I'm in a small trio and my vocalist just bought a Mackie SRM150 to use as a monitor for gigs. I'm certain the unit will work great when she actually uses it.
She also wants to practice with it and use headphones to hear her voice better. I noticed there was no headphone out. We tried to use the thru with various adaptors to hookup headphones but it didn't work.
Will something like the Ross MX28 work with the Mackie so she can use headphones?
What you want is a headphone amp. Take a line level signal from the "thru" jack to the headphone amp. A.R.T. makes a good one, as do several other companies.