Here are a few of the many Chinese harmonica companies
that may have made your North Star tremolo harp. You
have written that it's a Koch harmonica, made by Hohner.
The most popular harmonica companies have, at one time
or another, sub-contracted smaller companies to make
their less expensive harmonicas for world distribution.
For example, Hohner, Hering, Huang, Seydel, Suzuki,
Tombo, have all sub-contracted Chinese harmonica
These are the most famous Chinese companies, and their
web and/or email addresses. You may search freely with
these companies. I don't think that Easttop, maker of Bee
harmonicas, manufactures the North Star harps for Hohner:
Jiangsu Swan Musical Instrument Corporation ("Swan", founded 1982):
Wuxi-Suzuki Musical Instrument Company, Ltd. (a collaboration
between the Chinese Wuxi and Japanese Suzuki companies,
founded after 1992; "Golden Butterfly" and "Wuxi" brands):
(a distributor, not the manufacturer)
Jiangsu East Musical Instrument Company ("Easttop" and "Bee"
brands, founding date 1997):
Check the companies' websites for illustrated products.
Some of the above addresses may be expired.
At a recent Frankfurt, Germany, Products Trade Fair (circa 2008?),
there were 53 Chinese harmonica companies listed in the
exhibitors' roster. It's difficult to find them all.
Also, Hohner is currently owned by KHS Musical Company, Ltd.,
of Taipei, Taiwan. Major harmonica companies rarely publish the
names of their sub-contractors:
(USA Hohner distributor)
Good luck in your search.