[G6Tanuki]

The S27 outpuut-transformer also includes a feedback-winding for the tone control.

In the past I recall a trick to avoid replacing the output-transformer in radios with P-P output but only 'high impedance' secondaries on the transformer.

You get a normal single-ended-output-transformer and wire its primary between the two anodes of the P-P stage.

The original P-P transformer then acts, essentially, as a 'centre-tapped choke'. This works well with even a rather small single-ended output-transformer, since it's not having to pass any DC.