Philips had factories everywhere.
Holland made tubes, were branded as Philips, Philips Miniwatt, Amperex, Dario, RT, Mazda...and having the triangle sign etched at bottom of tube, including tube type and manufacturing dates, noted that they were manufactured at Heerlen factory in Holland. All were the same tube, having the SQ logo or not. In fact some Holland made ones, were branded Amperex, had the PQ logo, that was used for the ones made in USA and having the * sign etched instead.
India made tubes under licence for Mullard, BEL factory same tooling, different etched codes.
So to be sure always check what the etched codes are for finding out which factory they were coming from.
Holland made tubes, were branded as Philips, Philips Miniwatt, Amperex, Dario, RT, Mazda...and having the triangle sign etched at bottom of tube, including tube type and manufacturing dates, noted that they were manufactured at Heerlen factory in Holland. All were the same tube, having the SQ logo or not. In fact some Holland made ones, were branded Amperex, had the PQ logo, that was used for the ones made in USA and having the * sign etched instead.
India made tubes under licence for Mullard, BEL factory same tooling, different etched codes.
So to be sure always check what the etched codes are for finding out which factory they were coming from.