Dear @rpmpam : There is no problem with the preamp, the problem is between the Dartzeel amp and the MBL speakers because the 101 E has a very low sensitivity at 81db and dificult impedance phase at 3.3 ohm.
Those speakers needs at least the Dartzeel NHB 468, nothing less if you want Dartzeel or if you already own the 108MK2 then a diferent speaker choice.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.