GOLDENWAVE said:
From the first decoder to the later GD-01\GD-X, etc., the D/A chip of AKM is used, and it has been more than 7 years. It has been 2 years since I got the AK4497 in 2016. During this period, there were various trials, various delays, and various overturns. I deeply feel that it is really not easy to make a DAC with AK4497. We have been developing and testing one. The matching digital processing module, which is the current solution, completes the design of this series. The three machines are all extended from our newly developed digital processing module. This is not a simple digital processing module. It supports: SPDIF input and SPDIF output processing, which can be used as a digital interface; support USB input, SPDIF& I2S output can be used as a USB interface; a higher-quality clock reference can be connected through the SYNC IN clock interface; a complex and reasonable PLL clock system provides a clock signal for the entire digital processing module; hardware FIFO is used for better data depth deal with. . . . . and many more.
All input interfaces of Sapphire III/GDX support DSD, and SPDIF input supports up to DSD128 and PCM384K. It can be used as a preamp output to connect to active speakers; it can also be used as a DAC output to connect to a preamp/amp; the USB part still uses the mature and stable USB interface of XMOS XU208, and the digital processing module provides it with extremely low noise and extreme High-precision clock signal, and the XMOS I2S signal is reformed and processed to maximize the performance of xu-208.
Sapphire 3 & GDX all have pre-level output mode, which outputs variable-level audio signals. We have also made a big update to the volume adjustment. It is no longer in the form of relay switching resistance, but uses a higher-level solution. The channel uses a piece of R-2R ladder dac, and uses its internal resistor network to adjust the volume. This is a complete upgrade, with better linearity and user experience.
The decoding motherboard of Sapphire III and GDX is the same, the difference is that Sapphire III will optimize the pre-driver, and the effect will be better when connected to active speakers, while GDX has an additional headphone amplifier module and the analog circuit The power support will be better, after all, the consumption of the four-way headphone amplifier is less.
On the basis of Sapphire III, GDX adds a completely independent four-way fully balanced Class A headphone amplifier. GOLDENWAVE''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s newly optimized design separates pure class A fully balanced headphone amplifier driver module OB-2, four identical independent amplifier units, optimized design of the current and gain distribution of the amplifier at all levels, and the output voltage swing is close to the power supply voltage. With extremely low output impedance and extremely high drive capability and dynamic range, easily obtain 3000mW/32Ω; 450mW/300Ω output power(0.08% @1k, balanced output).
Technical index(The final shipment will be slightly optimized, subject to the announcement of the final official website manual):
1. USB supports DSD64, 128, 256; PCM 16-32bit, 32-384KHZ
2. Coaxial, optical, AES input: DoP64-128, PCM16-24Bit, 44.1-384KHZ
3. IIS input supports DSD64-512
4. Signal-to-noise ratio: -126dB
5. THD+N: 0.0007% @1kHz
6. Frequency response: 20-30KHz, +/-0.1dB @1kHz
7. Left and right channel separation: -110dB @1kHz
8. Balanced output level: 4.2Vrms @0dBFS
9. Headphone amplifier output power(0.08% @1kHz, balanced output)
3000mW@32Ω, 1700mW@64Ω, 800mW@150Ω, 450mW@300Ω, 200mW@600Ω
10. Eight kinds of digital filters, DSD provides Wide BW/Narrow BW ; PCM provides Short Delay Sharp / Short Delay Slow / Sharp / Slow / Low-dispersion Short Delay Filter/ Super Slow
11. Power consumption: <50W
12. Size: Width 278*Depth 245*Height 58 mm, excluding raised parts
13. Net weight: 5kg
GD-X adopts AK4495 decoding chip, XMOS U8 USB chip, self-developed clock processing system, decoding amp front stage is fully balanced structure, amp front stage adopts pure class A design, supports DSD, digital control, LCD display