Allo Boss DAC: The Raspberry Pi (RPI) has one major problem with audio—the clocks coming from CPU can only output one frequency clock perfect (very close), resulting in major problems with audio files sampled at 44Khz (and multiple). Too much jitter on i2s clocks. So they invented the Kali but there is a second way.
Enter the master mode for i2s. Instead of the RPI giving the clock on the line, the DAC itself sends the clocks and RPI sends the data (file to be played). Since they used 2 clocks the problem above disappears. Theirs is not the first master DAC on the market, there are others… read on.
The Allo Boss DAC is unique, because of the way they have implemented the design. First they separate the power on 3 channels and filter it: one for the digital side, the second for analog and third for the clocks themselves. Then they take the filtered power and use a second filter (LDOs) to further quiet the noise. Note that they use some of the best LDOs on the market (LT3042 from Linear). In addition, they use Japanese oscillators from NDK for a very low jitter clock – almost as good as famous Crystek.
Finally, on the analog stage they are using a film capacitor (not ceramic) for a quiet DC to feed the TI IC (ceramic exhibit some piezo distortion, not what you want in analog stage). Not happy with this, they have added a supercapacitor for an extra kick when analog stage is asking (like deep bass).
What they have achieved, in Allo’s opinion, is the best analog implementation of the PCM5122 on the market, while at same time correcting the clock problem from RPI.
For more information on Allo kindly use this—LINK