I have had the price list for some time, Bruno. The brochure shows the Microphone pickups for the Professional 36 and the Basso. These pickups were announced in 1964, so those two models were already on the market. And your 1962 photo shows what appears to be the Hohner Professional 36. The first piano key Hohners were introduced in 1961, and these were heavily advertised. We know now that Hohner was also more quietly at work on a melodica for professionals. Hohner’s big melodica advertising campaign during the 1960s did not give much attention to the higher end models. I have been researching the ads and announcements.
You may have to travel to China to find out what’s really going on.
I have a recent Piano 26 apart and its reeds and reed plate also have gray oxide. It’s sad if the quality of the reeds was sacrificed in the more recent versions. There’s also very little evidence of factory tuning on this particular Piano 26.
Further evidence that at least some vintage models may have better sound than more recent versions.