M21 Digital to Analog Converter

Bricasti M12 vs M21

The Bricasti M12 Source Controller and the M21 DAC share a similar design philosophy and several core technologies, but they are distinguished by their specific DAC pathways and their primary intended functions within an audio system.

DAC Architecture and Pathways

The most significant technical difference between the two units is the number of independent DAC circuits available:

• M12 (Two Pathways): The M12 features two independent DAC sections: a native Delta-Sigma PCM converter (utilizing Analog Devices chips) and a proprietary native 1-bit DSD converter.
• M21 (Three Pathways): The M21 is described as a "Swiss Army knife" because it adds a third pathway: a discrete 20-bit R2R Ladder DAC. This allows M21 users to choose between the punchy dynamics of Delta-Sigma or the "supple", analog-like timing of the R2R ladder for PCM playback, an option not present on the M12.

The Native DSD (NDSD) Implementation

Bricasti explains that the M12 was designed to solve a historical problem: most DSD converters actually convert the signal to PCM to perform basic functions like volume control or muting.

• Pure 1-Bit Conversion: Both the M12 and M21 utilize a native 1-bit DSD path that avoids PCM conversion entirely and is the purist approach.
• 10GHz Analog Switch: The M12 uses a very high-speed 10GHz analog switch to convert the DSD data stream directly into an analog waveform.
• Analog Management: Because DSD cannot be processed digitally (to change levels or mute) without being "messed with", the M12 utilizes a 90dB R2R digitally controlled analog resistor ladder to manage mutes, fades, and volume in the analog domain. This ensures that the DSD signal remains "pure" from the source to the output.

Functional Positioning: "Source Controller" vs. DAC

While both units can drive a power amplifier directly, their roles differ slightly:

• M12 as a Hub: The M12 is marketed as a Source Controller designed to integrate both digital and analog sources. It includes an extra set of analog inputs (for a phono stage or tape deck), making it a more comprehensive replacement for a traditional preamplifier.
• M21 as a Flagship DAC: The M21 is positioned as the flagship digital-to-analog converter, focusing on providing the user with every possible conversion technology (Delta-Sigma, R2R, and NDSD) in one chassis.

Sonic Characteristics and Performance

• M12 Sound: Reviewers note the M12 offers "tonal honesty" and "laser-focused resolution." When using the LAN interface, the sound is described as "leaner" and more accurate compared to USB, lifting "veils" to reveal deeper spatial cues and minute tonal inflections.
• M21 Sound: The M21 is praised for its three-dimensional spaciousness and "organic realism." Its R2R ladder DAC is specifically noted for its superior portrayal of natural reverb and decay compared to the Delta-Sigma path.

Physical Options and Pricing

Both units are available in "Platinum" editions, which feature noble metal finishes (nickel or platinum) that Bricasti claims actually improve the sound, making it more mellow and dimensional.

• The M12 is priced at approximately $16,500.
• The M21 is priced at approximately $16,500.
• The M12 Platinum is priced at approximately $19,000.
• The M21 Platinum is priced at approximately $19,000.

The Bricasti M12 and M21 overcome the historical limitations of DSD playback by utilizing a proprietary hardware architecture that avoids converting the 1-bit signal into PCM for processing. This is achieved through high-speed switching and managing all necessary signal adjustments—like volume and muting—in the analog domain.

Historical Limitations of DSD

Historically, 1-bit encoding (DSD) faced two primary hurdles:

• Noise and Distortion: Early attempts at direct DSD conversion were prone to high noise and poor distortion levels.
• Inability to Process Digital Signals: It is technically impossible to perform digital signal processing (DSP) functions, such as changing volume levels or muting a signal, directly on a 1-bit data stream.

To solve these issues, most industry converters use a Sigma-Delta technique, which converts the 1-bit DSD stream into multi-bit PCM to perform these functions before converting it back to analog. Bricasti designers argue this "messes with" the signal, requiring steep digital reconstruction filters that can degrade the sonic purity.

Bricasti's Solution: The Native 1-Bit Path

To achieve true native playback, the M12 and M21 employ a dedicated Native DSD (NDSD) path that keeps the 1-bit signal intact from the source to the final analog stage:

• 10GHz Analog Switch: Instead of a digital chip, the units use a very high-speed 10GHz analog switch to convert the DSD digital pulses directly into an analog waveform.
• Analog Signal Management: To handle volume control and muting without digital processing, Bricasti integrated a 90dB R2R digitally controlled analog resistor ladder. This allows the device to manage mutes, fades, and level adjustments entirely in the analog domain.
• DSP-Controlled Analog Logic: While a Sharc DSP is used, it does not process the musical bits; instead, it manages the timing of the analog switches and mutes to ensure seamless transitions between tracks or sample rates without generating noise.
• Gentle Analog Filtering: Because they avoid PCM conversion, these units do not require steep digital filters. Instead, they use a gentle, low-order analog low-pass filter to counter ultrasonic noise, which is considered more benign and musically natural.

Sonic Results

By overcoming these processing limitations, the M12 and M21 focus on the time-domain information of DSD, which Bricasti identifies as its "real magic". This approach results in a highly transparent sound that excels at portraying natural acoustics and three-dimensional soundstage accuracy.