Audio-GD R-29: A high-performance single-ended preamplifier and headphone amplifier with an integrated R2R DAC. It features Coaxial RCA, HDMI I2S, and USB inputs supporting up to 384kHz/32Bit and DSD64–512. The R2R DAC offers NOS and selectable 2x, 4x, and 8x oversampling modes for tailored sound. With RCA line output and two powerful headphone outputs delivering up to 3800mW at 25Ω, plus switchable gain modes (+12dB / +22dB), the R-29 combines versatility, precision, and musicality in one elegant unit.

Specifications:

Inputs: 
1x USB-B
1x HDMI I2S
1x Coaxial
Outputs    1x Stereo RCA
2x Jack 6.35mm

Signal-to-noise ratio (SNR): > 115dB

Total harmonic distortion more noise (THD+N): < 0.015%

Gain: 
L : +12DB
H : +22DB

Channel balancing: < 0.05dB

Frequency response: 20Hz - 20KHz (< -0.5dB)

Output Level: 
Headphone output : 10V RMS
Variable preamp output : 10V RMS

Fixed DAC output : 2.5V RMS
Headphone output power    3800mW @ 25Ω
2400mW @ 40Ω
950mW @ 100Ω
330mW @ 300Ω
165mW @ 600Ω

Output impedance: 
Headphone : 1Ω
DAC / Preamp : 5Ω

Input sensitivity: 0.5Vp-p (75 Ohms, Coaxial)

Supported sampling rates: 
USB / I2S : PCM 32bit 384kHz / DSD512
Coaxial : PCM 192kHz