M-8137 box plates made by Mullard > branded Telefunken with their logo ECC803S.
This valve was supplied to the Dutch Bang and Olufsen service centre.
When Telefunken of Western Germany closed their production factories they still had a demand for their ECC803S audio tubes. Where better to source an alternative than Siemens & Halske Germany or Brimar, Mullard in the U.K.? And from Mullard they chose the best, the famous box plate M8137; one of the finest ECC83. Telefunken ordered a very limited supply of these beauties for this Telefunken non-diamond bottom ECC803S. To comply the very strict specification of the ECC803S, Telefunken has undoubtedly used selected versions of the M8137 only.
The acid code 641 R9B1 code on the glass indicates that the tube was manufactured in februari 1969 in the Mullard plant in Mitchum. The tube has box plates and a round halo getter. The tube has excellent test values that match the factory specification very well and balanced systems.
(Telefunken factory specification see last picture)
- Tube code: ECC803S
- Actual Brand*: Mullard
- Printed Brand: Telefunken
- Manufactured in: UK Mitchum plant
- Visible Date Code: 641 R9B1
- Production date: first week februari 1969
- Plate Construction: box plate
- Getter Construction: round halo getter
- Print Condition: new; see picture
- Box included: replica (see picture)
- Equivalent tubes: CV4004, 12AX7, ECC83
- General test results: NOS
- Quantity of Tubes: 1
“Mullard Limited” was a British manufacturer of electronic components. The “Mullard Radio Valve Co. Ltd.” of Southfields, London, was founded in 1920 by Captain Stanley R. Mullard, who had previously designed valves for the Admiralty before becoming managing director of the Z Electric Lamp Co. In 1924 he raised capital by selling half the company to “Philips” of the Netherlands, who bought the rest of the company in 1927.
Telefunken specification NOS ECC803S