
KTD power amplifier
1918
1918
1922
circa 1920s-1930s
1930
1924
1923
1923
1927
1932
1927
1925
1943
1932
1923
1932
1923
1925
1925
1925
1925
1925
1942
1928
1923
1928
1924
circa 1923
1927
1935
1925
circa 1930
1931
1940
1923
1923
1923
1928
circa 1920
1918
1925