R-2R DAC vs Sigma-Delta: Which Digital Audio Player (DAP) Sounds Better?
Feb 14, 2025
A Full Discrete R-2R DAC is a type of digital-to-analog converter (DAC) that uses a network of discrete resistors to convert a digital signal into an analog signal. It is called R-2R because it utilizes only two values of resistors-one with resistance R and another with resistance 2R-arranged in a ladder-like structure.
In a Full Discrete R-2R DAC, each resistor is separately implemented using high-precision discrete components rather than integrated circuits (ICs). This gives designers control over resistor quality, matching, and layout, leading to potential improvements in sound quality.
Difference Between Full Discrete R-2R and Other DAC Types
| Feature | Full Discrete R-2R DAC | IC-Based DAC (Sigma-Delta, Multibit, etc.) |
|---|---|---|
| Design | Uses discrete resistors and analog switches | Uses integrated circuits (ICs) with DSP |
| Sound Character | More natural, analog-like, smooth sound | Often detailed but can sound processed |
| Linearity & Accuracy | Requires precise resistor matching for accuracy | Uses internal digital processing to correct errors |
| Dynamic Range & Noise | Can achieve high dynamic range if built properly | High-end IC DACs have excellent noise performance |
| Complexity & Cost | Expensive, difficult to manufacture | More affordable and widely available |
| Upgradeability | Can fine-tune components for better performance | IC-based DACs are fixed designs |
Advantages of Full Discrete R-2R DACs
- Natural Sound – Many audiophiles prefer the smooth and organic sound of R-2R DACs.
- No Oversampling or Digital Filtering - Unlike sigma-delta DACs, R-2R DACs can work without oversampling, preserving time-domain accuracy.
- Customization & Upgradability - Designers can hand-pick resistors, power supplies, and circuit layouts to optimize sound.
Disadvantages of Full Discrete R-2R DACs
- Expensive & Difficult to Manufacture - High precision resistor matching is required to maintain accuracy.
- Performance Challenges - Poorly implemented R-2R DACs can suffer from high Total Harmonic Distortion (THD).
- Size - Requires more space than integrated DACs.
Digital Audio Players (DAPs) Featuring Full Discrete R-2R DACs
Luxury & Precision P6 Pro
- Description: The P6 Pro utilizes a discrete R-2R DAC architecture equivalent to 16 PCM1704K chips, aiming to deliver high-fidelity audio.
- Features:
- 3.5-inch touch-sensitive IPS screen
- 64GB built-in storage with microSD expansion
- Supports various audio formats, including APE, AAC, ALAC, FLAC, WAV, MP3, WMA, DFF, DSF, AIFF, and SACD-ISO
- Outputs: 4.4mm balanced and 3.5mm unbalanced
- Bluetooth 5.0 with LDAC, aptX HD, aptX, AAC, and SBC support
- Review: Head-Fi Review
HiBy RS6
- Description: The RS6 is HiBy's first portable R-2R DAP, featuring their proprietary Darwin audio architecture, which includes a discrete R-2R ladder DAC.
- Features:
- Android-based operating system
- 4.97-inch touchscreen display
- Dual card slots for expandable storage
- Multiple output options, including 4.4mm balanced and 3.5mm single-ended
- Wi-Fi and Bluetooth connectivity
- Review: SoundNews Review
HiBy RS8
- Description: Building upon the RS6, the RS8 is HiBy's flagship DAP featuring an upgraded discrete R-2R DAC design for enhanced audio performance.
- Features:
- High-resolution audio support
- Enhanced internal components compared to the RS6
- Requires a break-in period of at least 50 to 100 hours for optimal performance
- Product Information: MusicTeck Product Page
HiBy RS2
- Description: The HiBy RS2 is a compact digital audio player featuring a full discrete R-2R DAC with HiBy's proprietary Darwin audio architecture.
- Features:
- Darwin Audio Architecture: Discrete R-2R resistor ladder network with linearity compensation, adjustable FIR filter, harmonic controller, and Non-Oversampling (NOS) / Oversampling (OS) modes.
- HiByOS PureAudio Version: A custom operating system optimized for pure audio playback.
- Compact Design: 2.45-inch touchscreen, 90.3 x 64.8 x 18.8 mm size, and 158g weight.
- Dual MicroSD Card Slots: Supports up to 2TB per slot.
- Multiple Output Options:
- 3.5mm Single-Ended Phone Output
- 4.4mm Balanced Phone Output
- 3.5mm Line Out
- USB DAC Functionality: Can function as a USB DAC and supports coaxial digital output.
- Battery Life: 3500mAh battery provides ~10 hours of playback, ~3-hour charge time.
- Sound Signature: Smooth, organic, spacious, and highly musical.
- Review: Headfonics Review
Cayin R01 Module for N6ii
- Description: The R01 is a discrete R-2R ladder DAC/amp module designed for the Cayin N6ii DAP, offering an alternative to traditional DAC architectures.
- Features:
- All-discrete resistor R-2R ladder DAC
- Compatible with the N6ii DAP, allowing users to switch between different DAC/amp modules
- Review: Twister6 Review
Conclusion
A Full Discrete R-2R DAC prioritizes natural sound quality and analog smoothness over modern high-precision, high-resolution DAC chip solutions. While IC-based DACs are efficient and cost-effective, Full Discrete R-2R DACs remain a preferred choice for audiophiles seeking a unique, non-digital sonic signature.
These DAPs represent the latest in Full Discrete R-2R technology, catering to those who appreciate high-fidelity, analog-like audio reproduction in a portable form.