Dears,
I would have a few questions with regards to the AMP+
- is it 2 X 25W or 2 X 12,5W?
- is that at 4 ohm or 8 ohm?
- does it have a hardware or software volume control (e.g. in Volumio)?
- what is the resolution of the volume control (how many bits)?
Thank you in advance
Peter
Date
Votes
7 comments
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HiFiBerry team Hi Peter,
it is about 2x25W peak power into 4 Ohm and about 25W continues power over both channels together. This is a bit complicated to explain as music signals behave different than sine waves. At 8 Ohm, the maximum power is lower.
It has a hardware volume control with 0.5dB resolution.
Best regards
Daniel -
ppataki Thank you Daniel! -
Georges Rossopoulos Guys,
I have plugged one unused harman/kardon speaker to my amp+. (spare from my 7.1 home studio)It works fine but the maximum volume is quite low...
I have no idea what the speaked impedance is. A regular voltmeter shows 7 ohm...Should I consider buying proper 4 ohms or is there an additional setting to the one in Squeezebox ?
(I had the impression the "one note" output with sox was louder...)Cheers
Georges
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HiFiBerry team Hi Georges,
7 Ohm is ok, the efficiency of the speakers has much more impact on the volume than the impedance. But even it the speaker isn't very efficient, the maximum output volume should be quite high.
You should log into the system and check the volume settings. "amixer" will show this.
Best regards,
Daniel -
Georges Rossopoulos Thanks Daniel!
It looks like I still have a lot to learn about the Pi and the Hifiberry Amp+ settings ! dooh!1st I checked the list of devices:
**** 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: sndrpihifiberry [snd_rpi_hifiberry_amp], device 0: HifiBerry AMP HiFi tas5713-hifi-0 []
Subdevices: 0/1
Subdevice #0: subdevice #0which translates into the Squeezelite sound card selection to a huge list:
equal - equal,
plugequal - Equalizer for plughw:0,0,
default - bcm2835 ALSA, bcm2835 ALSA - Default Audio Device, CARD=ALSA
sysdefault - bcm2835 ALSA, bcm2835 ALSA - Default Audio Device, CARD=ALSA
dmix - bcm2835 ALSA, bcm2835 ALSA - Direct sample mixing device, CARD=ALSA,DEV=0
dmix - bcm2835 ALSA, bcm2835 IEC958/HDMI - Direct sample mixing device, CARD=ALSA,DEV=1
dsnoop - bcm2835 ALSA, bcm2835 ALSA - Direct sample snooping device, CARD=ALSA,DEV=0
dsnoop - bcm2835 ALSA, bcm2835 IEC958/HDMI - Direct sample snooping device, CARD=ALSA,DEV=1
hw - bcm2835 ALSA, bcm2835 ALSA - Direct hardware device without any conversions, CARD=ALSA,DEV=0
hw - bcm2835 ALSA, bcm2835 IEC958/HDMI - Direct hardware device without any conversions, CARD=ALSA,DEV=1
plughw - bcm2835 ALSA, bcm2835 ALSA - Hardware device with all software conversions, CARD=ALSA,DEV=0
plughw - bcm2835 ALSA, bcm2835 IEC958/HDMI - Hardware device with all software conversions, CARD=ALSA,DEV=1
default - snd_rpi_hifiberry_amp, - Default Audio Device, CARD=sndrpihifiberry
sysdefault - snd_rpi_hifiberry_amp, - Default Audio Device, CARD=sndrpihifiberry
dmix - snd_rpi_hifiberry_amp, - Direct sample mixing device, CARD=sndrpihifiberry,DEV=0
dsnoop - snd_rpi_hifiberry_amp, - Direct sample snooping device, CARD=sndrpihifiberry,DEV=0
hw - snd_rpi_hifiberry_amp, - Direct hardware device without any conversions, CARD=sndrpihifiberry,DEV=0
plughw - snd_rpi_hifiberry_amp, - Hardware device with all software conversions, CARD=sndrpihifiberry,DEV=0I am using "default", which works fine.
I checked my /etc/asound.conf, which also gives me more than I expected..
ctl.!default {
type hw
card 0
}
pcm.equal {
type plug;
slave.pcm plugequal;
}
ctl.equal {
type equal;
module "Eq10";
}pcm.plugequal {
type equal;
module "Eq10";
slave {
pcm "plughw:0,0";
}
hint {show on;description "Equalizer for plughw:0,0"}
}Anyway, I tried your suggestion with amixer, which was not quite readable for me!
pi@max2play:~ $ amixer
Simple mixer control 'PCM',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback 100 [97%] [1.00dB] [on]And then I found alsamixer, which, in putty, opens a semi-graphical tool,
where I could visually adjust some mysterious levels ( Master and Channels ),
which indeed boosted the volume up !So many thanks for the hint which lead my search to a solution.
However, I'd be happy if you could suggest some literature/blog where I could
better understand why there are so many cards, and how to manage the sound system on the PI !By the way, I am using max2play to drive the Amp+ and setup my Squeezebox.
Once more confident with these settings I'll go ahead and get my additional Pis and Amps
for my multiroom !As far as quality is concerned, the Amp+ and harman/kardon speakers is phenomenal !
Kind regards
Georges
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HiFiBerry team Hi Georges,
the problem here is that you still have the onboard sound enabled as the first sound card. Therefore "amixer" uses it. Just remove the line
dtparam=audio=on
from your config.txt file and you should be fine.
The other stuff are ALSA plugins added by the distributions you're using. Unfortunately I don't know a good document that explains the ALSA subsystem and the plugin concept. You will find a lot of stuff with a Google search, but you need to get the information from a lot of different places.
Best regards,
Daniel -
Georges Rossopoulos Again many thanks for your support!
My /boot/config.txt reads:
...
# Enable audio (loads snd_bcm2835)
dtparam=audio=on
gpu_mem=128
dtoverlay=hifiberry-ampCommenting the dtparam line does indeed disable the onboard card,
and amixer returns:
pi@max2play:~ $ amixer
Simple mixer control 'Master',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 248
Mono: 201 [81%]
Simple mixer control 'Channels',0
Capabilities: volume
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: 0 - 248
Front Left: 215 [87%]
Front Right: 215 [87%]
pi@max2play:~ $I guess "Master" is for "global" adjustment,
while "Channels" allows for left/right setup.Thanks for your excellent and fast support Daniel!
Kind regards
Georges
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