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#1 2010-08-07 18:34:48

lost eden
Member
Registered: 2008-01-01
Posts: 62

no volume control with ALSA & new DAC

I've just bought a new USB DAC (iBasso D4 Mamba, dual Wolfson WM8740 DAC chips) to replace my old USB DAC (Firestone Audio Fubar III, Burr-Brown TI PCM2702). A USB DAC is essentially just an external USB soundcard. With my old DAC, alsamixer presented two sliders; 'master' & 'PCM'; I could control the volume using 'master'. However with my new DAC, alsamixer only presents one slider; 'PCM'. Adjusting 'PCM' does absolutely nothing to the volume. This means that the volume is always at 100%. This is a problem, because the DAC has a recognised flaw, where a lack of voltage to the chips themselves means it clips if it is fed 100%. So I need to drop the volume to ~80% but obviously I can't do this without a functioning volume control!

Another thing that worries me is my /proc/asound/cards entry. I'm not sure why it mentions 'Burr-Brown from TI', because that's not what my new DAC is. I'm worried that drivers/settings from my old DAC have been preserved & I want all traces of it completely purged.

[cj@yuzuki ~]$ cat /proc/asound/cards 
 0 [default        ]: USB-Audio - USB Audio DAC   
                      Burr-Brown from TI               USB Audio DAC    at usb-0000:00:1a.0-2, full s

Some other output that might be useful.

[cj@yuzuki ~]$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: default [USB Audio DAC   ], device 0: USB Audio [USB Audio]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
[cj@yuzuki ~]$ lsmod|grep '^snd' | column -t
snd_hda_intel       21906  0
snd_seq_dummy       1447   0
snd_hda_codec       76595  1   snd_hda_intel
snd_seq_oss         28928  0
snd_seq_midi_event  5420   1   snd_seq_oss
snd_seq             50530  5   snd_seq_dummy,snd_seq_oss,snd_seq_midi_event
snd_pcm_oss         39096  0
snd_usb_audio       78639  2
snd_pcm             71653  5   snd_hda_intel,snd_hda_codec,snd_pcm_oss,snd_usb_audio
snd_timer           19660  2   snd_seq,snd_pcm
snd_page_alloc      7201   2   snd_hda_intel,snd_pcm
snd_hwdep           6126   2   snd_hda_codec,snd_usb_audio
snd_usb_lib         17362  1   snd_usb_audio
snd_rawmidi         19235  1   snd_usb_lib
snd_seq_device      5241   4   snd_seq_dummy,snd_seq_oss,snd_seq,snd_rawmidi
snd_mixer_oss       16932  1   snd_pcm_oss
snd                 57225  17  snd_hda_intel,snd_hda_codec,snd_seq_oss,snd_seq,snd_pcm_oss,snd_usb_audio,snd_pcm,snd_timer,snd_hwdep,snd_usb_lib,snd_rawmidi,snd_seq_device,snd_mixer_oss
[cj@yuzuki ~]$ cat /proc/asound/card0/pcm0p/sub0/hw_params 
access: RW_INTERLEAVED
format: S16_LE
subformat: STD
channels: 2
rate: 44100 (44100/1)
period_size: 5513
buffer_size: 22050

[cj@yuzuki ~]$ cat /proc/asound/card0/pcm0p/sub0/sw_params 
tstamp_mode: NONE
period_step: 1
avail_min: 5513
start_threshold: 16537
stop_threshold: 22050
silence_threshold: 0
silence_size: 0
boundary: 6206523236469964800

[cj@yuzuki ~]$ cat /proc/asound/card0/pcm0p/sub0/info 
card: 0
device: 0
subdevice: 0
stream: PLAYBACK
id: USB Audio
name: USB Audio
subname: subdevice #0
class: 0
subclass: 0
subdevices_count: 1
subdevices_avail: 0

[cj@yuzuki ~]$ cat /proc/asound/card0/pcm0p/sub0/status 
state: RUNNING
owner_pid   : 3624
trigger_time: 12467.886130753
tstamp      : 13222.343241858
delay       : 20066
avail       : 2470
avail_max   : 21026
-----
hw_ptr      : 33284480
appl_ptr    : 33304060

I've gotten myself mightily confused trying to fix this, so any help would be greatly appreciated!

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#2 2010-08-07 18:42:35

skunktrader
Member
From: Brisbane, Australia
Registered: 2010-02-14
Posts: 1,543

Re: no volume control with ALSA & new DAC

You could try renaming /etc/asound.state to /etc/asound.state.backup and then running alsactl store to regenerate it.

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#3 2010-08-07 18:45:45

lost eden
Member
Registered: 2008-01-01
Posts: 62

Re: no volume control with ALSA & new DAC

skunktrader wrote:

You could try renaming /etc/asound.state to /etc/asound.state.backup and then running alsactl store to regenerate it.

I already tried deleting /etc/asound.state & then restarting alsa, to no success. I just tried explicitly running alsactl store anyway, but again no luck.

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