Antique Vintage Koch Harmonica
Antique vintage Koch harmonicas are few and far between even on ebay. Last time I looked there were only a handful of auctions available. The Koch chromatic was an inexpensive harmonica from Hohner which took over Koch to eliminate the competition.
Used antique Koch chromatics can sell for about $15.00 used with no box to around $100 in good condition with the original box. A new one sells for about $80.00. Here are a few listings available now.
Vintage Koch Harmonicas
Antique Hohner Harmonicas

Matthias Hohner, was originally a clockmaker. He started making harmonicas by hand in 1857. There were 650 made in the first year. Hohner harmonicas quickly became popular and during Matthias' lifetime and he built the largest harmonica factory in the world. During the American Civil War, Matthias Hohner gave harmonicas to family members in the United States who in turn gave them to the fighting soldiers.
These listings are for Antique Hohner Harmonicas available at live auctions now. Bid early to get that treasure you have been looking for.
Antique Hohner Harmonicas Available Online Now.
In the 1920s Hohner began manufacturing chromatic harmonicas that can be played in any key. In the mid 1950's Hohner began producing electric guitars. In 1964 Hohner released The Beatles Harmonica Kit which was sold in a blister package, much like most Hohner harmonicas nowadays, retailed for $2.95, and help what Hohner calls "bring about a new popularity upsurge of the Hohner harmonica on both sides of the Atlantic.". In the 1970s Hohner began manufacturing acoustic guitars, and re-producing electric guitars. Read more about Hohner harmonicas online at wikipedia