I use the Grado with Senn HD600...the combo is fine. The direct out from my CD is good, but your's may be higher voltage...check with Linn.
If you hook it to the tape monitor, you should be able to turn down the volume on the preamp...it should bypass the volume control.
If you hook it to the tape monitor, you should be able to turn down the volume on the preamp...it should bypass the volume control.