This happens in any VST host I try, except -- AudioMulch by Ross Benicia. In AudioMulch I can build a preset stack of multiple XTC and native plugins, tweak, and mixdown. Finally, just as advertised!

But I shouldn't have to do this extra step. Probably I have something set wrong in VST and Nuendo. I am running Pent4 1.7 GHz, 256MB RIMMs, Win98, and a Gina 20 with latest driver. Hosts are set to use the Gina ASIO driver, not the generic multimedia one. Master audio device is the SPDIF, and the 1/2, 3/4, 5/6, 7/8 pairs are Buses 1-4. I distribute my tracks across the analog outputs (no external DA converter).
In mixing down I have tried many combinations of bus settings. It doesn't seem to matter what device(s) I choose, when mixing down in VST or Nuendo I can only get silence. I know I'm missing something but just can't figure out what it is...
I've searched the boards for terms like "XTC empty tracks" etc but not much luck. I will keep searching but wanted of course to ask the nice folks at PlanetZ.
I don't think this is a 3.1 vs. 3.0 problem at all because AudioMulch works fine.
Best,
h23