[David Haggett]
Hmm.  It did indeed build fine, and the plugins are all available.  I'm seeing
an oddness with the AmpVTS interface in Ardour however:
The "model" selector is numeric 0 to 5, which is what I expected, but the gain
control is a dropdown-list showing the names of the models.  Anything above
"'64 Princeton" is unusable because of oversaturation. 
That's a bug in the RDF file, the port number doesn't match.  Thanks for
reporting it.
The patch (straight this time, no -p1) is attached to this mail,
also available here in case the file doesn't survive being mailed to
this list:
http://quitte.de/dsp/caps/caps_rdf_AmpVTS_model.diff
 I also checked the "ToneStack" plugin in
ardour, and that provides a text
representation of the model, which is I guess what should happen in AmpVTS
Jack-Rack displays the AmpVTS controls as expected - gain is a slider going
from 0 to 3, so the problem is specific to ardour.   
jack-rack ignores the RDF, that's the reason.
Thanks, Tim