Noise on left channel

Hi all, I’m using the latest development version of Ardour on Ubuntu 20.04, so apparently shouldn’t report this as a bug - just wondering if it’s just me… I’ve just finished a marathon recording session, all was good. Then I loaded a template, from the previous session, and started the next recording. All was good. Then, after perhaps an hour, I started getting white noise (around 5kz) on the left channel through my headphones, the right channel was fine. I disconnected everything, but still there. I checked all the connections in JACK and all were connected as expected, eventually I tracked it down to arming record (on any track), with record off all was sweetness and light, with it on - hiss. With my guitar or bass plugged in, both have, in addition to the hiss, a pretty quiet heavily over-driven tone in the background of the left output only, but I have no plugins in use (except Fader and GxTuner - removing the tuner made no difference). So it’s definitely internal to Ardour. I then quit Ardour, re-loaded the session, and still there. The I powered down the computer and switched it back on - bingo, no noise. Anyone know what the cause might be?

Sounds like you only have problems when you use the audio inputs of the sound device. A ground loop can cause noise on the input and a poor laptop power supply can do it also. If this is a laptop try to disconnect the power supply and run on the battery. Also make sure all audio devices: guitar effects, direct boxes, amplifiers and the DAW computer are physically connected to the one and same power outlet in the room. Use an extension cord with many outlets if necessary.

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Yep, I’ve got it all in one plug, it’s not mains hum or floating earth, not least as it went away on a complete power-down/power-up cycle. It sounds like, and I’m only guessing really, some connection internally has not correctly released the hardware. I just thought I’d mention it in case anyone else had the same. It hasn’t come back so I have a feeling it was to do with the previous recording session, but with 25 tracks… Thanks for replying :slight_smile: