Fully Discrete R-2R Resistor Ladders DAC, Built In 4 Groups of DA-8 V2 Modules, Built In FPGA Processor to Reject Jitter , DSD , DXD 32bit / 384K Support From USB / HDMI, Built with OCC and Hi-end parts
Price: 854.20 EUR ( 694.47 EUR Net Price)
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DAC R2R-1 #


Audio-Gd R2R11



Fully Dedicated Discrete R-2R resistor ladders technology applied
OS/NOS modes selection on front plate
USB / HDMI inputs include
Built in 4 groups DA-8 R-2R modules
Built in FPGA processor , reject the jitter
DSD , DXD support from USB / HDMI
32bit / 384K Asynchronous Transfer Amanero Combo 384
Built in OCC , and Hi-End parts



Some customers may consider the DAC's sound flavor depend on which DA chips or parts built in.
But this is not true. We can adjust the sound flavor to which is we like . In NFB-7.77, it had built in the ES9038 Pro chips but its sound just similar to R2R 7 , had not the Sigma Delta sound . The discrete R-2R design had the better detail and transparency than the classis R-2R chips. We are consider in this middle/ low range price, users may like the sound more smooth and analog , so we increase the even harmonic and odd harmonic, spend a lot time to adjust and test the harmonic and frequency band , listen the sound quality and flavor for finally confirm the parameter. A lot people may know the even harmonic , just like the tube design, proper even harmonic especial 2x harmonic made the sound tube like and smooth . But a lot people even some designers don't know the proper odd harmonic especial 3x harmonic can make the sound lively. If you like to looking for the good specs, R2R 1 may not as good as the same price range ESS9028 Sigma Delta design, but its sound is analog and smooth. The balance combo always had the sound more neutral than single ended combo. If you like neutral much , you can consider R2R 1 + NFB1AMP . On the other hand if you want the sound slight warmer for your listen taste or match with the bright sound headphones , R2R 2 + C 2 is the choice.

Pros and cons of R-2R DAC : Advantages: 1.R-2R will not convert the clock signal into the output signal. 2. R-2R is not sensitive to jitter while Delta-Sigma DA is much more sensitive to jitter. 3. The output signal is much more precise compared to Delta-Sigma DA . Weaknesses: 1.THD today is extremely good with Sigma Delta chips; R2R ladders are good too but not as good. 2. Glitches and accuracy of the ladder resistors are very difficult to avoid and require complex technology to resolve it.

R-2R basic design in the market: The R-2R DAC is very popular nowadays and available from DIY kits and completely up to of the shelf high-end products. In the low range DIY market, the R-2R design is often based on old technology designed a long time ago by MSB and only includes basic R2R ladder design and do not include the wonderful correction design of the original MSB technology. This design uses data shift registers logic chips in series mode to convert the data to an analog signal. The structural R2R technology issues cannot be avoided, and performance is solely depending on the accuracy of the ladder resistors.

In the High-End of the shelf (finished products) market, the R2R design is much more complex only to reach best performance. A basic R2R ladder is simply not sufficient enough to achieve good performance and sound quality! Some manufacturers are using shift registers design. A less complex and less performing design based on traditional logic chips working in serial mode to correct the ladder. A far better design switches resistors in parallel mode. An ultra-fast FPGA controls and corrects the R2R ladder. The parallel design mode controls every bit respectively and therefore achieve unprecedented performance. (In parallel mode only 1 clock cycle is needed to output all data; serial design mode needs at minimum 8 up to 24 clock cycles) The parallel design is much more complicated. Once designed properly it can correct every bit of the ladder. Photo below shows a design with such FPGA, can correct the unavoidable imperfections of the R2R ladder caused by tolerance of resistors, glitches to achieve best performance.


Audio-Gd R2R-1


Importunacy of the FPGA in the R2R 1: FPGA stands for Programmable Array Logic. Nowadays the FPGA is applied in a lot high end grade DACs; like the popular ROCKNA WAVEDREAM DAC. The internal hardware design is fully controlled by complex software. A huge advantage is the fact the software in the FPGA can easily be upgraded offering new features or improve the performance. Such design is much flexible and future proof!

FPGA tasks in the R2R 1 The FPGA in the R2R 1 is responsible for: 1. High performance SPDIF interface, replacing traditional less good performing SPDIF interface chips like DIR9001, WM8805 or AK411X,etc. 2. Full re-clocking process with FIFO design applicable on all inputs. This way the output data keeps fully synchronized with the clock signal to reject any jitter. 3. Built in 2X, 4X and 8X oversampling and digital filters and on top of this 4 different true NOS (only analog 6dB filtering) modes. To completely configure it to your liking!

Fully discrete real balanced output stages The signal last stage is the analog output stages, they can much effect the whole DAC sound quality. After d/a conversion by the R2R D/A modules the analogue signal is transported by fully discrete matched-transistor output stages. DC-coupled design with first class through-hole components. No SMD components are applied. The high speed special ACSS output stages are non-feedback and current driven design. Special because almost all other designs need to convert the signal multiple times from and to current or voltage, resulting in less detail and less good staging. The output buffers are single ended FET. Two stages in parallel to reach very low output impedance. All output stages are in pure class A design without any (negative) feedback to achieve purest and a real live sound reproduction. The 4 OPA opamp’s are functioning as DC servo, this way no coupling-capacitors are needed and DC output is automatically biased! Resulting in a perfectly neutral sound. There are no relays or other switches in the signal path after DA modules to perform the best and purest sound quality.

https://pliki.ip-sa.pl/audio/attach/R2R-1-eng/R2R12.jpg



Specification:#

S/N Ratio: >110DB
 

Output impedance: <10 ohm (RCA/ XLR): Output Level:
2.5V (RCA)
5V (XLR)
2MA+2MA (ACSS)
Frequency Response: 20Hz - 20KHz (< - 0.5DB)
THD: <0.003% (20Hz-20KHz, Non-Weight)
Input Sensitivity:
0.5 Vp-p ( 75 Ohms, Coaxial )
19 dBm (Optical)
USB1.0 - USB3.0
Support Operate Systems (USB): Windows, OSX, Linux, ISO

Support Sampling:
USB mode and HDMI: 44.1kHz - 384kHz /32Bit
USB mode and HDMI: DSD64-256
Coaxial mode: 44.1kHz - 192kHz /24Bit
Optical mode: 44.1kHz - 96kHz /24Bit
Power Requirement
Version 1: 100-120V AC 50/60 Hz
Version 2: 220-240V AC 50/60 Hz

Power Consumption:
19W

Package Weight: Approximately 5KG


Dimensions: W240 X L360 X H80 (MM, Fully aluminium)
Accessories: AC power cord X1 USB cable X1