I'm using the latest version of Platinum.  It seems only lately I can't get the CA Compressor to work in the side-chain mode.  I'm doing exactly as I've done for a few years now but it's not reacting.  My example:  I have a guitar solo at the end of the song.  The vocalist is singing as well.  I put the CA Compressor on the guitar and trigger it with the vocal- by inserting a send on the vocal to feed input 2 of the CA Compressor on the solo guitar track.  I verify that the side-chain is turned on on the compressor.  Nothing.  When I turn off side chain the compressor is working. 

of course what I'm wanting to accomplish is while the singer is still singing the compressor lowers the guitar and when she stops it takes over. 

Thanks in advance.

Personally I would automate this for more control. I don't think side chaining in general is broken although I haven't checked with the CA2A (assuming that's the one you mean).

Sure I could automate it.  However, I've found the CA2A (yes, that's what I meant) works nicely for the task.  Just checking because it has worked for a few years now- and doesn't at the moment for me.

it seems to be unique to the CA2A compressor.  The Buss compressor works in side chain.  I guess I'll figure it out.

It seems to be working for me using a simple side-chain test I use sometimes. 
 
I tried the pro-channel version and the VST3 plugin version of the CA-2A compressor.  Use the drop down to enable the external side-chain, add a send on the vocal track to the side-chain input (exactly what you described).  Then I turn the peak reduction up 100% (just for testing).  The background track gets compressed when the foreground comes in (in my case spoken dialog over a background ambient sound effects track).

I can confirm that it is working.

thanks.  maybe it's unique to the project I'm working on. 

I can't get Melda's MDynamicEq's external side chain to work in SPlat.  Same symptoms.  Other plugins I've tried work though, including the CA-2A.
 
http://forum.cakewalk.com...ain-Help-m3427046.aspx

Side chaining that MDynamicEq plugin works fine in another project.  Who knows.