Skip to content
Delivery time approx. 2 weeks.
Highlights
-
8 fully discrete R-2R DA converters (2 pieces DA-7 boards) working in balanced mode.
-
4 fully discrete native DSD decoders operate in symmetric mode.
-
32bit / PCM384K /DSD512 asynchronous transmission via the Amanero 384 usb input.
-
All inputs with galvanic isolator
-
Fully discrete structure of the current signal transmission without OPA in the signal path.
R-1 NOS DAC - pure, natural sound
Some people love the sound of pure NOS mode, so we designed the R-1 NOS to optimize pure NOS mode and provide pure musical sound.
The NOS design does not need the main clock signal to work, which is the advantage of the NOS design to avoid the effect of the main clock jitter.
In the R-1 NOS digital processor, we apply Zero Delay technology, which guarantees exact synchronization of data and clock to reduce jitter.
In the R-1 NOS design, we apply the galvanic isolator in front of the DA parts and analog parts, isolating the all digital inputs and the digital processor, which provide the better clean sound quality.
8 groups of built-in 24bit R-2R decoders and 4 native DSD decoders working in symmetric mode, we use the DA 7 modules which are an obvious upgrade over the last generation R-1.
By using the latest discrete servo-stabilized power supply to power the digital circuitry, the noise level is comparable to that of a battery but without its dry and thin sonic characteristics, and thus the product's operating temperature is significantly lower than the previous model. The analogue circuitry is still powered by a pure Class A regulated power supply to achieve the best sound results.
Tube-like sound
The basic version of NOS has a tube-like sound or vinyl feel. It may have to do with distortion similar to this, usually between 0.01% and 0.1%. Some expensive US-made DACs have even worse specs, but many people find they sound nice.
The distortion of the R-1 NOS is comparable to that of a vacuum amplifier or turntable and to that of the expensive US-made DAC mentioned. But the noise level is better than 120DB, much higher than that of vacuum amplifier or turntable.
Some things you should know about NOS design before you buy it
"NOS" stands for "Non Oversampling". When using a NOS design, the specifications are ordinary as the limited bit depth of the signal affects THD and S/N.
Despite the fact that quantization noise affects signal noise, the R-1 NOS still achieves very low noise figures, much better than most tube amps and turntables.
To get better specs on paper, many designs use a fairly complex LC analog filter after D/A conversion. But the LC filter typically does not have a flat frequency response, and the large phase shift it introduces also severely degrades the sound quality.
In the 1980s, oversampling and FIR filters were invented, which allowed an improvement in sound quality compared to using an LC filter. Good results were achieved on paper, so this technology has been widely used ever since.
However, some people still liked the sound of the NOS design better and felt that without the extra processing it could better preserve the original character of the sound, like in the real world, trusting their ears rather than the specs .
Accuracy of conductor resistances (tolerance)
Many people believe that the tolerance of the resistors in the ladder is the most important thing to get the best performance. Nowadays, a resolution of 24 bits is standard. What tolerance is required to achieve 24-bit resolution?
If we consider 16 bits, the tolerance of 1/66536, 0.1% (1/1000) is far from enough, even a tolerance of 0.01% (1/10000), the best tolerance that there are in the world today still can't handle 16 bits correctly; we don't even expect 24 bits here!
The tolerance of resistance will never solve the imperfections of a conductor. This would require resistors with a tolerance of 0.00001% and a resolution of 24 bits. This is only theoretically possible as the discrete switching logic chips already have too high an internal impedance and would destroy the impossible tolerance of a resistor.
The solution is to correct the ladder and not rely on the tolerance of the resistors. It is a combination of both: very tight tolerance resistors controlled by correction technology and a very fast FPGA/CPLD used in our design.
The importance of the FPGA/CPLD
FPGA/CPLD stands for Programmable Array Logic.
Nowadays, the FPGA/CPLD is used in many high-end DACs, such as B the popular ROCKNA WAVEDREAM DAC.
We have been using FPGA/CPLD in our DAC products since 2008. R-1 NOS has built in 6 CPLD programmable chipsets to separate the different configured circuits and avoid interruptions.
The internal hardware design is fully controlled by complex software. A major benefit is the fact that the software in the FPGA/CPLD can be easily upgraded to offer new features or improve performance. Such a design is very flexible and future-proof!
