In article ,
Sjouke Burry wrote:
On 13-11-2018 0:18, Adrian Tuddenham wrote:

Oscillating a bit somewhere?

That's what I was thinking, but why only on the left channel? Both
recorders behave the same way.


Spread in components, differences in layout causing parasitic caps an
inductances
to vary, take your pic.

Possibly there's some occasional switching noise on a digital or power
trace, which is coupled more effectively into the left-channel analog
trace going to the ADC? The left-channel trace might actually be
acting to shield the right-channel trace from some of the noise.