Marconi, Marconiphone etc.:
To avoid the existing mess in the literature (there are different, contradicting manuf.names given for the same model!), here are all Marconi products concentrated, regardles whether they were made under the name Marconi, Marconiphone, Marconi Wireless, Marconi Scientific Instruments, and so on.

The Wireless Telegraph and Signal Company became Marconi Company near the end of the 19th century. A Department of this Society (Marconiphone) produced domestic equipments from 1920 and was sold to the HMV in 1929. The HMV became part of Columbia Gramophone Company that acquired therefore the right to use the Marconiphone brand and the logo G.Marconi. The Gramophone Company became EMI from 1931 to 1956 and then became part of the THORN group. Therefore all the production between 1929 and 1979 has nothing to do with the Marconi Company. In 1979 the Marconi Company bought back the marks Marconiphone and G.Marconi.

(Marconi; GB: Vertretung Schweiz: Hug & Co.; Basel + Zürich: - siehe auch His Master's Voice. Lautsprecher GV = Telion SA; Lausanne [3331451]. Thali bringt die Marken HMV und Marconi etwas durcheinander. Hier ist diese Einteilung dennoch belassen, damit Sie ein Schema wirklich finden.)

Initially Marconi Scientific Instruments, Soho, started to make receivers for the amateur market, but in 1922 the "Marconiphone" department was set up at Chelmsford. in 1925 it became "Marconiphone Co.Ltd.",who moved their headquarters to Sterling´s premises at Tottenham court Rd. Production was then mainly at Dagenham. Altogether there were about 1500 of Marconis Associated Companies!
Ref.: Geddes/Bussey, "The Setmakers".

Marconi Co. never produced Valves/Tubes: - see Marconi-Osram.
See Tyne, "Saga of the Vacuum Tube", page 372: "It cannot be emphasized too strongly that despite the markings on valves used by them, Marconi Co. never made valves." Here some details:
Until 1919 Edison Swan Electric Co. Ltd. (Brand Ediswan) produces mainly for Marconi. In 1919 Marconi and GEC are founding the Marconi-Osram Valve Co. Ltd. This company does not produce valves but does the engineering and designing.

From 1928 Ediswan, BTH and Metrovick join their activities in valves (tubes) and form the "Associated Electrical Industries (AEI) but Ediswan does the production for all three companies. In 1960 AEI and Thorn Electrical Industries Ltd. form the Thorn-AEI Radio Valves & Tubes Ltd. and by that the brand Brimar is merged too.
Ref.: "Radios von gestern", pages 215, 216.