Can I have an question why the -sin wawe looks like that?

Parameters are: f=2 kHz, Uef = -4 to 4 V

 

A quick guess - C0 is too small. The time constant needs to be of the order of at least 10 cycles.

 

A quick guess - C0 is too small. The time constant needs to be of the order of at least 10 cycles.

Can I have it in the same value as C6, C7 = 47 nF?

 

Try it and see.
Too big -> amplitude will take longer to settle
Too small -> distortion.

 

Your circuit has a few problems:

 

Your circuit has a few problems:

After change of all noticed parameters it's even worse

 

What values did you use for R1, R3 and R8? Did you get the correct pinout for the JFET? What is the voltage on the gate?

 

Your new circuit is clipping like crazy due to too much gain.
The Jfet is not properly reducing the gain.
Please post the new schematic with parts numbers.

 

Your new circuit is clipping like crazy due to too much gain.
The Jfet is not properly reducing the gain.
Please post the new schematic with parts numbers.

 

Try it like this: