Why? On which parts/pieces does it improve what?
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The ground is supposed to be always at 0.
However , in every SBC , but especially in RPIs, the ground is full of noise due to CPU switching at hi frequencies and not being sufficiently bypassed (small capacitors on pins of ICs)
So this ground noise is leaking into any grounds shared…ie DAC. If you quiet the ground (isolator , isolates grounds) your DAC will be quieter thus improving the clocks and analog going out.
Ok thanks 
A sparky comparatively has less noise right ?
Hi, has anyone a CAD model of RPI3 + Allo Boss? I’m looking for a simplified CAD model in order to build my own case by 3d printing.
Is it possible to connect Boss to Raspberry 3 and to the original touchscreen at the same time and put them all together in the original enclosure to have a player like logitech squeezebox ?
I am a newbie. Try to start this small project.
Hi,
I just got the Boss DAC and hooked it up to a brand new RPI 3 with latest DietPi. However, I cannot get any sound out of it.
Drivers are loaded, card shows in alsamixer and aplay, LED1 comes on when I play a wav file via aplay or if I use speaker-test but absolutely no sound out. The DAC is connected straight to my amp and I re-tested the amp several times.
Played around with alsamixer settings, re-installed DietPi but nothing.
There seem to be some errors in dmesg but it seems to work at the end?:
[ 3.647815] snd-allo-boss-dac soc:sound: ASoC: CODEC DAI pcm512x-hifi not registered - will retry
[ 3.647833] snd-allo-boss-dac soc:sound: snd_soc_register_card() failed: -517
[ 3.855964] snd-allo-boss-dac soc:sound: ASoC: CODEC DAI pcm512x-hifi not registered - will retry
[ 3.855983] snd-allo-boss-dac soc:sound: snd_soc_register_card() failed: -517
[ 3.872582] snd-allo-boss-dac soc:sound: ASoC: CODEC DAI pcm512x-hifi not registered - will retry
[ 3.872600] snd-allo-boss-dac soc:sound: snd_soc_register_card() failed: -517
[ 3.991832] snd-allo-boss-dac soc:sound: pcm512x-hifi <-> 3f203000.i2s mapping ok
Also, there is this acrid smell coming from the boards (can’t tell which one).
Any ideas on what could be wrong? Is there something somehow muting the DAC?
Thanks!
Yes, you’re not using Volumio
Chapeau, Sir, Chapeau 
Fair enough 
Latest version of volumio installed, DAC setup, same issue - DAC LED1 lights up volume is up, no sound out of speakers.
Here are the relevant dmesg output:
[ 10.648520] snd-allo-boss-dac soc:sound: ASoC: CPU DAI (null) not registered
[ 10.648544] snd-allo-boss-dac soc:sound: snd_soc_register_card() failed: -517
[ 10.651826] snd-allo-boss-dac soc:sound: ASoC: CODEC DAI pcm512x-hifi not registered
[ 10.651852] snd-allo-boss-dac soc:sound: snd_soc_register_card() failed: -517
[ 10.901674] snd-allo-boss-dac soc:sound: pcm512x-hifi <-> 3f203000.i2s mapping ok
[ 10.902606] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 39.667250] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 39.702097] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 39.702979] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 49.958483] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 90.625658] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 90.641145] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 90.642445] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 110.158480] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 327.267387] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 327.281640] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 327.283256] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 370.898483] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 437.482611] snd-allo-boss-dac soc:sound: Muting DAC using GPIO6
[ 437.496841] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
[ 437.498126] snd-allo-boss-dac soc:sound: Un-muting DAC using GPIO6
asound status during playback:
volumio@volumio:~$ cat /proc/asound/BossDAC/pcm0p/sub0/hw_params
access: RW_INTERLEAVED
format: S24_LE
subformat: STD
channels: 2
rate: 44100 (705600/16)
period_size: 4410
buffer_size: 22050
and aplay output:
volumio@volumio:~$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: BossDAC [BossDAC], device 0: Boss DAC HiFi [Master] pcm512x-hifi-0 []
Subdevices: 0/1
Subdevice #0: subdevice #0
Hi Allo,
I have Boss DAC and it works well with my pi 2 & 3. Now, i want to try my Boss DAC with pi zero 1.3. Can it work until now?
