si.edu21 天
Pullman Palace Car Company Collection
Creator: Pullman Palace Car Co.Pullman, George M., 1831-1897Names: Lincoln, Robert Todd ...
si.edu12 天
Kennedy type 521 two-stage radio amplifier
Marked: "Type 521 / Two Stage Amplifier / The Colin B. Kennedy Co. / San Francisco / Saint Louis"; on metal tag: "Serial No. L5038W6". A two-stage audio amplifier using two 301-A triodes with a ...