audionews.org is a great private tracker, I've downloaded terabytes worth of stuff from there.
There's open registration to the public on the second of every month and you need to keep a seed ration of above 0.8 to use it properly though or donate money. Just find newer torrents that have lots of leaches and seed it, after a dozen or so you'll have a decent ratio and can download whatever you want.
You'll need to configure your torrent program to specifically use that site though so I'd recommend getting a second torrent program used just for that tracker, if you're not used to private trackers it's a bit of work to set up properly compared to the one click method of using public trackers.
The thing I like the most about the site is the troubleshooting in the torrent threads that is involved for pirated music production software.