Dan D’Agostino unveils the Momentum C2 Preamplifier, priced at $62,000

The Momentum C2 features a dual-chassis design, consisting of a primary preamplifier and a separate external power supply. These two components are linked by a thirty-pin gold-plated cable that can support currents of up to 20 amps. This innovative design ensures complete separation of the audio signal from the power supply, minimizing interference. The preamplifier circuit incorporates JFET transistors, which were initially introduced in the Momentum HD preamp. In the Momentum C2, the topology employs a discrete arrangement of four JFET transistors configured in a complementary push-pull setup, significantly improving input resistance. This design effectively reduces noise in the audio signal, with an input impedance that exceeds 1 MΩ.

Dan D’Agostino Momentum C2 preamp

The audio circuit design features a newly developed discrete double-complementary differential input stage utilizing JFETs, capable of handling a voltage input signal of up to 30V. To prevent sound quality deterioration due to component heating during regular use, the Momentum C2 incorporates a thermal management system that maintains a stable temperature, ensuring consistent audio performance throughout prolonged listening periods. The circuit operates without any negative feedback, providing a balanced signal path from input to output and achieving a flat frequency response that extends to 120KHz. Utilizing four-layer circuit boards enhances signal integrity, significantly minimizing distortion and losses when compared to traditional two-layer boards. The analog and digital circuits are designed to be independent and isolated from one another, including their grounding systems. When necessary, digital control signals are transmitted to the analog circuits via optical coupling. Additionally, the signal switching relays are hermetically sealed and feature gold-plated contacts for optimal performance.

The volume circuit within the preamplifier has been carefully designed with 14 discrete components, providing a smooth response characterized by high linearity solid-state switches and precision discrete resistors. As a result, the bandwidth and transient response of the Momentum C2 preamplifier are not influenced by the volume setting. Volume levels are displayed on the “Swiss clock” located on the front panel of the preamplifier, ranging from 0 to 99. Additionally, there is a headphone jack concealed under a cover on the front, which connects to an independent headphone amplifier. The power supply, housed in its own chassis, features transformers specifically allocated for the analog and digital circuits, utilizing a specialized winding to enhance output VA.

The Momentum C2 is a creation of two chassis, the main preamplifier and its external power supply.

The internal circuitry of the power supply manages RF interference originating from the AC power line, effectively addressing unbalanced waveforms and the DC component present in the mains. Additionally, the power supply features an LCD display that indicates the status and operational functions of the unit. The Momentum C2 remote control is constructed from aluminum and Delrin, equipped with a rechargeable battery that charges via USB and connects to the system through Bluetooth. It includes an LCD screen that replicates the information displayed on the preamplifier’s front panel, such as input selection, volume, and balance adjustments.

Furthermore, when the optional DSM (streamer) is integrated, song metadata is displayed as well. This optional streamer unit (DSM) is capable of accessing Tidal, Qobuz, and Spotify, and it also features support for Tidal Connect. Additionally, it includes MQA decoding and is certified as Roon Ready. The unit can decode PCM signals up to 32 bit/384 KHz and DSD signals up to DSD256 (11.2 MHz) natively. The preamplifier is offered in silver, black, or custom-painted options. The starting price for the Momentum C2 is $62,000, which increases to $73,000 with the optional streamer included.