Roehrencodex refer Ultron to Mazda (France ?). I have a Ultron 4A15 with box. The box does not refer to a manufacturer. On the glass of the tube is the text: Licence SEM-SBR, which means that this tube was sold in Belgium. A Philips Roehren-Vergleichungslist from Januar 1939 shows that the Ultron  brand was used up to 1940. All considering, it looks likely that Ultron was a Mazda brand.

Attachments

• Ultron Veregleichingslist (154 KB)

Peter,

A few days ago I acquired a radio of the Belgian brand RGM (= Radio Geerts Mechelen). It is a prewar AC model and is equipped with 5 Ultron tubes: 4A17, 4A16, 4A22, 4A24 and 4R3. Maybe this helps in answering the question what the origin of the Ultron tubes is.

I will upload the pictures to the tube pages.

Gidi

Attachments

• Ultron tubes (61 KB)

Before WWII the “Ultron” brand name has belonged to the “Manufacture Belge de Lampes Électroniqiues”, or in short “MBLE”.

MBLE used the brand name “Ultron” for European type tubes, for American type tubes they used the brand name “Adzam”, as well they used the brand name “Mazda” for lighting bulbs.

Apparently, after WWII they dropped the “Ultron” brand and henceforth they used the brand name “Adzam” for any tubes.

Later on, the German electronic distributor Bürklin took the brand name “Ultron” for the tubes they sold as reseller.

Regards, Jacob

Attachments

• MBLE_Manuel_Tubes_Adzam_Ultron_3marques (111 KB)
• MBLE_Manuel_Tubes_Adzam_Ultron_intro (212 KB)
• MBLE_Manuel_Tubes_Adzam_Ultron_titel (8 KB)