Error when recording using Zoom h4n

I tried to record using Zoom h4n as an audio interface.
It records properly the first track.
When I record second track there is an error.
For short periods of time there is no sound recorded.
Sound(0,066 s), no sound (0,020 s), sound(0,066 s), no sound (0,020 s)…
using Soundblaster Live all is fine.

I attached samples.

I am using:
Audacity ® 2.0.0 (Unicode)
Ubuntu 12.04

I installed Pulse Audio, now recording doesn’t work at all in Audacity.

I checked it works well under Ardour (JACK Audio)

PulseAudio is installed in Ubuntu by default :confused:

Have you tried recording in Audacity with Jack?
(Note there is a bug in Audacity - When using Jack, do not activate the recording meter before Audacity has been put into Record mode at least once, otherwise Audacity is likely to crash).

To use Audacity with Jack, start Jack before you launch Audacity. Then select “Jack audio system” as the “host” in the device toolbar.