Allo's excellent DAC BOSS comes back in a V1.2 release featuring high-quality components, USB Type-C power, and revised and revised design for increased audio performance.

An effective converter

The Boss DAC is a HAT format converter for Raspberry Pi based on a PCM5122 chip capable of decoding signals up to 32bit 384kHz. Its technologies are reminiscent of those of a Allo Kali Reclocker, combined in a compact and powerful 32bit DAC.

New in this version V1.2

Allo offers in the new version of its converter Allo DAC significant improvements. Thus, the clocks have been changed to last generation ultra-low phase NDK oscillators for a greatly reduced jitter.

The module now also offers a USB Type C connector to power it independently in 5V 3A. This of course remains optional and the Boss DAC can still be powered via the Raspberry Pi.

The design has also been revised to propose a more successful and optimized scheme. Finally, note the presence of new quality analog capacitors on the analog section of the module.

High-end digital processing in I2S format

Clocks generated by the Raspberry Pi CPU are not able to provide an accurate 44.1kHz frequency, which can cause problems with audio files sampled from 44.1kHz to 384kHz and resulting in a jitter that is far too high.

The Boss DAC generates its own Masterclock clock and recovers the entire DATA digital signal, ensuring very low noise drift. To do this, simply switch to I2S master mode on your dedicated software player, so that the Raspberry Pi no longer sends clock but only the data to the DAC.

The analog stage is designed to offer the least amount of passive components and uses film rather than ceramic filter capacitors for lower distortion.

LDO triple regulator with very low drift

The DAC Boss offers a unique design. It does in effect a separation of voltages on 3 channels via the use of 3 filters by shielded self and capacitors.

• A channel for the digital floor
• A second for the analog stereo stage
• A third for clocks.

The filtered signal is then recovered and filtered again by regulators (LDO) to obtain an ever lower noise. Note that Allo chooses to integrate among the best LDO regulators (Linear LT3042) market as well as high-end NDK clocks, similar to the recognized Crystek.

Finally, Allo also incorporates a super double capacitor acting as a current reservoir, avoiding the effects of pumping during high dynamic demands of the audio message.

All in all, the Allo Boss DAC, which is more V1.2 version is probably one of the best implementation of the DAC PCM5122 available on the market, correcting the problems of native clock Raspberry Pi and THD electrical pollution.