Thanhvo31
Well-Known Member
Một số transport HAT từ bình dân tới cao cấp.
all use WM8804, trừ DiGiOne là WM8805.
all use WM8804, trừ DiGiOne là WM8805.
- JustBoom Digi HAT for the Raspberry Pi (https://www.justboom.co/product/justboom-digi-hat/)- $39- COAX + OPTO
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Technical Information
- WM8804GEDS S/PDIF Transceiver with 24bit/192khz and has an integrated low jitter PLL (50ps RMS)
- DA101JC high bandwidth digital output transformer for galvanic isolation on electrical (coaxial/RCA) output
- Integrated EEPROM for automatic Raspberry Pi devicetree driver configuration and fully HAT compatible
- Digital signal output over S/PDIF with either optical (TOSLINK) or coaxial (RCA) connectors
- We recommend that if you are using the coaxial/RCA output that you connect the cable shield to the ground on the DAC / amplifier you are using and make sure that the the DAC / Amplifier is using a power supply with the ground pin connected. This will help to reduce noise
- Bit perfect digital audio transmission
- Optional Vishay TSOP4838 IR receiver included in package (solder yourself if required)
- While the hardware is able to output DTS/Dolby Digital, the Raspberry Pi software is not currently able to support this. Let us know if you want to implement this and we will do our best to help
- IqAudio Pi-Digi+ (http://iqaudio.co.uk/audio/48-pi-digi.html) - $39 /galvanic isolation transformer COAX + OPTO
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The Pi-Digi+ plugs directly on the Raspberry Pi A+/B+/2/3, there’s no need to solder or modify your Raspberry Pi and you can be enjoying Full HD optical or electrical digital audio in minutes.
We've used the WM8804, added IQaudIO build quality, electrical isolation as standard and re-exposed the Pi's 40way header so you can add other "bells and whistles".
A fully HAT compliant Raspberry Pi expansion board with EEPROM support, the Pi-Digi+ delivers Full HD audio from your Raspberry Pi with driver support already in the official Raspbian Linux distribution.
- Raspberry Pi HAT (A+/B+/2/3) compliant accessory
- Full-HD audio – up to 24-bit/192kHz playback
- Built in Electrical isolation
- Wolfson WM8804
- Advanced ESD protection
- Uses the digital I2S audio signals to reduce CPU load over USB audio solutions
- Raspberry Pi powered, no external power requirements
- Industry standard audio quality RCA and optical connectors
- Fully built and tested Raspberry Pi accessory
- Designed and manufactured in the UK
- HIFIBERRY DIGI+ ( ) $49.90 galvanic isolation transformer + clock riêng
[*]The digital interface for the audio enthusiast. Features a low-noise power regulator and dual-domain clock generator.
FULL SPECS
The HiFiBerry Digi+ family contains high-quality S/PDIF output boards with the following characteristics:
- Dedicated S/PDIF interface chip supports up to 192kHz/24bit resolution
- Optical (Toslink) and electrical outputs
- Bit-perfect output—audio data stream will not be modified in any way
- Connects directly to the Raspberry Pi—no additional cables needed
- Directly powered from the Raspberry Pi—no additional power supply
- Optional: high-bandwidth output transformer provides full galvanic isolation of the electrical output (not in the standard version)
- Integrated EEPROM for automatic configuration
- Comes with all components required to mount it (we include fitting spacers to fix the board onto the Raspberry Pi)
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- Pi2Media 502DAC - Pro Audio Shield (http://www.pi2design.com/store/p15/502DAC_-_Pro_Audio_Shield.html ) - US$89.00
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Features
- 24-Bit DAC – Highly regarded -112db THD PCM5122 running in Master Mode converts the I2S Stream to Analog at 24-Bit up to 192Khz Frame Rate
- DIGITAL AUDIO – Industry standard WM8804 converts the I2S stream to Pro-Audio Standard AES/SPDIF formatted data at 24-Bit up to 192Khz Frame Rate
- ULTRA-LOW NOISE CLOCKS – Two NDK NZ2520SD Oscillators feed the PCM5122 and WM8804 to insure the lowest possible Jitter and Phase Noise.
- ANALOG OUT – 2Vrms Stereo Line Out is available via Dual RCA Gold Plated Jacks
- BALANCED OUT – Isolated Balanced AES/EBU Pro-Audio is via ¼” Connector (XLR Adapter is available)
- COAX OUT - A BNC COAX connector provides single ended, isolated S/PDIF with selectable Output levels for
both Pro and Consumer equipment
- OPTICAL OUT – Via TX179 TOSLINK Transmitter
- HIGH-PSRR LDO – A Low-Noise Linear Tech LT3042 delivers 3.3V to all sections and provides 88db+ PSRR
over the entire audio band
- EXTERNAL 5V – This option allows the 502DAC to be powered from an external low noise supply if desired.
- 24-Bit DAC – Highly regarded -112db THD PCM5122 running in Master Mode converts the I2S Stream to Analog at 24-Bit up to 192Khz Frame Rate
- Allo DigiOne (https://www.allo.com/sparky/digione.html) - $99
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[*]
[*]RCA and BNC outputs (gold plated) only (absolutely no optical, it has by definition 4ns of jitter). No AES either its not a good medium for digital signals.
Noise level under 100uV ,we hope for 50uV, at the output.
Jitter target at BNC/RCA under 3ps on both outputs (we hope for 1ps).
That means no transformer for galvanic isolation , what we do is isolate the board at the input (after the wm8805) and then reclock with NDK Oscillators feed with own LDOs+ filters. (with meta-stability solved)
In total we use 10 LDOs on the board, 12 low pass filters, multiple buffers (with 0.07ps added jitter), digital isolator, common mode choke , isolated DC/DC convertor with filter on input and output.
We have a target price of 119 Eur...but its not set in stone.
Target release date April 30 (Sunday)...we will do our best but don't take it as a guarantee.
Basically what we think, its that DigiOne will be the best digital transporter on the market at ANY price (yes including those 5kEUR/USD transporters)
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