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odw199
2018-02-01, 04:47
Hi,

Last night I put together a new player, a Raspberry Pi 3 with Allo Boss DAC, running piCorePlayer. The plan was for this to be a small player that would feed an Audio Pro Addon T3 in the bedroom or study. This would be a nice compact player giving decent enough sound for casual listening.

I was a little short of time after putting the case together (should have watched the video properly rather than assuming I could just fudge my way through) so I quickly hooked it into my main system to check it was all working.

The main system is an SB3 -> analogue out to Onkyo A 9010 amp -> KEF LS50 speakers

Therefore the pi + Allo Boss was a simple drop in replacement for the SB3.

It turns out (to my ears anyway) the pi + Allo Boss combination outshone the SB3! It's now going to be the source for my main system with the SB3 relegated to feed the T3.

One question I do have, with the SB3 I always set volume to 100% and let the amp take care of volume adjustment. Should I be doing the same with the Allo Boss to give the cleanest output or am I better finding a volume sweet spot for the Allo Boss (around say 75%)?

Cheers

Man in a van
2018-02-01, 06:55
Nice set-up

i did a bit of a google and found this reply on the Mod my pi form

https://forum.modmypi.com/technical-support/allo-boss-raspberry-pi-master-dac-t1369-10.html

Best to leave it at 0db I think


ntroduction
============

This directory contains Device Tree overlays. Device Tree makes it possible
to support many hardware configurations with a single kernel and without the
need to explicitly load or blacklist kernel modules. Note that this isn't a
"pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices
are still configured by the board support code, but the intention is to
eventually reach that goal.

On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By
default, the Raspberry Pi kernel boots with device tree enabled. You can
completely disable DT usage (for now) by adding:

Code: Select all
device_tree=


to your config.txt, which should cause your Pi to revert to the old way of
doing things after a reboot.



Name: allo-boss-dac-pcm512x-audio
Info: Configures the Allo Boss DAC audio cards.
Load: dtoverlay=allo-boss-dac-pcm512x-audio,<param>

Code: Select all
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
Digital volume control. Enable with
"dtoverlay=allo-boss-dac-pcm512x-audio,
24db_digital_gain"
(The default behaviour is that the Digital
volume control is limited to a maximum of
0dB. ie. it can attenuate but not provide
gain. For most users, this will be desired
as it will prevent clipping. By appending
the 24db_digital_gain parameter, the Digital
volume control will allow up to 24dB of
gain. If this parameter is enabled, it is the
responsibility of the user to ensure that
the Digital volume control is set to a value
that does not result in clipping/distortion!)
slave Force Boss DAC into slave mode, using Pi a
master for bit clock and frame clock. Enable
with "dtoverlay=allo-boss-dac-pcm512x-audio,
slave"



so editing the config.txt file to include the line

Code: Select all
dtoverlay=allo-boss-dac-pcm512x-audio, 24db_digital_gain

should allo raspbian to load the correct modules so that it can see the DAC as a device for you to send sound to.

Note that this is reffering to the quoted OP's question, not to yours :confused:

you can check in th ALSA settings or Audio Card Control, maybe on the picore squeezelite tab

ronnie

odw199
2018-02-01, 07:47
Thanks for the reply.

I think a chunk of that text is also in the piCorePlayer configuration pages for the Allo Boss. Sounds like leaving the 24db setting well alone and setting volume to 100% is the way to go.

The setup is proving excellent for the money (OK, the speakers weren't that cheap but cheap compared to a lot of things out there!)

Cheers

paul-
2018-02-01, 11:01
volume control and the gain boosters are all software adjustments.

Leave the volume at 100% (0 db) and the extra stuff turned off.