Clip+ hardware noise

[Milesdust]

Hi all, Rockbox is absolutely brilliant! Except I often hear hardware noise on three occasions: When the fade in/out effect is used on pausing/starting a track, when the disk is beign accessed heavily, and when turning the mp3 player off.

It sounds like a buzzing noise. Is this an issue that could be sorted out?

[bertrik]

The buzz at the fade in/out effect is caused by the volume control in the audio hardware. The audio hardware has a built-in "auto-fading" mechanism that is currently enabled. Somehow each fade step causes a little click, and together in rapid succession these clicks sound like a buzz. If the auto-fading mechanism is disabled, it sounds like a big click at the end of fade-out. I think we're still not doing something right in rockbox with respect to that.

The noise on accessing disk is still a bit of a mystery. I can't hear it on my player, but other people can on their players. Can you try rockbox release 3.8.1 or a current build and see if it got better? It may also vary between "variants" of the clip+. You can find out which variant (0 or 1) you have by going into Menu System / Debug / View hardware info.

I don't know what the noise is on power-off. It could be same as the fade in/out noise.

[LivArt]

Try to switch off Replaygain. I think it's better, but it's still here.

[saratoga]

Try to switch off Replaygain. I think it's better, but it's still here.

That just makes things louder. 

[keyb_gr]

The noise on accessing disk is still a bit of a mystery. I can't hear it on my player, but other people can on their players.

I can hear some a few seconds after the beginning of a new track with sufficiently sensitive in-ears (Shure SE420). (Some low-level ticking and buzzing that only lasts a short while.) It's not at all dramatic though, especially compared to the permanent loud ticking on the ClipV2. This is with a "variant 1" Clip+.

I don't know what the noise is on power-off. It could be same as the fade in/out noise.

Whatever it is, it apparently acts like a current source. There's not that much on the SE420s, but it's a pretty healthy crack on HD590s or a line-level input.

If I were to venture a guess, I'd say the headphone amp is operating too long, maybe right up to the point where the negative supply charge pump shuts down.