Mr Mackellar sent my question to Mr Lindsay.
He could also confirm that the photo did not depict a 9120. Which I could have known, but somehow I didn't see that the caption said "Gemini" instead of "Apollo"...

I'm curious whether Mr Lindsay can give any information on the 9120!

The Marantz company hasn't replied yet, but the contact person just returned from a holiday so he probably has a lot of mail to go through.

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.