The same problem with the DC flow in the
transformer exists when a power transformer
is used with a halfwave rectifier.
Typically the transformer rating is degraded by
60% when be using with halfwave rectication
due to the DC current flowing in the secondary.

Many folks have used filament transformers
as audio outputs replacements with good results.
The transformer rating is decreased by the
standing DC current, but it will
still handle a good amount of audio before
saturation on peaks occurs.

Peter