I was doing a bunch of recording last summer. When I could run the laptop on batteries it worked quite well but if I plugged in the AC adapter there was so much noise it was unusable. And I was using a StarTech card but I don't remember the "Speed Dragon", just cm106-like. I picked up a couple cheap Chinese ones on Aliexpress for ~$7 each that work just about the same (also cm106-like) since I don't use the microphone inputs I bought the Star Tech for. For playback several times a week I run the Chinese one into a small power amp and a pair of speakers for listening to mp3s for an hour or two.
But what kind of noise is it? On a Raspberry Pi using hdmi sound to a monitor, which then goes to an old analog pair of speakers I get what I'd call "digital noise", it's like putting a radio near a computer. Sometimes it stops if I close Firefox, but I think it's because a sound server shuts down, other things can make the same noise. Sound is an analog world mostly, digital stuff can inject noise into it. SPDIF might be immune to it. On my Pinebook Pro with AC adapter I get mostly old-fashioned hum, but higher than 60 or 120 Hz, it's from a switchmode power supply. I think the pitch changes with the current load on it too. On 5/11/21, Jim Erickson <jimeric...@gmail.com> wrote: > i had the same problem with C-Media usb dac's. so i switched to StarTech > and have had no problems since. relevent portion of dmesg follows: > > uaudio0 at uhub5 port 2 configuration 1 interface 1 > "Speed Dragon USB Advanced Audio Device" rev 2.00/1.04 addr 9 > uaudio0: class v1, full-speed, sync, channels: 2 play, 2 rec, 9 ctls > audio0 at uaudio0 > uhidev3 at uhub5 port 2 configuration 1 interface 3 > "Speed Dragon USB Advanced Audio Device" rev 2.00/1.04 addr 9 > uhidev3: iclass 3/0, 1 report id > uhid3 at uhidev3 reportid 1: input=15, output=15, feature=0 > > > -- ------------- Education is contagious.
