Ticket #274 (new bug)

Opened 5 months ago

Last modified 4 months ago

strange 50hz hum fading in after some time - saffire le

Reported by: furenku Assigned to:
Priority: critical Milestone:
Component: generic Version: FFADO 2.0.0
Keywords: hum, saffire, noise Cc:
The device the bug applies to:

Description

After an upgrade to Ubuntu 10.04, I finally got my Saffire LE working; however, after a couple minutes of working fine, a strange hum (50 hz) that sounds like PM fades in, until it becomes quite loud.

Stopping Jack makes it stop, but when restarting it, its there. The humming stays when jack restarts even if i disconnect the interface from the computer or even disconnect it from power and reconnect it to power and FW.

after the first appearance of the hum, it may even come when the soundcard is disconnected from firewire... however after rebooting, and before starting jack, there's absolutely no hum.

Any ideas, where this could come from?

I already tried jack with another sound card (edirol fa-101) and that worked without problems, and without any xruns.

maybe, since the hum is 50 hz, it has something to do with the power supply for the saffire? i'm not using the factory one, but the one i have definitely fits the specs.

I'm using Ubuntu 10.04 with a -rt kernel.

Thanks in advance.

Attachments

furenkuFfadoTicket.zip (2.7 kB) - added by furenku on 04/22/10 17:49:30.
jack log & ffado diag log

Change History

04/22/10 17:49:30 changed by furenku

  • attachment furenkuFfadoTicket.zip added.

jack log & ffado diag log

04/27/10 12:57:03 changed by arnonym

Just a stupid question: You confirmed that your machine works correctly with a different device but produces 50Hz-hum with the saffire le. Did you try the saffire on another machine? On another OS?

If both work, the only reason I could faintly imagine would be the difference in the channel-count braking ffados neck on your machine. But that would result in something different then 50Hz. And its hardly possible as both the saffire-le and the fa-101 use the same chipset with the same number of maximum channels (10 ins and 10 outs)...