Momentum C2 Preamplifier – new from Dan D’Agostino

The Momentum C2 Preamplifier is the newest preamp from Dan D’Agostino Master Audio Systems. Short for “Concept 2,” the Momentum C2 is a significant advancement on its predecessor, the Momentum HD Preamplifier. Expanding on the well-received framework of the Momentum Preamplifier platform, the Momentum C2 incorporates technical features and sonic attributes inspired by the flagship Relentless Preamplifier. Initially developed as the C4 in reference to its new Complementary Four-Circuit topology that makes up the unique input stage, the extent of the advancement within other sections of the component goes so far beyond its front-end circuitry that it calls for a name underscoring the magnitude of this new concept: Momentum C2 Preamplifier.

In the design of the Momentum C2, a dedicated audio chassis and separate power supply are utilised to achieve optimal mechanical and electrical isolation. These two chassis are interconnected using specialised electro-mechanical connectors integrated within each unit. Thirty-pin interlocking connectors, gold plated and capable of handling 20 amps, replace conventional wiring typically utilised in similar applications, reducing the risk of potential anomalies. This distinctive configuration guarantees complete isolation of the audio signal, both physically and electrically, from the power supply components. Furthermore, this physical segregation creates additional space for the optimisation of both power and audio circuitry. New for the Momentum C2 Preamplifier is enhanced digital capability. An LED display provides operational status and when equipped with the optional digital streaming module (DSM) metadata from digital music sources. A new two-way remote control featuring Bluetooth technology also provides this information in the palm of your hand.

Audio Circuitry Highlights

This circuitry represents an evolution from the utilisation of JFET transistors in D’Agostino preamplifiers, which debuted in the Momentum HD Preamplifier and has been further perfected in the Momentum C2 Preamplifier. The innovative Momentum C2 topology employs a distinct configuration of four JFET transistors arranged in a complementary, push-pull design, significantly enhancing input impedance. This enhancement 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 one megaohm, the JFETs themselves stand as the least noisy devices available. When integrated into the new C2 circuit arrangement, they effectively reduce the overall noise floor in this crucial stage.

The audio circuit topology starts with a completely unique, new discrete dual-complementary differential JFET input stage featuring a voltage input signal capability of an extraordinary thirty volts. The Momentum C2 Preamplifier’s front end is immune to source-related electrical issues. In normal operation, component heating can lead to performance and sonic degradation. Developed specifically for the Momentum C2 Preamplifier, a unique circuit maintains a stable bias so that temperature-related anomalies are offset, thus preserving performance during extended listening.

Utilising no negative feedback anywhere, core D’Agostino circuit concepts include a signal path that is fully complementary, direct coupled, and balanced from input to output, achieving a frequency response flat to 120 kHz.

All signal gain is realised in the current domain using proprietary multiple-output current mirrors with nearly thirty times the linearity of other designs. Executed with four-layer circuit boards for superior signal quality. The use of four-layer boards dramatically reduces distortion and propagation losses as compared to the more commonplace two-layer boards.

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.

In many preamplifier designs, volume control circuits are either overlooked or intentionally downplayed. However, this is not the case with the Momentum C2 Preamplifier. Each volume control is meticulously crafted using fourteen distinct components, ensuring the smoothest response and precise control over the military-grade, high-linearity solid-state switches and discrete precision resistors incorporated in the volume circuit. Consequently, the bandwidth and transient response of the Momentum C2 Preamplifier remain unaffected by the volume setting. Volume levels are elegantly displayed through the Swiss watch-inspired volume wands, or can be shown numerically, ranging from 0 to 99.

The seldom-seen tone control circuitry within the Momentum C2 Preamplifier remains entirely transparent in its operation, ensuring zero impact on the signal path when inactive. Concealed behind a discreet door on the front panel, a headphone jack featuring independent amplifier circuitry is also provided for added versatility.

Power Supply Highlights

Housed in a separate chassis to maximise isolation, power delivery duties are shared by individual transformers dedicated to the analogue and digital circuitry. Utilising a unique winding technology, initially employed in the Momentum M400 amplifier, this design delivers increased power output within the same footprint. 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, offering enhanced dynamics at both micro and macro levels. Also, present in the power supply chassis is an LCD display showing unit status, functions, and when equipped with the optional digital streaming module, metadata from equipped digital music sources.

Advanced Control

Housed in precision-machined aluminum and Delrin, the Momentum C2 Preamplifier’s remote control is a Bluetooth-enabled device, rechargeable via USB, boasting an ergonomic design and featuring an LCD screen. Offering bi-directional functionality, the remote mirrors the information on the Momentum C2 Preamplifier’s front panel onto its own display screen, including input, volume, and balance settings. Additionally, with the optional DSM installed, song metadata is also shown on the display. Optional Digital Streaming Module (DSM) The Momentum C2 Preamplifier marks a milestone as the first D’Agostino Momentum
preamplifier to offer an optional Digital Streaming Module. This digital enhancement expands connectivity options for digital legacy sources and introduces premier streaming capabilities.

Easily upgradeable in the field, the DSM incorporates SPDIF coaxial, Optical, USB-B, RJ45, and Wi-Fi network inputs. To ensure seamless playback of high-resolution network content without latency, it supports 10/100/1000 Gigabit Ethernet. Tailored iOS apps facilitate effortless control of music collections, streaming content, and unit functions. Native integration with subscription streaming services like Tidal, Qobuz, and Spotify is supported within the app, with additional compatibility for Tidal Connect. Furthermore, with appropriately encoded files, standard MQA decoding is enabled. For users preferring alternative music management, Roon Ready certification will also be available. Capable of handling the highest resolution sources available today, the Momentum C2 decodes PCM signals up to 32 bit/384 KHz and DSD signals up to DSD256 (11.2MHz) natively. Recognising the crucial role of the analogue section in digital music performance, internal balanced connections ensure optimal signal transfer to the C2 circuitry stage, leveraging the full potential of the preamplifier’s power and analog circuitry across its two chassis.

“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,” stated Dan D’Agostino, Co-Founder and Chief Engineer.
Available in silver, black, or custom painted finishes, every Momentum C2 Preamplifier is handbuilt and individually tested in D’Agostino’s Arizona factory by our team of technicians and craftsmen.
The UK RRP is £59,998 inc. VAT, with the optional digital streaming module adding £11,398 to the price.
As with all Dan D’Agostino Master Audio Systems products, the Momentum C2 Preamplifier is brought to the UK by Absolute Sounds.
For more information on Dan D’Agostino Master Audio Systems and its products, please visit
www.dandagostino.com