Does a preliminary hearing need to be held where a parolee has been revoked on the basis of a parole violation charge?

Morrissey indicates that no preliminary hearing is required where parole is revoked on the basis of parole violation charges admitted by the parolee to the parole board. (408 U.S. at pp. 477, 490, 92 S.Ct. 2593, 33 L.Ed.2d at pp. 492, 499; see also, People v. Vickers, supra, 8 Cal.2d at p. 457, 105 Cal.Rptr. 305, 503 P.2d 1313, fn. 6.) However, petitioner's entitlement to a preliminary hearing on all charges--including the allegation of a new conviction--was in no way lessened by his subsequent admission to this court that he in fact pleaded guilty to drunk driving on September 14, 1972. Absent any showing that petitioner has admitted the charges to the parole board, the denial of a preliminary hearing has deprived him of due process.