The deep stall is a combination of T-tail and rear mounted engines. The wing effectively blankets the engines and tailplane/elevator when high AOA are achieved as in a stall. Thus the engines also stall/surge and therefore the a/c cannot power out of the stall plus the elevator/tailplane become ineffective due to the disturbed airflow created by the wing.
Having said that, the combination of a very clean wing and all the noise at the back gives a very comfortable ride for the First class punters up front. The VC10 is a good example.