Skip to content
Delivery time upon request.
(All devices are handmade to customer order)
R-8HE MK3
True symmetrical fully discrete R2R ladder DAC mwith built-in regenerative power supply.
New features and improvements
It's been 3 years since the R-8 was launched in 2018. Thanks to the R-8's fully programmable circuitry, we have continuously updated the firmware to improve the owner's experience.
The R-8HE MK3 was developed and tested in the first months of 2021, followed by more than half a year of continuous listening and software and hardware fine-tuning.
The R-8HE MK3 uses the latest discrete, servo-stabilized power supplies, whose performance is comparable to that of batteries after more than a year of calibration and optimization of every part of the circuit.
The DA sections use these new discrete servo-stabilized power supplies, the analog circuits are still powered by pure Class A power supplies to achieve the best sound, as determined by listening tests.
Production and sales weren't planned until we were completely satisfied with the realistic sound. The improvement over the previous generation is quite obvious.
1. Completely discrete components are used in a truly balanced power transfer design. Four sets of fully discrete and independent DSD hardware decoders.
Eight sets of fully discrete R-2R DA modules to form a symmetrical two-channel push-pull decoder. The DA circuits are powered by the latest discrete, servo-stabilized power supply. The noise level is comparable to that of a battery, but without the dry and thin sound characteristics, allowing the product's operating temperature to be significantly lower than that of the previous model. The analog circuits are still powered by a pure, regulated Class-A power supply for optimal sound results (new upgrade).
2. Through extensive listening and study of the sound of a turntable, we have succeeded in integrating the sound characteristics of analog vinyl into this product, which is optionally available via the front panel. (New feature)
3. Both the USB and HDMI inputs are equipped with isolators and two sets of linear power supplies that supply power to the USB and HDMI modules separately before the isolators to avoid interference from signal sources.
a, USB uses a two-way transmission isolator, which not only transmits the IIS signals to the FPGA processor, but also receives the synchronous clock signal sent by the FPGA processor.
The USB interface itself is no longer equipped with clocks. Synchronous clocking is used to increase signal transmission accuracy and raise sound quality to an excellent level. The sound quality is now actually better than the previous generation R-8 2020, which is powered by the DI-20 (although not quite as good as the DI-20HE).
b, the HDMI module is now equipped with an independent isolator to improve the sound quality of the HDMI input.
4. Function to display the sampling rate of the input signal. (New feature)
5. The digital circuits of the entire DAC consist of an FPGA and five CPLDs (both programmable components), which allow separation of the different functional circuits and prevent interference. The FPGA operates in parallel data processing mode.
The IIS signal is a serial data transmission.Each data bit requires one clock cycle. A frame of left and right channel data requires 64 clock cycles, so stability over 64 clock cycles is required.
Parallel mode requires only one clock to transmit and process the 32-bit data of the left and right channels, which greatly improves the processing speed and is less affected by the stability of the clock.
The IIS input data (USB and HDMI IIS) is reorganized into two parallel 32-bit data sets as soon as it is input. After the SPDIF signal is demodulated, it is also forwarded to the next processing stage via two parallel 24-bit data sets.
DSD data is also reorganized into two groups using 64-bit parallel processing as it is input.
According to listening comparisons, the parallel processing mode can make the sound clearer and more neutral, with better dynamics and a more analog taste.
6. Two world-class Accusilicon TCXOs operating at 90 and 98 MHz ensure synchronization of the entire device and are used for playback at all data rates without PLL upscaling. The new architecture's clock management design ensures a more stable clock, resulting in greater transparency and more detail.
7. DSD uses the built-in asynchronous clock to improve timing, which significantly increases the clarity and dynamics of playback.
8. SPDIF supports DOP playback.
9. All digital mode settings can be changed live on the front panel.
10. There is a firmware upgrade port on the back of the device (no need to open the cover to update the firmware).
Fully analog renewable power supply
A renewable power supply is like a private generator built into the machine. It can filter out power line noise to a large extent, supplying audio components with ultra-pure power, and delivering rich and impressive bass and a high-quality analog signal to the audio system and end users.
In the implementation of the regenerative power supply, the 120V/220V AC is converted to DC via the regenerative input transformer, which is then delivered to the regenerative waveform generator and driver via a parallel stabilized Class A power supply.
A set of symmetrical regenerative waveform generators produces an extremely low-distortion 50 Hz sine wave. Following a symmetrical amplification stage and a powerful driver stage, three regenerative output transformers output a pure voltage that is stable in both amplitude and frequency.
Two sets of parallel-regulated Class-A power supplies independently power the analog output stages of the left and right channels, as well as the digital audio sections with their various processing functions. Both the regenerative waveform generator and the driver are powered by a stabilized Class-A power supply, ensuring their operation is unaffected by mains fluctuations and interference.
The Class A shunt regulator has a very high input impedance to block interference and prevent noise on the power line from entering the audio circuit and degrading sound quality; it also eliminates crosstalk generated by the left and right signals from the power supply, improving isolation.The low output impedance has excellent linearity and speed, which also allows for an excellent design for a regulated power supply. Audio-gd's
Arguments for the design of the renewable power supply:
1. Through the internal design analysis and actual test comparison of AP SYS-2722, the distortion of the pure analog regenerative sine generator is much lower than that of digital synthesis generators.
2, The digital drive stage can have higher power conversion efficiency, but the fully analog drive stage has a more analog flavor.
3. The regenerated waveform frequency of 400 Hz has higher power conversion efficiency. However, the regenerated waveform frequency of 50 Hz is farther from the sensitive range of human hearing than 400 Hz, and the sound quality is therefore softer and more natural at 50 Hz.
The advantages of the R-2R DAC:
- R-2R does not convert the clock signal into the output signal.
- R-2R is insensitive to jitter, while Delta-Sigma is very sensitive.
- The output signal level of R-2R is more accurate than Delta-Sigma.
