RD-3 is available in 2 versions:
without AD1865*
139 €
with AD1865N-J
169 €
RD-3 assembled : 259 €
AD Labs presents the new RD-3 D/A converter. Instead of relying only on spdif receiver pll (CS8416) for jitter reduction like concurrent offerings, the RD-3 features a custom reclocking technique (ART) built with Xilinx programable logic, external analog loop and MAX9485 low jitter master clock generator. This stage perfectly locks on the clocks generated by CS8416 and delivers low jitter output, while keeping perfect audio data integrity. The reclocked signals are routed directly into AD1865 which is well known as one of the best R2R dac available. A zero-feedback, fully discrete i/v converter delivers pure analog quality at the output.
Details:
input frequencies : 32, 44.1, 48, 88.2, 96, 192 Khz
number of inputs : 2 (optical, coaxial)
S/N ratio: 102 dB
THD : 0,06%
IMD : 0,04%
Low impedance output (30 ohms)
Bandwidth : 20 Hz - 20 Khz, +/- 0.5 dB
Featuring ART - Audiokitlabs Reclocking Technique
zero-feedback discrete output stage
board dimensions : 107 x 100 mm
microcontroller operated
*As many of us already have the AD1865, the dac is available in a version where you can use your own IC!
The concept behind RD-3 was the realisation of a non-oversampling pure R2R dac with a true reclocking stage, while allowing multiple input frequencies/bit depths. To achieve that programable logic, analog filter loop and a tunable multi-clock synthetiser were used. The maximum jitter range of the synthetiser is well below the audible limit in non-oversampling systems. See image for the conceptual schematic of the reclocking stage.
The RD-3 board physical layout is presented on the diagram on the left. You can connect four leds as shown to indicate lock for the following usual frequencies : 44,1 khz - 48 khz - 96 khz. The fourth led will indicate when is lock in all other cases. No led is active without input signal. On the pin 6 you can install the switch to toggle between inputs : coaxial (default at startup) and optical. To power the dac a transformer with 9v/0.5A and 2x12v/0.3A ac output is needed.
Extensive LC power conditioning combined with active shunt regulation delivers clean supplies to digital and analog stages. Conceptual schematic of the RD-3 output stage is shown, a fully discrete implementation (no op-amps). In respect with phase accuracy very gentle filtering is applied to the signal, and no global feedback is present. The output buffer runs in single-ended class A for optimal musical performance.