iBasso D18 Crotalus

Portable R2R DAC and Headphone Amplifier

• Up to 1,750 mW of output power with an external power supply
• In-house-developed R2R DAC (R2R Ultra)
• Headphone outputs: 4.4 mm balanced and 3.5 mm single-ended, plus line outputs in both formats
• Native decoding via USB: PCM up to 768 kHz and DSD512
• Aluminum alloy chassis with stainless steel back panel and 1.3-inch OLED display
• 9-hour battery life

The Return of the R2R

iBasso returns with a new portable R2R DAC and amplifier: the D18 Crotalus.

At its heart is the in-house developed R2R DAC in the R2R Ultra configuration.

Power for high-end headphones

The D18 Crotalus delivers up to 1,750 mW of output power when powered by the external power supply. At the balanced 4.4-mm output, 1,530 mW is available at 32 Ω with high gain when running on battery power; with the external 12-V DC power supply, it’s 1,750 mW at 32 Ω, in each case with distortion below 0.5%. Depending on the gain setting, the balanced output reaches 4.2 V RMS (low), 6.2 V RMS (medium), or 7.6 V RMS (high). The 3.5-mm single-ended output delivers 2.1 V RMS, 3.1 V RMS, and 3.8 V RMS across the three levels and provides 440 mW into 32 Ω in both battery and AC power modes.

High-Level Performance Metrics

The balanced headphone output achieves a dynamic range and signal-to-noise ratio of 128 dB each, channel separation of 142 dB, and a THD+N of −95 dB (0.0017%). The output impedance is 0.7 Ω, and the noise level is 1.5 µV RMS. At the 3.5-mm single-ended output, the dynamic range and signal-to-noise ratio are 123 dB, the channel separation is 129 dB, and the THD+N is −93 dB (0.002%). Both outputs cover a frequency response from 10 Hz to 40 kHz (−1 dB).

Connections and Decoding

For headphones, a 3.5-mm single-ended output and a balanced 4.4-mm output are available. The line outputs are also available in both variants: 3.5 mm single-ended and 4.4 mm balanced. Via USB, the D18 Crotalus natively decodes PCM up to 768 kHz and DSD512. The coaxial input supports PCM up to 768 kHz and DoP256, while the optical input supports PCM up to 192 kHz and DoP128.

Housing, Controls, and Battery

The housing is made of aluminum alloy with a stainless steel back panel. A 1.3-inch OLED display shows the device status; the D18 Crotalus is controlled via a multifunction knob and a power switch. The battery provides 9 hours of runtime and charges in 2.5 hours. Charging is via USB-C at 5 V/2 A or via DC at 12 V/1.5 A.

Technical Specifications

DAC: Proprietary R2R Ultra

Housing Material: Aluminum alloy with stainless steel back panel

Dimensions: 140.4 × 75.3 × 18.8 mm

Weight: 271 g

Display: 1.3-inch OLED

Headphone outputs (PO): 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

Controls: Multifunction knob and power switch

Charging: USB-C at 5 V/2 A or DC at 12 V/1.5 A

Battery

Battery life: 9 hours

Charging time: 2.5 hours

General Audio Specifications

Native decoding via USB: PCM up to 768 kHz and DSD512

Native decoding via coaxial input: PCM up to 768 kHz and DoP256

Native decoding via optical input: PCM up to 192 kHz and DoP128

Balanced 4.4-mm headphone output

Output voltage at low gain: 4.2 V RMS

Output voltage at medium gain: 6.2 V RMS

Output voltage at high gain: 7.6 V RMS

Maximum output power in battery mode: 1,530 mW into 32 Ω, high gain, distortion < 0.5%

Maximum output power with external 12-V DC power supply: 1,750 mW into 32 Ω, high gain, distortion < 0.5%

THD+N: −95 dB (0.0017%) at 1 kHz; AES17 20K, A-weighted, 300-Ω load

Dynamic range: 128 dB; AES17 20K, A-weighted

Signal-to-noise ratio: 128 dB; AES17 20K, A-weighted

Channel separation: 142 dB

Frequency response: 10 Hz to 40 kHz (−1 dB)

Output impedance: 0.7 Ω

Noise level: 1.5 µV RMS

3.5-mm single-ended headphone output

Output voltage at low gain: 2.1 V RMS

Output voltage at medium gain: 3.1 V RMS

Output voltage at high gain: 3.8 V RMS

Maximum output power in battery mode: 440 mW into 32 Ω, high gain, distortion < 0.003%

Maximum output power with external 12-V DC power supply: 440 mW into 32 Ω, high gain, distortion < 0.5%

THD+N: −93 dB (0.002%) at 1 kHz; AES17 20K, A-weighted, 300-Ω load

Dynamic range: 123 dB; AES17 20K, A-weighted

Signal-to-noise ratio: 123 dB; AES17 20K, A-weighted

Channel separation: 129 dB

Frequency response: 10 Hz to 40 kHz (−1 dB)