David Looser wrote:

A complementary pair of transistors, as suggested, would have a bandwidth
plenty wide enough for video! But the linearity would leave rather a lot to
be desired, more crossover distortion than the LM324 probably. But I wonder
if Tony L has read the data sheet for the LM324?, it clearly states that
with an AC coupled load (I assume he has capacitively coupled his
headphones?) a resistor should be connected from the output pin to ground
"to avoid crossover distortion", has he done that?

The LM324 is a piece of crap in the first place ! It has an intentional near
dead-band.

Graham