FM stereo receiver distortion

[Barry Duggan]

Hi,

I have a broadcast FM (mono) receiver which works well, with good audio 
and clean traces in the Time Domain. See 
https://wiki.gnuradio.org/index.php/File:USRP_FM_fg.png

Then I made a stereo version. See 
https://wiki.gnuradio.org/index.php/File:USRP_FM_stereo_fg.png  Using 
it, the sound has a distortion but does not have any audio underruns. 
The traces in the Time Domain have a lot of "fuzz" (noise?).

Do I need a filter? If so, would it come before or after the WBFM 
Receive PLL block?

Once I have a good design, I will use it as an Example Flowgraph.

Thanks for your help.
--
Barry Duggan KV4FV