Compatibility of 26 ohm output with -10dBV jacks on a mixer?

I use the stereo outs into a Yamaha 12 mixer (stereo L/R -10dBV jacks) while 26 ohms seems in the order of things (like low headphone impedance) it also seems, as with the range of performance with headphones, that I quickly hit a max limit. I’d hate to have to take up two ‘more flexible’ channels (meaning I now need to buy a 16 channel board).

I could (grudgingly) preamp the signal with another currently unused 8 channel board and feed that into the main board.