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Dating mullard valves

Fleming's patents for the very first electronic valve. The manufacturer is important as well as the valve type, since valves with the same type number from different manufacturers may vary significantly. These books all contain full page sheets on each valve covered with at least one curve for each valve.

I have made a full table of manufacturer recommended substitutions with links to PDF data sheets, where available. The complete index has an ordered table of all the valves covered in these books with links to their data sheets as full page PDF files.

Each book also has short data on some obsolescent types, circuits, articles on construction and lists of valve sets for commercial radios and kits.

The This Cossor manual has interesting articles on: valve fundamentals; valve construction and valve types as well as full page descriptions with curves of sixty valve types.

Heater and cathode life was poor and good working specimens are uncommon.

I know this has been discussed here before, but I've misplaced my hard copy of how to decipher this. In the case of the 1st letter, ie 'B' for xf2 that's the factory code, xf1=Blackburn, xf2=Blackburn -or- Eindhoven, Holland.

There are acorns, nuvistors, electrometer tubes, barreters, time delay relays and laboratory and test samples. A timeline of the development of valves and broadcasting in the U. A history of Mullard with some pointers on dating the PM series valves. Some compilations have been found to be unreliable, particularly about equivalences.Valves used by the British military Armed Services were marked with a CV or common valve name which was defined by the Inter-Service Technical Valve Committee in 1941.Often, below the CV number, a two part alpha code of the form KB/xx or JB/xx will be seen which gives the devices manufacturing specification and qualification .A fairly large selection ( The gallery of optoelectronics contains all the vacuum and gas-filled valves used for display or light detection.Included are tuning indicators, photocells, flash tubes, a vidicon and a photomultiplier. Howe on the fiftieth anniversary of Fleming's invention of the first electronic valve.

In a separate cartouche there often is a two character alpha code which denotes manufacture date eg AA.

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I have just received an e-mail asking for details of military valve markings so here's a little primer for anyone who might have a similar interest. Valves used 
02-Jul-2018 04:44
Mullard nomenclature - Mullard AC Mains Valves. The AC044 in the photo is a genuine Mullard-made specimen, dating. Early specimens of the redesigned Mullard. 
02-Jul-2018 04:47
A history of Mullard with some pointers on dating the PM series valves. The Mullard Rapid Valve Guide and the 1933-4 Mullard Master Valve Guide were kindly. 
02-Jul-2018 04:52
There is another system of date marking used from about 1965 onwards and that consisted of four digits, the first two being the year and the last two being the week so 6407 would be February 1964. The date code was the date the code was put on the valve so if there may be an earlier manufacturers code on the valve as. 
02-Jul-2018 04:55
No dating method can ever. 1922-1925 - valves had metal British 4 or 5 pin bases and a "pip" on the. Philips and Mullard introduced the first of their. 
02-Jul-2018 05:00
Capt. Stanley R. Mullard, founded the Mullard Radio Valve Company Ltd. in 1920 and it became a premier manufacturer of electronic components. 
02-Jul-2018 05:05
Vintage Mullard 12AX7 made in the 1960's and 1970's have great accentuated midrange tone and bass, and are an overall excellent 12AX7 choice for Hifi and guitar amps! 
02-Jul-2018 05:10
Mullard EL34 production codes. This was a post on an amp BBS asking about Mullard EL34 production codes, what they mean, and my response I know this has been discussed here before, but I've misplaced my hard copy of how to decipher this. 
02-Jul-2018 05:13
The SD20 and Pen20 valves are Mullard versions of Philips-designed originals dating from the early 1930s. They might even be imported although all BVA valves were supposed to be British Made. 
02-Jul-2018 05:18

Dating mullard valves introduction

Dating mullard valves

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