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Allo Boss2 Review (Stereo Streamer)

Eetu

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#21
Not sure if the PSU itself is great value. According to Allo "even a cheap PSU will degrade the THD by 1 to 2db".
 
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amirm

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Thread Starter #23
Thanks @amirm, great review as always. I understand you measured the Boss2 with the Nirvana power supply. Would you be so kind and measure it again with a “regular” power supply? Just want to see those graphs unchanged :). Thank you!
Sure. I grabbed one of the high-power generic switching supplies Allo had given me in the past. At first it generated a lot of power supply noise but then discovered a ground terminal underneath Boss2. Once I used that to ground it to my Audio Precision, all the noise went away. Seems like by default the device is floating. Likely this would have improved the performance with the fancy supply as well (doesn't impact distortions though):

Allo Boss2 Streamer generic power supply Measurements.png


So I don't think you need the fancier power supply other than it helping with ground loops.
 

notabenem

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#24
Can this device also be used as an otg-usb DAC only, i.e. hooking it to my PC through USB instead of a Motu M4 (which is difficult to get these days)?
Based on the images it also has a 3.5mm headphone jack. Measuring that too would be nice.
 
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Vict0r

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#25
I like the funky enclosure, and good for Allo that this measures as well as it does, but I have no idea how or why I'd use a device like this. :D Don't you need a proper screen? How would you navigate Roon using just the Allo remote? Wouldn't it make more sense to use a tablet with an otg-usb dac attached?
 
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amirm

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Thread Starter #26
I like the funky enclosure, and good for Allo that this measures as well as it does, but I have no idea how or why I'd use a device like this. :D Don't you need a proper screen?
You do not. These streamers are used in "push mode." In a player like Roon, I use my own player and just "beam" the audio to this streamer next to the audio system. Your interface is in side Roon. The device basically makes your DAC work on Ethernet/Wifi cable instead of USB.
 

johan

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#27
As usually , I would like to say ,thx you Amir , for your time and effort . The audio world has changed and Amir is one (main) of the driving forces .

Now getting back at Boss2. For a long time , earthing was a big part of audio . With XLR outputs it becomes less important (but still relevant). With the correct earth , RF has a path to escape . Some of you will argue that its not important , but in all my test data , I see a clear improvement with earth. Therefore all our power supply , DACs etc have a way (and some multiple) to earth using various C+R values .

Earthing is not standard . What works on one system might not work the same , on a different location . Again , this is why we have a DC earth (Nirvana SMPS) but also an earth lug on both Nirvana and Boss2 (for direct connection )

Boss2 has also multiple ways to power it, you can use one DC power (both Boss2 and RPI4) or use 2x PSU one for Boss2 and one for RPI4 (with the GND shared of course). I will not comment on "how it will sound" but from what I remember we got slightly better THD+N

About our company . We are a canadian company that has a R&D center in Bangalore India and a smaller one in EU . We work as a team and we are proud of our work .
 
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johan

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#31
You can see the clocks and buffers with RF shield and every voltage rail has a dedicated LDO. In addition , we used many electrolytic caps to make sure that enough electrons can be supplied on any load change. Please note the supercaps on the corner (battery really ) that supply the main analog rail with plenty of power .
The black wire is used when deciding to move from one psu to two .
 

johan

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#35
I would like to explain how a streamer works . RPIs hardware is a small computer that has an open sourced OS. Many audio players , like Moode , PCP . Volumio etc build on that OS using open source software .

From your tablet/phone , you can stream direct to our Boss2 using airplay , upnp/dnla , spotify plug in , roon and more coming . You can swtich at any time betwen players by flashing the SD card with the new image.
 

johan

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#36
USB type C can do up to 3A, otherwise it wouldn't be used as the power input of the Pi 4.
You have the choice of powering through both inputs . However RPI input does not have the same filtering arrangements "common mode chockes , PI filters" as main DC in the back.
 

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