I have purchased a used boss. Great sound! Works with my headphones connected directly to the dac
I’m gradually starting to understand the audiophile thing 
hello folks,
I’m newcomer, just trying to recognize how to set up my first hifi gear. Apologies for my questions, if self evident to others.
This I2S thing is confusing me. I have learned before that I2S is not standard. I know at least one streamer which provides I2S using HDMI connector. It is supposed to pair with just certain DACs (in this case Holo, Audio-gd…) supporting that I2S streamer. I just ordered Allo BOSS player. Now, how should I take account this I2S thing when I choose streamer or preamp? What type of preamp I should choose?
regards
andy
Your Boss DAC takes the I2S signal from your Pi (or Sparky SBC) and generates the needed analog signal to feed your (pre)amp.
Are you looking for just an amp with no build-in pre-amp? Or (more common) for an amp that has multiple inputs (into the pre-amp part)? Just Stereo (as the Boss can only supply a stereo analog signal) or also with surround capabilities?
Very important is also, what speakers do you have? Start with the speakers and work your way back.
You don’t need a seperate DAC (like audio-gd or others) as the Boss does your Digital-Analog-Conversion
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Yes, I know Boss is DAC. Audio-gd is not just DAC, they have very good preamp too.
My plan was to have active speakers (not yet there…) which preamp would feed directly.
Boss player bundle seem to have “Allo Volt Amp header” too… whatever it does mean?
best
andy
You can add an amplifier (volt) directly on top.
I have an Audio-gd NFB11(.32) myself which is a very nice Dac AND pre-amp. Feeding it over USB using a Pi was not very succesful so now I use SPDIF (coaxial not optical!).
I have been looking into using the variable pre-amp output as a direct input for a direct amp, but haven’t been able to find a good amp.
Using the fixed output of the audio-gd into a pre-amp input (that can handle the signal level of 5volt) seems to give more options.
My suggestion if you like to audio-gd as pre-amp for your active speakers (smart idea), than look at an SPDIF source for the Pi like HifiBerry Digi+ Pro or Allo DigiOne. And use the DAC of the Audio-gd.
Btw: you can use the I2S header on the HFB Digi+ Pro also as an direct input to some Audio-gd devices Look at the site from Magna Audio for examples.
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Ok, thanks. I’ve been considering A-gd NFB-1 pre myself. On the source side I would not mind to mess with PC/NAS. So, streamer should be storage. It is Magna’s streamer providing IIS transport. But isn’t Boss expecting IIS input?
Btw: Ag-d will have new single ended amp soon (in a NFB1 enclosure like they said). ask Magna.
regards
andy
Hi,
I’ve just found and ordered this bad boy.
Would it be possible to run it directly into a power amplifier? If so, what specs should I look at - impedance or sensitivity or something else - and what values would be optimal?
And - if I only play 16bit files, can I make the board upgrade those to 24bit or higher, so I can lower the volume digitally without loss of information?
A lot of questions, thanks a lot for any input. Looking so much forward to receiving it.
Yes It is supposed to feed directly into an amp or pre-amp. Spec say 2.1 Vrms max output. So it depends on your amp.
Also, making an assumption on your question below that you only want an amp without volume control, active speakers can be an option as well.
I don’t think it is a feature of the board to re-sample to 24 bit (it would just add zeroos?), but software volume control is an option in Volumio.
But I think it will always ‘cost’ you some information compared to hardware (analog level or at IC via I2C). But as far as I remember, look it up yourself to verify, the Boss support hardware (at the IC) volume control which is implemented in the driver Volumio uses. Which means you should be fine using Volumio to do your volume control
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Allo Boss can handle 32/384. In volumio you have also the feature to resample audio to 16/26/32 bit 44.1-384 kHz.
And simplified if a dac is not a NOS dac, it oversamples everything to internal bit/freq. In other forum I saw the Allo boss does it to 24/384 and few people think if your software resample the input into this freq it bypasses boss internal conversion and you get better result. Don’t know, maybe allo has an answer for this idea.
Back to the original question:
If you oversample the bit depth you are able to reduce volume digital (software volume control) much more before you lose quality. Allo Boss has hardware volume control and volumio recommends to use this instead of software volume control.
(My experiences are that digital volume control can be as good as the hardware volume control but this is another topic.)