Edward Moogk in Roll Back The Years (National Library of Canada, 1975) pg 118 says:

"The piano industry was also dealt a sever blow during the decade [the 1920s]...The Karn Piano Company of Woodstock, one of the oldest manufacturers in Canada, was purchased by Sherlock-Manning, and the Karn player lines continued."

Betty Pratt's Star article in May-Jun 2008 Antique Phonograph News also states:

"Gourlay, Winter & Leeming Pianos, based in Toronto ... They were also dealers in cabinet organs, made by ... Karn (Woodstock)..."

Betty also sent this link from the Woodstock Museum (http://www.woodstockmuseum.ca/documents.php?file=b5a1d925221b37e2e399f7b319038ba0) which contains:

Karn Organ and Piano Company
J. M. Miller and Dennis W. Karn formed a partnership to manufacture musical instruments in 1867, know as Miller and Karn. Dennis W. Karn was mayor of Woodstock from 1889 1890, and a survivor of the St. George Railway Disaster of 1889.
This partnership was dissolved in 1870 and the factory became known as D.W. Karn. The first factory was located on the southwest corner of Dundas and Reeve Street. The factory was moved to the south side of Dundas Street, just west of Wellington Street but was destroyed by fire in 1879. The factory was rebuilt on the same site but this too was destroyed by fire in 1886. After this fire, the old Woodstock Hotel, a four-storey white brick building was acquired at the corner of Dundas and Wilson to be fitted for the piano branch of the factory. A large building immediately across the street at the corner of Dundas and Wilson was also acquired. This company began to make pianos after 1886; the first Karn player piano was built in 1901.
In 1896, S.R. Warren and Son Organ Company of Toronto bought out Karn and it began to build Karn-Warren pipe organs. In 1901 Dennis Karn retired and the company amalgamated with the Morris Piano Makers of Listowel to form Karn, Morris Piano and Organ Co. Ltd., with E.C. Thornton as general manager. In 1902 the Karn Morris partnership was dissolved. In 1924, the company was purchase by Sherlock-Manning. Between 1923 and 1935, a group of former employees operated the Woodstock Pipe Organ company in the building on the corner of Wilson and Dundas Streets until 1955. Over 75 styles of the world famous Karn Organ were made here over the run of the business.

Bob Nix found this plate in a shipment of phonograph cases, June 2009:

Betty Pratt found a Karn advert  Sept. 1923,p. 10, Vol. 24, No.4, in Canadian Music Trades Journal (detail--edited by KW):

Sept. 2011, Ed Kraushar of Campbellford, Ontario gave me permission to use the following pictures of his machine (No. 1744):




Karn 'trade cards' from Downright Upright, A History of the Canadian Piano Industry, by Wayne Kelly, Natural Heritage/Natural History Inc., 1991, pg. 31:

Quebec Telegraph Sep 21 1921 pg 19:

Machine for sale March 2014.  Note the hinged motor board and the reproducer that swivels for lateral or hill-and-dale records:


Online sale April 2014: