Diva, Zebra2, Zebralette, Hive and Podolski running with only minimal crackles and glitches.
Thanks to all the good people which give me advices and suggestions. I think it was simple a graphic issue of the U-He plugins which is solved.
BTW I've purchased Renoise Redux today, so now there is a very promising sampler VST available for Linux. Redux can use SFZ as multi sample and xrni from renoise sampler. There are issues but it looks good and stable. With the ability to render VSTs (via Renoise Sampler) I can export a nice growing sample library for my Linux playground from my Mac.
http://www.renoise.com/redux
