Ok, first delete the file /etc/modprobe.d/alsa-base.conf Raspbian Jessie does not use this config file like Wheezy did.
To find what address your device uses you need to first enter the command aplay -l this shows all audio output devices, and their address. For example, my USB sound card comes up as device 1 in the output which looks like this.
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 1: Device [USB PnP Sound Device], device 0: USB Audio [USB Audio]
Subdevices: 0/1
Subdevice #0: subdevice #0
Now, to set the device to your default card you will need to edit the file /usr/share/alsa/alsa.conf with the command sudo nano /usr/share/alsa/alsa.conf scroll down until you find the lines
defaults.ctl.card 0
defaults.pcm.card 0
and change them to (if your device is also listed as device 1, if not change the 1 to whatever address it was listed at)
defaults.ctl.card 1
defaults.pcm.card 1
Explanation: USB sound cards are registered as card 1 on Raspbian Jessie. On Wheezy they would be registered as card -2 by default and editing /etc/modprobe.d/alsa-base.conf would change that.
I do not know if this next step is necessary but without it my card wouldn't work.
Create and edit the file ~/.asoundrc by using the command sudo nano ~/.asoundrc and change it so that it only reads this:
pcm.!default {
type hw
card 1
}
ctl.!default {
type hw
card 1
}
Now your default audio out (speakers) and audio in (mic) are your usb device.
.conf. It's what's in them that counts. – goldilocks Dec 23 '15 at 15:13options snd_bcm2835 index=1. – goldilocks Dec 23 '15 at 15:21device_tree=(with nothing after it) in/boot/config.txtto disable it, then reboot again. If that doesn't work, you might as well remove that line fromconfig.txtso you do not forget later. – goldilocks Dec 23 '15 at 15:54systemdas its "init" by default; pulseaudio is a separate thing to Alsa, and systemd and pulseaudio share the same "Father" so I suspect that if PA is around systemd will be interacting with it. I may however be acting as a FUD-merchant here... 8-P – SlySven Dec 23 '15 at 18:01