog Drive Paths

    The very best of class-A transformerless and custom transformer-coupled designs at the touch of a button.

    Transformer Path with Silk / Texture

    Add weight and punch with a dedicated custom inter-stage transformer before the converter. Silk / Texture allows you to dial in the harmonic content and drive saturation of this signal path.

    Class-A Transformerless Path

    Maximizes clarity and transparency of the input signal.

    Active Compound Release Analog Limiting

    Push your levels further with fewer artifacts than plug-ins, and introduce clip safety for tracking or broadcast.

    Side Chain HPF

    Tighten the response of your limiting with a 12dB / Octave SC HPF sweepable from 20Hz to 250Hz

    24-bit/192kHz Reference Conversion

    Unparalleled analog capture with precision clocking using top-of-the-line chips.

    Multi-Standard Connectivity

    Connect to any of your digital devices with AES, S/PDIF and TOSLINK all simultaneously available.

    Precision Clocking

    Maximum accuracy with minimal jitter and phase noise, able to operate as a master clock or sync from another master.

    Tech Specs

    XLR Line Input to AES3 Digital Output (Limiter Bypassed) – ZSOURCE= 40 Ω Balanced

    Input Impedance: 9.9 kΩ

    Common Mode Rejection @ 1 kHz: 105 dB typical

    Transformerless Path

    Frequency Response (20 Hz to 70 kHz):+/- 0.025 dB typical

    THD+N @1 kHz @ -2 dBFS (10 Hz – 22 kHz BW):0.0009% typical

    Noise (BW 10 Hz – 22 kHz):-108 dBFS typical

    Transformer Path

    Transformer Frequency Response (20 Hz to 70 kHz): +/- 0.1 dB typical

    THD+N @1 kHz @ -2 dBFS (10 Hz – 22 kHz BW): 0.002% typical

    Noise (BW 10 Hz – 22 kHz): -114 dBFS typical

    Limiter Specifications (Transformerless Path Selected) – ZSOURCE= 40 Ω Balanced

    Frequency Response (20 Hz to 70 kHz): +/- 0.1 dB typical

    Noise @ 0 dB Make-Up Gain (10 Hz – 22 kHz BW): -107 dBFS typical

    Noise @ +20 dB Make-Up Gain (10 Hz – 22 kHz BW): -97 dBFS typical


    Product Dimensions (W x D x H): 19” (48.3 cm) x 9” (22.9 cm) x 1.65” (4.2 cm)

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

    Shipping Weight: 10 lbs. (4.5 kg)