DSP LADSPA audio plugins, DSP utilities and investigations.

caps is the collection offering improvements over all previous efforts released here, and then some.

the pvoc collection has more LADSPA units and a time-stretching utility.

a valve-emulating preamp model, version 2.

unmatched and matched also do 'cheap' amp/cabinet emulation.

an older spiced 12AX7 analysis and a simple hard clipper.

There are RPMs of the older plugins available too, prepared by Adrian Likins: http://people.redhat.com/alikins/repo/RPMS/.

You may want to read the GPL.