One dedicated S/PDIF interface supports up to 192kHz/24bit resolution via Optical (Toslink) output.
Using the I2S expansion port on the C2 / C1+ / C4, we save a USB port and allow the user to select their audio playback system of choice, such as Volumio, Debian(DietPi) for HiFi audio playback.
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Functional introduction:
- Volume control via I2C interface is great feature to keep the great audio quality with various audio output volume.
- The output ports include gold-plated stereo RCA terminals
- An ultra-low noise dropout regulator is populated for the power supply, significantly reducing power supply noise and greatly increasing the signal to noise ratio.
- The I2S interface allows for direct decoding of the digital input to analog output using master clock synchronization.
- The PCB surface is comprised of gold-plating on top of 2 oz. of copper, ensuring signal continuity and reducing signal reflection and refraction.
- Balanced(differential signal) audio output soldering pads are available.
- The dedicated S/PDIF interface is newly added which supports up to 192kHz/24bit resolution via new Optical (Toslink) output.
* ODROID-C1+ supports up to 384Khz while the ODROID-C2 supports up to 192Khz.
* This HiFi Shield 2 is partially functional on Android. The output format is fixed at 44.1Khz/16bit stereo. There is no Analog volume control capability either due to limited AOSP audio HAL implementation.
– Ubuntu/Linux setup guide : https://wiki.odroid.com/accessory/sound/hifi_shield
– Official Volumio OS support : https://volumio.org
– Official Runeaudio OS support : https://runeaudio.com
– PCB mechanical drawings (AutoCAD format) : Download HERE
– Schematics : Download HERE
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Package include
– HiFi Shield 2 Board
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BOARD DETAIL
The audio output is the other way as standard. Red : Left, White : Right
BLOCK DIAGRAM
ODROID-C2 / C1+ / C4 7PIN I2S PINMAP
The HiFi Shield 2 is a high-resolution Digital to Analog Converter(DAC). This is a special sound card for the C4, C2 and C1+, that is optimized for the best fidelity audio playback quality. It delivers a nicely balanced sound, solid, deep, wide and nicely layered.
We’ve analysed the the audio quality of the HiFi Shield 2 DAC output with the famous industry standard equipment, Audio Precision. The Audio Precision is a high performance audio analyser optimized for the digital audio product.
The analog output of the HiFi Shield 2 is connected to the equipment and measurement data shows on the host PC.
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Test conditions
Volumio 2.002 image runs on the Odroid-C2 with HiFi-Shield 2. 192KHz audio test files were used.
Audio Precision Input : Analog unbalanded 2ch, 600ohm
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Hardware volume/mixer settings
Analogue : -6.00 dB (amixer -c 1 sset Analogue 0)
Digital : -3.00 dB (amixer -c 1 sset Digital 201)
Deemphasis Filter : On (amixer -c 1 sset Deemphasis on)
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Software volume settings
Volumio UI volume : software volume 100 (maximum full scale)
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Set-up with ODROID-VU5
Set-up with ODROID-3.5inch Touchscreen Shield
The Signal to Noise Ratio (SNR)
The Noise Level in dBm
The Frequency Response and RMS output level in dBV
The Total Harmonic Distortion + Noise Ratio (THD+N)
The Frequency sweep THD+N Ratio
The FFT spectrum analyzer for 1Khz signal
This is a great idea if you want an audiophile set-up with ODROID-C2/C1+. Enjoy a variable output connecting directly into a power amp or active speakers.
