From the 2002 General Instruction of the Roman Missal (GIRM) approved for the USA, which can be accessed from
romanrite.com/girm.html :
“306. Only what is required for the celebration of the Mass may be placed on the mensa of the altar: namely, from the beginning of the celebration until the proclamation of the Gospel, the Book of the Gospels; then from the Presentation of the Gifts until the purification of the vessels, the chalice with the paten, a ciborium if necessary, and, finally, the corporal, the purificator, the pall, and the Missal.
In addition, microphones that may be needed to amplify the priest’s voice should be arranged discreetly.” (My bold text.)