Pi add-on sound cards?

Discussion in 'RFinderPi - Open Source radio interface based on R' started by KX4OM, Dec 25, 2015.

ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: L-Geochron
ad: abrind-2
ad: MessiPaoloni-1
ad: Left-3
ad: Left-2
ad: HRDLLC-2
  1. KX4OM

    KX4OM Ham Member QRZ Page

    I've got a Pi B+ that I plan to use for digital modes, operating portable as well as in the shack. I decided that after having owned the Pi for 365 days now, waiting for an inspiration. Based on reports from some sources, the Pi's native sound isn't that good a performer. The OP that did the below Youtube video on a Pi-based field setup for digital modes says the Signalink USB works fine for him. Has anyone tried a Pi add-on sound card like the HiFiBerry DAC+ or DAC+ Pro ? It stacks on the Pi, and they also sell several cases to contain both units, both metal and plastic versions.

    The excellent instructional video by KM4BLG on how to do a field setup:

    The HiFiBerry site:

    Ted, KX4OM
  2. K6CLS

    K6CLS Ham Member QRZ Page

    I use $10 USB soundcards on my RPis and they work just fine. Digimodes do not need a hi-fi soundcard. JT65 samples at 11025bps, 1/4 of the 44kbps "CD" quality rate.

    I am not sure a hi-fi card is needed for (SSB/AM/FM) voice, for example IRLP or Echolink.
  3. KX4OM

    KX4OM Ham Member QRZ Page

    I'll be using fldigi with an assortment of non-interfaced radios; i.e., no modern Elecraft, Yaesu, Icom, etc., rather homebrew rigs and a Tempo 2020 and HW-101 with mic input and speaker/headphones out. I have a homebrew sound card interface that uses transformers in both directions for isolation. My current digital modes PC is an old Fujitsu Lifebook running Windows 98. The Pi will save a lot of room on the desk or outdoor table with a 4.3" composite monitor, and it has a heckuva lot more horsepower than the trusty Lifebook, whose battery pack has died.
  4. KX4OM

    KX4OM Ham Member QRZ Page

    Update: I bought an $8 USB sound card from Amazon with a CM-119 chip (confirmed to be Pi compatible.) I found a lot of support material, so I'll be editing ALSA and some other files to set it up.
  5. GJ7RWT

    GJ7RWT Ham Member QRZ Page

    Take a look at this page


    I use the 3rd one down, it does everything it needs to.

    hope this helps.

    DE Andy
  6. KF5FEI

    KF5FEI Ham Member QRZ Page

    Haven't tried my USB sound dongles with the Pi yet, but they work well for digi modes in Windows, and can be had for pretty cheap. I think I paid about $4 each for these a few years ago, when I discovered my Samsung netbook had a sound chipset issue and would not work with any digi software.
  7. KM4BLG

    KM4BLG Ham Member QRZ Page

    Thanks for the complement on my video! I use a homebrew interface for my Alinco DX-70. I use a simple serial port keyer for keying (transistor to RTS pin, KM4CFT can tell you more about that) along with a homemade cable that connects the keyer circuit and an audio line from the out on my computer to the radio. That covers transmit. For receive, I simply use an aux cable from the speaker jack to line in. I've only tried it once on the Pi, but I got this to work by plugging my serial keyer into a USB to serial adapter and handled the audio with a cheap USB audio dongle. I used this USB sound card:


    Although, it has a rather weird issue. If you start FLDigi or some other audio application without audio actively coming in on line-in, it won't recognize the line-in side. If there is audio playing, there is no issue. So what I do, is I turn my radio on with squelch off and volume up before starting FLDigi. I have yet to figure out why this is like this. I even tried another USB sound card. Same result. So I'm thinking that it is somewhere in the OS.

    Let me know if you need any help and I'll be happy to help you as best I can.
  8. KX4OM

    KX4OM Ham Member QRZ Page

    I looked up the Daffodil, and I couldn't find what chip it uses. One reviewer on Amazon (Dan) wrote this:

    "I needed a better-than-onboard DAC with mic input for my Raspberry Pi, and this fits the bill nicely. ALSA drivers can drive it without hesitation, and it plays nicely with MPD.

    "ALSA does need to be tuned for latency and preference to use the DAC without filling your card with huge log files.

    "To the file "/etc/modprobe.d/alsa-base.conf" add:

    "options snd-usb-audio nrpacks=1

    "and comment out:

    "options snd-usb-audio index=-2"

    The USB card that I bought uses a CM-119 chip that others have reported needing new files and file modifications due to ALSA. I haven't made a concise list for testing yet. Also, the version of Raspbian has something to do with it.

    Ted, KX4OM
  9. KM4BLG

    KM4BLG Ham Member QRZ Page

    Thanks. Yea, oddly enough I haven't had any trouble with audio output, but input has that weird issue. I'll try this and see if that fixes it. Might be a couple of days before I can get to it though. I'll let you know how it turns out.
  10. AD0AC

    AD0AC Ham Member QRZ Page

    Has anyone had any success getting the Signalink USB to work under Raspbian Jessie? It appears to work in other distros on regular PC hardware, but it is not showing any capture hardware under alsamixer. I can plug a generic USB sound card into the Pi and it seems to be working, but I really want to use the Signalink because it has the built-in PTT control.

Share This Page