I have got some info about PA system used here in Spain at their gigs in Madrid & Barcelona in July 1965, as well as the company which provided the backline. I will let you know...
Casa Alberdi, from Barcelona and distributors of Vox gear in Spain, provided the PA system as well as the amps for the other acts (=I mean, non-Beatles one) both in Madrid and Barcelona:
For Alberdi this was a very good chance to display that they were selling same gear as the one used by The Beatles:
According to the agreement, signed by NEMS and Francisco Bermúdez (=ruler of the Spanish Management Agency who brought The Beatles to Spain) and dated 5 February 1965: "...It is agreed that you provide first class dressing room accomodation and a first class public address system with at least 3 microphones..."
You can see the Vox amps privided by Alberdi to the other groups, behind McCartney at this photo (=from Barcelona's gig):
The agreement also specifies accomodation and transport inside Spain for at least 9 people.
John, Paul, George, Ringo, Brian, Mal, Neil??, Alf Bicknell and Wendy Hanson...