The QQV03-25 is an enhanced version of the QQV02-20A double beam RF power tetrode. The maximum dissipation per anode is raised to 12.5 Watts by the addition of an extra U shaped fin.
The QQV03-20A makes a very acceptable audio power amplifier. The sound is smooth and mellow but the output power is about 3 Watts when driven as class A push-pull.
The central tower has the common beam plates, common screen grid and common cathode. The two control grids are placed very close to the flat rectangular section coated cathode tube with one on each side.
Looking into one of the anodes with the central additional fin.
A close-up of one anode.
The wide glass tube envelope is 44 mm in diameter, and excluding the base pins is 52 mm tall.
Reference: Data-sheet. Type QQV03-25 was first introduced in 1964. See also1964 adverts.