Using a headphone amp as a line preamp should present no problems and could make the circuit work better anyway. Since the load impedance of the headphone is removed for use as a line stage it’s circuit should then work with lower distortion.
For poweramps, try the classic Music Reference RM-10. It’s a powerful little push pull EL84 poweramp offering around 35w, that should drive 89dB speakers to reasonable levels.
For poweramps, try the classic Music Reference RM-10. It’s a powerful little push pull EL84 poweramp offering around 35w, that should drive 89dB speakers to reasonable levels.