How to make a push-pull transformer for a low frequency amplifier

Author: Ryszard Zarzecki
Radioamator i Krótkofalowiec, Rok 19, Sierpień 1969r., Nr 8
(Radio amateur, Year 19, August 1969, No. 8)

   When designing push-pull amplifiers, it is often difficult to acquire or manufacture a suitable output transformer. The Soviet monthly "Radio" no. 2/1967 presents a simple method of making such a transformer. For this purpose, two identical, "normal" output transformers are needed (for example from a "Pionier" type receiver). Metal clamps and a package of simple plates closing the core should be removed from these transformers, and plates of the "E" type should be left together with the bodies with windings placed on them.

   Transformer cores with windings should be put together as shown in Fig. 1.

Fig. 1.

In this way, the assembled transformers are connected and squeezed with a new metal clamp, and then - the beginning of the anode winding of one transformer is connected to the end of the anode winding of the other transformer (Fig. 2).

Fig. 2.

The secondary windings can be used individually from any transformer, or both connected in series, like the anode windings.

Provided by Grzegorz 'gsmok' Makarewicz