HiBy RS2 II: Compact R2R DAP for $439

The launch of the HiBy RS2 II was announced today, along with some of its specifications. The second-generation RS2 features DARWIN III, an updated version of HiBy’s R2R DAC architecture that incorporates hardware and software improvements. This makes the RS2 II the most compact DAP to feature the same technology found in the RS8 II, HiBy’s flagship model.

Update (September 23): The HiBy RS2 II is now available from HiBy’s online store. The product specifications have been updated.

The RS2 II is the most compact and affordable DAP with an R2R DAC on the market

With the launch of the RS2 II, HiBy will offer the most compact and affordable DAP with an R2R DAC on the market. The new digital audio player incorporates the third generation of HiBy’s DARWIN R2R DAC architecture into a compact chassis.

With a suggested retail price of US$439, the HiBy RS2 II is more affordable than the FiiO M33 R2R. HiBy’s DAP is also more compact than FiiO’s model and likely has dimensions similar to those of the first-generation RS2, released in 2022.

The second-generation RS2 offers nearly twice the output power of its predecessor

Compared with the first generation, the RS2 II offers nearly twice the output power. While the RS2 delivers 320 mW through its 4.4 mm balanced output, the RS2 II delivers 630 mW under the same conditions.

Power has also increased at the 3.5 mm single-ended (SE) output, although to a lesser extent. The RS2 II delivers 165 mW through its 3.5 mm output, compared with 125 mW for the first-generation DAP.

The RS2 II’s sound has improved significantly compared with the first generation

According to “Lao Huang,” a user of the Chinese social media platform Weibo, the RS2 II offers substantially improved sound compared with the first generation. He stated:

“In my opinion, the overall performance represents a substantial improvement over the first-generation RS2. I think it is a good choice for listening to pop music and female vocals.”

Lao Huang further commented on the RS2 II’s sound:

“The sound is very smooth, with a slightly warm signature. The midrange is delicate and full-bodied, the bass is moderate in quantity, and the treble is smooth.”

The RS2 II features an improved display

The RS2 II introduces several display improvements over the original RS2 (OG). It now features a 3.5-inch display, representing a 45% increase in size. The resolution has also increased from 480 × 360 to 480 × 800 pixels, improving the sharpness of the displayed images.

HiBy RS2 buttons and connections

The RS2 II introduces several changes to its connections compared with the first generation. Instead of a dedicated line-out connection, the headphone outputs also serve this function. However, the headphone outputs remain at the top of the DAP rather than the bottom.

The bottom of the RS2 II houses the two microSD card slots and the USB-C port.

On the side, there is a volume control knob and three buttons for controlling music playback.

Two microSD card slots

As with the first generation, HiBy has retained two microSD card slots in the RS2 II. Each slot supports microSD cards of up to 2 TB, allowing the DAP to store up to 4 TB of music.

Bidirectional USB port

The RS2 II can function as both a USB DAC and a digital transport because its USB port supports data transmission and reception.

No Bluetooth

For those considering using the RS2 II with Bluetooth headphones, the DAP supports neither Bluetooth transmission nor reception.

No music streaming

Note that the HiBy RS2 II does not include music streaming apps. It is intended exclusively for local playback of music files. For this reason, it runs HiByOS in its most basic form, which does not support either Qobuz or Tidal over Wi-Fi.

HiBy RS2 II: Specifications

General Specifications

• Amplification: 4 × Texas Instruments (TI) OPA1612 operational amplifiers + 4 × Texas Instruments (TI) OPA1622 operational amplifiers
• Bluetooth: None
• Chassis material: Aluminum alloy
• Color: Green
• DAC chip: DARWIN III R2R, developed in-house by HiBy
• Digital connections: USB-C and coaxial
• Dimensions: 91.95 × 62.05 × 18.6 mm
• Display: 3.5-inch touchscreen with a resolution of 480 × 800 pixels
• Headphone outputs: 3.5 mm single-ended (SE) and 4.4 mm balanced
• Line outputs (LO): 3.5 mm single-ended (SE) and 4.4 mm balanced
• Operating system (OS): HiByOS (Linux-based)
• SoC: Lumissil X1600E
• Storage: Two microSD card slots, supporting up to 2 TB per card
• Weight: 156 g
• Wi-Fi: None

Battery Specifications

• Battery capacity: 3500 mAh / 3.8 V
• Battery life using the 3.5 mm single-ended (SE) output: 9 hours
• Battery life using the 4.4 mm balanced output: 8 hours
• Charging: 5 V / 2 A, 5 V @ 200 mA
• Standby battery life: 32 days

General Audio Specifications

• Native decoding capability: PCM up to 384 kHz/32-bit, DSD256, and MQA 8×
• Supported audio file formats: MP3, WAV, APE, FLAC, DSF, DFF, ISO, CUE, WMA, OGG, AAC, OPUS, AIFF

3.5 mm Single-Ended (SE) Headphone Output Specifications

• Voltage swing: 2.2 Vrms
• Maximum output power per channel: 172.5 mW
• Rated output power per channel: 165 mW
• Minimum distortion: 0.003
• Noise floor: 1.5–2.6 μV
• Signal-to-noise ratio (SNR): 119 dB
• Dynamic range: 105 dB
• Crosstalk rejection (channel separation): 70 dB
• Frequency response (−3 dB): 20–40 kHz

4.4 mm Balanced Headphone Output Specifications

• Voltage swing: 4.5 Vrms
• Maximum output power per channel: 411.8 mW
• Rated output power per channel: 630 mW
• Minimum distortion: 0.003
• Noise floor: 2.3–4.5 μV
• Signal-to-noise ratio (SNR): 120 dB
• Dynamic range: 105 dB
• Crosstalk rejection (channel separation): 105 dB
• Frequency response (−3 dB): 20–40 kHz

3.5 mm Single-Ended (SE) Line Output Specifications

• Voltage swing: 2 Vrms
• Minimum distortion: 0.0008
• Noise floor: 2 μV
• Signal-to-noise ratio (SNR): 119 dB
• Dynamic range: 105 dB
• Crosstalk rejection (channel separation): 105 dB
• Frequency response (−3 dB): 20–40 kHz

4.4 mm Balanced Line Output Specifications

• Voltage swing: 4 Vrms
• Minimum distortion: 0.0007
• Noise floor: 3.5 μV
• Signal-to-noise ratio (SNR): 120 dB
• Dynamic range: 105 dB
• Crosstalk rejection (channel separation): 108 dB
• Frequency response (−3 dB): 20–40 kHz

What is included in the HiBy RS2 II box?

The following items are included in the HiBy RS2 II box:

• RS2 II DAP
• USB-C to USB-C cable
• Synthetic leather case
• USB-C to USB-A adapter
• USB-C to coaxial cable
• Quick start guide

Release date, pricing, and availability

The HiBy RS2 II is now available internationally for US$439 through HiBy’s online store.