Hi there, I have recently found a very small Amplion crystal receiver, it still has its box and says 'any time is melody time' I wonder if anybody could tell me anything about it??

You might try contacting the owner of this website: (Click on the link)
The SparkMuseum!
He seems to be quite knowledgeable about receivers of the crystal era.

I believe Amplion was a British brand. There is a UK-based antique radio forum that could be a place to post your question. I don't have the URL, but you could Google for it.

Most crystal radios are so simple they are their own schematic.