rant invalid. State v. Boniface, 26 Ariz. App. 118, 546 P.2d 843 (1976). The failure to execute any writing before the search invalidates a telephonic search warrant. Bowyer v. Superior Court, 37 Cal.App.3d 151, 111 Cal.Rptr. 628 (1974), reh. den. 37 Cal.App.3d 151, 112 Cal.Rptr. 266.
A close reading of the cases decided under these provisions indicates that the violations which occurred relating to the search of appellant’s residence were technical in nature and do not render the warrant invalid. The key element in the issuance of a telephonic warrant, like any other warrant, is consideration of the affidavit by a neutral and detached magistrate. Yuma County Attorney v. McGuire, supra. It would be a different case if there was proof otherwise, but here it is clear that the magistrate heard testimony from Agent Chaboya under oath upon which he based his finding of probable cause. As in State v. Smith, supra, there is no hint of intentional misconduct or bad faith on the part of the prosecution. The California Court of Appeals, faced with a similar question, stated that a literal compliance with the statutory provisions is preferable, as it removes all doubt. People v. Chavez, 27 Cal.App.3d 883, 104 Cal.Rptr. 247 (1972). In light of the potential for abuse, it is especially important that the judiciary and law enforcement officials comply strictly with the statutory guidelines for telephonic search warrants. Under the facts of this case, however, substantial compliance rather than literal compliance does not void the warrant. As in Chavez, this is particularly so in view of appellant’s failure to demonstrate prejudicial error resulting from the procedural irregularity.
TAPE RECORDING
Appellant next questions the propriety of the trial judge’s actions at the suppression hearing. Faced with the question of the accuracy of the telephonic affidavit transcription, the judge took possession of the tape, which had not yet been admitted into evidence, listened to it and found that the transcription was “accurate in all material respects.” After objection by appellant, the judge allowed the state to reopen its case for the purpose of offering the tape into evidence, and admitted the tape in evidence. Appellant contends that consideration of matters not in evidence jeopardized the role of the judge as an impartial fact finder and violated his due process rights.
The cases appellant cites to support his argument deal with jurors receiving and considering evidence not admitted at trial. Rule 24.1(c)(3)(i), Arizona Rules of Criminal Procedure, relied on by appellant, specifically refers only to jurors. In a court hearing, a liberal practice in the admission of evidence is followed supported with a presumption on appeal that the judge below, knowing the applicable rules of evidence, will not consider matters which are inadmissible when making his findings. State v. Miles, 77 Wash.2d 593, 464 P.2d 723 (1970). The judge at the suppression hearing properly considered the tape recording, and was within his discretion in allowing the state to reopen its case to offer the tape into evidence. Rule 104(a), Arizona Rules of Evidence (preliminary questions of admissibility are to be decided by the court); State v. Riggins, 111 Ariz. 281, 528 P.2d 625 (1974). In any event, the judge was seeking the truth and there has been no showing that appellant was prejudiced by the use of the tape recording, requiring a new trial. State v. Turrentine, 122 Ariz. 39, 592 P.2d 1305 (App.1979).
PROBABLE CAUSE
Appellant attacks the magistrate’s finding of probable cause on two grounds: First, that alleged misrepresentations contained in Agent Chaboya’s affidavit vitiate the warrant and require that all items seized be suppressed, and second, that all information received pursuant to the informant’s tip must be suppressed because the requirements of Aguilar v. Texas, 378 U.S. 108, 84 S.Ct. 1509, 12 L.Ed.2d 723 (1964), were not met. We find that neither of these contentions have merit.
Agent Chaboya’s affidavit contained three statements allegedly made by Gart-