Dan D'Agostino Master Audio Systems says the C2 Preamplifier, or Concept 2, has been designed to be a "significant advancement on its predecessor," the Momentum HD Preamplifier.

We are told that the 33.1 kg Momentum C2 incorporates technical features and sonic attributes inspired by the flagship Relentless Preamplifier. Firstly, there is a dedicated audio chassis and separate power supply to achieve optimal mechanical and electrical isolation, resulting in a claimed 105 dB, unweighted signal-to-noise ratio. These two chassis are interconnected using specialised electro-mechanical connectors integrated within each unit.

The thirty-pin interlocking gold-plated connectors can handle 20 amps and replace conventional wiring typically used in similar applications, reducing the risk of potential anomalies. The high-end audio brand states this guarantees complete physical and electrical isolation of the audio signal from the power supply components. Furthermore, this physical segregation creates additional space for optimising both power and audio circuitry.

Here, a distinct configuration of four JFET transistors arranged in a complementary, push-pull design is said to significantly enhance input impedance, which serves as a foundation for the entire preamplifier topology, effectively isolating it from the prevalent extraneous noise in audio systems.

With an input impedance surpassing 1 megaohm, the JFETs themselves are the least noisy devices available. Moreover, when integrated into the new C2 circuit arrangement, they effectively reduce the overall noise floor in this crucial stage. D'Agostino claims a distortion measurement of <0.002%, 20 Hz to 20 kHz (full output).

The audio circuit topology starts with a new discrete dual-complementary differential JFET input stage featuring an extraordinary 30 volts of voltage input signal capability. Additionally, a unique circuit maintains a stable bias to offset temperature-related anomalies, thus preserving performance during extended listening.

Eschewing any negative feedback in the circuitry, D'Agostino circuit concepts include a fully complementary signal path design, direct-coupled and balanced from input to output, achieving a claimed frequency response flat to 120 kHz. The brand also highlights the use of four-layer circuit boards resulting, they say, in superior signal quality, dramatically reducing distortion and propagation losses compared to the more commonplace two-layer boards.

Naturally, analogue and digital circuit elements, including ground planes, are isolated from each other. Where necessary, digital control signals are optically coupled to analogue circuits. The signal-switching relays are hermetically sealed and use gold-plated contacts for maximum signal integrity.

Special consideration has also been given to the C2's volume circuitry, with each volume control "meticulously crafted using 14 distinct components," ensuring precise control over the military-grade, high-linearity solid-state switches and discrete precision resistors incorporated in the volume circuit. The upshot here is that the volume setting does not affect the bandwidth and transient response of the Momentum C2 Preamplifier. Volume levels are elegantly displayed through the Swiss watch-inspired volume wands or can be shown numerically, ranging from 0 to 99.

Finally, a headphone jack featuring independent amplifier circuitry is concealed behind a discrete door on the front panel, offering further versatility.

D'AGOSTINO MOMENTUM C2 DSM

If you wish to add digital connectivity to the D'Agostino C2, you can specify the optional Digital Streaming Module (DSM). This module incorporates SPDIF coaxial, Optical, USB-B, RJ45, and Wi-Fi network inputs and decodes PCM signals up to 32-bit/384 KHz and DSD signals up to DSD256 (11.2MHz) natively. The DSM supports 10/100/1000 Gigabit Ethernet to ensure seamless playback of high-resolution network content without latency.

Apple users can access the iOS app to control music collections, streaming content, and unit functions. The app supports native integration with subscription streaming services such as Tidal, Qobuz, and Spotify and is also compatible with Tidal Connect and MQA.

Thankfully, if you are an Android user or already have a Roon account, Roon Ready certification will also be available.

MOMENTUM C2 POWER SECTION

Meanwhile, the power supply is housed in a separate chassis to maximise isolation, where power delivery duties are shared by individual transformers dedicated to the analogue and digital circuitry. Furthermore, we are informed that its internal circuitry addresses RF noise from the AC  power line, compensating for asymmetric power waveforms and DC on the mains.

Capitalising on the augmented power supply capability, the output stages operate at a 36% higher voltage, which should translate to enhanced dynamics at both micro and macro levels.

The power supply chassis also houses an LCD display showing unit status and functions. Also, if you have opted to add the digital streaming module, you get a metadata readout from equipped digital music sources.

The Momentum C2 is bundled with a remote control housed in precision-machined aluminium and Delrin. The Bluetooth-enabled device is rechargeable via USB and boasts an ergonomic design and an LCD screen that mirrors the Momentum C2 Preamplifier's front panel information.

Dan D'Agostino, Co-Founder and Chief Engineer, told StereoNET:

The Momentum C2 Preamplifier represents a significant leap forward for our Momentum platform. Drawing insights from our pioneering work on the Relentless Preamplifier, the  Momentum C2 topology achieves a level of transparency that is unparalleled in preamplification but for its bigger brother.

The Momentum C2 Preamplifier, available in silver, black, or custom-painted finishes, has a UK RRP of £59,998. The optional digital streaming module costs £11,398.

Visit Dan D'Agostino Master Audio System for more information