RME High-End USB/AD/DA Converter and Headphone Amplifier ADI2ProFS

RME's anniversary reference AD/DA converter is:

• A high-end AD/DA converter in professional studio quality
• A double headphone amplifier in true high-end quality
• A USB DAC like no other - the most versatile and capable one
• A high-end AD/DA frontend and headphone amp for iPad / iPhone
• A multi-format converter (AES, SPDIF, ADAT) with monitoring function
• A DSD record and playback solution
• An AD/DA frontend for audio measurement at up to 768 kHz sample rate

Ultra-fidelity PCM/DSD 768 kHz AD/DA Converter

As the most flexible converter available, the ADI-2 Pro offers balanced/unbalanced analog I/Os, double Extreme Power headphone outputs, SteadyClock III, 4-stage hardware input and output level control, DSP-based signal processing, external power supply operation, Class Compliant USB compatibility, sample rates up to 768 kHz as well as DSD record and Direct DSD playback (256 / 11.2 MHz).

Analog or Digital - Options Galore

The ADI-2 Pro includes two servo-balanced analog inputs on combo XLR / TRS jacks, two separate balanced and unbalanced outputs on XLR and TS, two stereo Extreme Power headphone outputs on the front, an optical SPDIF I/O that also understands ADAT, and coaxial SPDIF (RCA) and AES I/O (XLR) via an included breakout cable. This universal set of I/O options offers superior quality and flexible connectivity to those who take a no-compromise approach to audio.

The USB 2.0 port is fully Class Compliant (UAC 2) for connection with compatible iOS devices, and is also used for firmware updates. Including an external switched power supply with lockable connector, the ADI-2 Pro can be easily powered from battery, opening up mobile applications as well as galvanically isolated use cases.

As a computer interface the ADI-2 Pro offers a stereo (2 in / 2 out) and a multichannel mode (6 in / 8 out). Compatibility with Mac OS X comes right out of the box. Under Windows the ADI-2 Pro uses RME's MADIface series driver, for full WDM and ASIO compatibility and highest performance.

Perfect Sound Capture and Reproduction

Aiming for the absolute reference sound, any detail in the ADI-2 Pro is special and has its own story. The main PCB is an extraordinary 10 layer design with custom copper thickness, guaranteeing finest undisturbed sound as well as ample but separated power for the phones outputs. Internal power supply stages and precise regulators use a super-low-noise design to not degrade performance through the power rails. Selected SoundPlus operational amplifiers maintain highest SNR, lowest THD and high slew rate under all conditions. The whole analog circuit design is fully symmetrical and balanced throughout - and DC-coupled. The only capacitors in the signal path perform DC protection at the analog input sockets, and have been carefully selected to avoid any sonic impact.

The 4-channel AD-converter, supporting 786 kHz sample rate and DSD recording, is used in a dual mono design, with 3 dB improved signal to noise ratio. Two premium DACs are used for two separate stereo outputs. Internal audio processing like EQs, Crossfeed and spectral analysis, is done by a high performance DSP with 2.17 Giga FLOPS (2882 MIPS), delivering enough computing power to work even at 768 kHz sample rate.

For easy operation a high quality Sample Rate Converter has been added, switchable to the AES or SPDIF input, solving any clocking problem between those. And RME’s latest SteadyClock III technology ensures perfect jitter reduction and stable clocking, no matter if internal or external clocks are used.

High Resolution Display Operation

RME have incorporated many unique features, not found on any comparable devices, like 5-band parametric EQs for fully individual phones compensation, adjustable Bass/Treble controls with quick access, a binaural crossfeed function, adjustable loudness filter, selectable AD/DA filters, four discrete I/O reference levels, auto reference level setting, auto balanced phones mode, and many more. The display is not only used to control the unit, but also shows warning and guidance messages.

Professional features such as M/S Processing, stereo width and phase reversal up to full control and storage of all settings are included, as well as RME’s famous Spectral Analyzer, a 30-band biquad filtered analysis tool offering unprecedented musical visualization, perfectly complementing the high-resolution IPS display.

Extreme Power Headphone Outputs

There is no use in boasting about -110 dB THD, when such values are not available in real world operation - for example when a 32 ohm headphone is connected. RME's engineers therefore designed a new headphone output stage that brings the full performance of the premium DAC to the phone jack - even when using low impedance headphones. The Extreme Power design excels with 0.1 Ohm output impedance, a maximum output level of +22 dBu, and a maximum output power of 1.5 Watts - per channel! The two, fully separated stereo headphone outputs deliver the same 120 dBA SNR performance as the line outputs, for a full hum and noise free listening experience. THD is far below -100 dB (0.001%) even at full power, for the most clear and detailed soundstage possible. The Extreme Power design also incorporates current limiting, power surveillance, overload detection and DC protection. A low power mode and a high power mode are provided, for a perfect match from IEM up to planar.

Having two stereo outputs, balanced headphone operation is possible. As RME's engineers were not satisfied with the existing techniques they developed a new Advanced Balanced mode for the ADI-2 Pro, that removes most limitations of standard balanced operation, and turns this mode into a a fully new experience. The exclusive Advanced Balanced mode delivers a balanced signal path from the DAC straight to the phone, with 3 dB gain in Signal to Noise Ratio, smoothed out deviations in components, optimized frequency response, super low output impedance (0.2 Ohms), and a maximum output level of +28 (twenty eight) dBu.

The Anniversary Converter

The ADI-2 Pro is RME’s reference AD/DA converter, USB DAC, USB interface and headphone amp. It’s numerous use cases make it an ideal choice in many fields, from the home user appreciating innovative solutions offering highest sound quality, the studio owner asking for reference AD/DA conversion, the Hi-Fi enthusiast demanding a flexible yet high-end headphone amplifier, up to the industry using the portable device as front-end for measurement systems. 20 years of RME - cumulated into a precious unit, that once heard and used one will never give away. Promised.

Femtoseconds for clocking

With the SteadyClock FS, the ADI-2 Pro FS features the latest clock and jitter rejection technology from the recently introduced ADI-2 DAC. Based on a femtosecond clock – a femtosecond is one quadrillionth of a second – SteadyClock FS reduces the intrinsic jitter of the ADI-2 Pro FS to a new all-time low.

Furthermore, the ADI-2 Pro FS also features the AutoDark mode from the ADI-2 DAC. With this, users can deactivate all illuminated elements of the device if necessary – except of the standby button, which in contrast to the ADI-2 DAC, is always illuminated on the ADI-2 Pro FS. In this way, studio users receive permanent feedback about the on/off status of their converter. The lighting is reactivated by pressing any button or turning an encoder.

Bit Test

A bit test is used to check the playback path for unwanted changes in the playback data. Playback software can cut bits, add dither, or change the level - without these changes becoming noticed easily. A poorly programmed driver can manipulate bits, and a playback hardware could be both badly designed and defective (hanging bits, swapped bits). Even such features as proper channel assignment, left/right synchronicity and polarity can be tested by a well-made bit test.

With a bit test, such errors can be detected and - more importantly - excluded.

Bit Test Audio files (download)