As a companion for the cd/dvdrom control kit as well as stand-alone, we are happy to introduce to you Rockna RD-2 D/A converter. Designed to meet actual audio standards, the RD-2 offers on a compact smd board a considerable number of audiophile flavours, beginning with the active parts mix (spdif receiver from Cirrus, jitter rejection from Analog Devices, dac from Burr-Brown) and continuing with the low jitter master clock and a zero-feedback, low impedance discrete output stage.
input frequencies : 32, 44.1, 48, 88.2, 96, 192 Khz
number of inputs : 2 (optical, coaxial)
bit depth : 16 to 24 bit
S/N ratio: 105 dB
THD : 0,04%
IMD : 0,05%
Low impedance output (30 ohms)
Bandwidth : 10 Hz - 20 Khz, +/- 0.5 dB
careful layout, very short signal path
ultralow jitter reference oscillator
dac (assembled) dimensions: 108x45x220 mm
The design philosophy of the RD-2 is concentrated on the following key-points : multiple input frequencies/bit depths and ultra accurate d/a conversion, fully discrete i/v conversion and output stage, jitter immunity regardless of the quality of the source. To achieve that a careful implementation of one of the best ic's available was realised into a very compact design.
The RD-2 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. On the left the schematic of the RD-2 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.