I2s and usb dac problems ES9018 and PCM1794

Hi Volumio crew,

Last week I bought a raspberry pi for playing with volumio.
I like the project very much.
Its working fine with a HDMI dac.

But when I connect a usb dac with tenor TE7022 usb receiver-> ES9018 I’m having a lot of stuttering.(like a buffer is going empty and then fills again)(volumio beta 1.1)

Then I tried my other I2S dac witch I made with a SCR4192 (for putting in the clock signal.)->PCM1794.(Volumio beta 1.0)
Its playing very good but when I push stop or pause it starts ticking. Every 1-2 second a tick.

Then I tried the piCorePlayer this one also works fine over i2s but has no ticking when I push stop or pause.

Could there be something wrong with the I2S driver?

Has this ticking been solved? I also have this issue with a PCM 1794 chip.