Here the complete answer from Kanoko Yamada after the permission to publish it here:
The founder of Zanden Mr. Kazutoshi Yamada added "AP (coda) MR" to Zanden logo and hoped that “Audio Product” and “Music Recording” would end up in Zanden.
As you know, coda is a symbol used in musical score and means the end.
He hoped to someday make the best final form, both in terms of audio products and music recordings.
And now, Zanden continues to make products to reproduce the recorded sound as it is, while respecting the recorded music.