and I now have what looks like sine wave audio output.
so I added an RC network ( 3 x 1.5K resistors & 3 0.01uf caps )
except when the 10k volume pot is roughly mid position there is some un-distorted playback but very quiet.
My scope showed that the Uno output is a square wave
The Dc blocking Cap is next to spk output and is 250uf.
If the volume pot is moved away from the narrow band when sound can be heard, it doesn't get louder or softer, it just goes off .. .. must be something to do with those voltages I think, they look bizarre to me. !!