I need some advice re: real-time stereo pitch shifting

hello y’all…  I am looking to buy a 2nd-hand hardware box that will allow me to input a stereo analog audio signal and get a clean pitch-shifted polyphonic octave-down.   I’ve been looking at eventide H3000s on eBay but they are just a bit too expensive for what may be a total boondoggle.

I don’t need uber-fidelity; 44.k sampling rate and 16-bit internal processing is fine.  Balanced i/o would be very good but maybe not a necessity?

And pls no speculation or armchair recommendations folks; I am just looking for suggestions from people who have actually used the suggested device personally for this specific task.  Thanks for reading – c.