I do not understand what you mean with "to host PPC ROM". Do you mean you want to run the PPC version of Tiger?
PearPC can run Tiger, but I assume you are go to run it on a Mac. If correct, PearPC will be extremely slow. The version we provide cannot have the acceleration features available on Windows/Linux. And it is rather old. Besides that, PearPC is not very stable.
So that leaves you with the Qemu option only. Qemu runs on the following hosts: Mac OS X El Capitan and above, on Windows 7 and above and on Linux. It provides emulation of a PPC based computer on which you can run PPC Mac OS 9.x up to 10.5.
You can find downloads for the most recent version of Qemu running on OSX here: viewtopic.php?f=34&t=8848&p=52102#p52102
Here is also a link to the guide we provide:https://www.emaculation.com/doku.php/pp ... mu-for-osx
If you don't have a PPC Tiger DVD available, search the macintoshgarden website for a suitable DVD image (Tiger_4_6.dmg_.zip) to install Tiger.
You say you do not need support for CD/DVD, a network, USB, or printer. How are you going to get files in and out of the emulated PPC Tiger environment to do your conversions?
Getting files in and out of Tiger is easier when you run our Qemu version for OSX hosts.