I used to use my Carvin PB500 to run 4 monitors before with no problem some years back.
My R600 is even more powerful.
I just bought it on ebay and it worked, but was super quiet! There was a little rattle when I moved it too.
I took it apart and the preamp tube was just lying in the cavity! The silicon that held it in place had dried out apparently. I plugged it back in and it was immediately loud as sin once more! Can barely get it past 2-3.
So I put a little liquid nails in there to hold it, and now it works amazing.
I'm running it bridged mono through an old Acoustic cab with two 15" JBLs in it. Sounds great.