mdXS - ALLO MiniBoss Review

Since our last listening sessions and findings in 2015 a lot has been developed on the I2S DAC board market. Several fun projects
retrofitting vintage amplifiers with volumio based streamers – kind of bulky projects though – have drawn our attention to the now available Raspberry Zero W and matching I2S DACs. Especially the antenna mod (who wants a wifi inside a metal case) and the new ALLO MiniBoss seem to be
the right material for such projects.

One important detail for us in 2015 was proper power supply – or more precisely, regulated linear power supplies to the various sections of the circuit to create a best sounding streamer (within humble means) possible. Early on we modified available boards, locked into regulators and PSUs to hear what such cheap material could sound like (summary here). Key findings – a PI + DAC board could match Xk$ units at ease.

How does all of that looks like in 2018, what’s new?

ALLO MiniBoss for Raspberry PI Zero Review

Just to calify we are using a standardised base for comparing DAC boards in our listening sessions. We have identical regulator boards on Raspberry PI 1s, controlled over wifi with the latest Volumio playing various audio files directly from the micro SD. This way the DAC boards have their own clean power supply and can show their full potential.
Next to the

  • ALLO MiniBoss we brought in two other PCM5122 based DAC boards
  • IQaudIO Pi-DAC+ (our faforit in 2015, “PLL clocked”)
  • HifiBerry DAC+ Pro (an early introduction of dual domain master clocks on board)
    and referenced the setting once in a while to our best streamer of 2015 + a Naim DAC. If of any interest - all was fed into an active Naim bricks/Linn Isobarik system – something quite unforgiving if something is wrong.

Well, we have to admit we are impressed.
The ALLO MiniBoss produces a great sound stage where the music is more present in the room than something projected from speakers. This might be due to its ease and volume (not boost) in the low range. It has a colorful mid range rendering e.g. violins quite beautifully. A high soprano challenging literature’s limits or snares can be a little bit rough but the overall and at first hand enjoyable musicality definitely states: something quite new has been introduced here which the other two boards don’t show. Especially the IQaudIO as is doesn’t impress anymore in this trio.
Comparing it to our 2015 built (heavily modded IQaudIO, now with two expensive SuperTeddyRegs for PCMs AVDD and DVDD) we are reminded that towards to upper limit of improvements it becomes again a question of eliminating whatever is not music. Here the IQaudIO is back in the reign with a less obvious but subtle preciseness you never get tired of.
This shows us that the importance of a clean (designated) and powerful power supply – which we had to built several of them and with great effort around our DAC boards in 2015 – does matter. ALLO has recognised this and has implemented it on their current DACs. Their work (with the reclocker detour) has also made on board master clocks a standard.

First surprise – the board did not arrive as shown in the shop. The metal shield for the clocks was missing. For whatever reason – consistency would have be better.
The multi-layer pcb would make modifications more difficult but we think the board and its possible implementations are not meant for that anyway. Compared to the two other boards all onboard LDOs also seem to draw power from the GPIOs 5V pin only (maybe a Zero spec??).
The RCA connector do not have any screw holes (like the IQaudIO DAC) to support mounting and there are no soldering points for output too – understandable, the board is packed.
Other that that everything is just fine and the size to quality ratio is impressive:

Our first implementation will be inside a beautiful Linn Classik which we are looking forward to!

PS shopping experience:
Thanks to the Volunio Store to spare one from any unfortunate overseas import experiences and for prompt shipping.

Thx you , we appreciate the kind words. :slight_smile: