THE GREAT MULLARD MAGIC BLOG

GLASS ENGINEERING FOR CATHODE RAY TUBE MANUFACTURE (i)

Posted by STEVE MYCIUNKA on

GLASS ENGINEERING FOR CATHODE RAY TUBE MANUFACTURE (i)

In the very early days of television, the bulbs for cathode ray tubes (CRT) were blown by hand, however, due to volume requirements, most CRT bulbs were moulded, being made in two parts with the flattened end termed the face-plateand the pear shaped body termed the cone.  As the separate parts were delivered to the Mullard factory, at this stage in the early 1950s that means the Blackburn works, the first stage after inspection for blemishes was to join the parts.  Any components marred by blemishing were returned to the glass moulders for re-melting - waste not want not! Joining was carried...

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AN INTRODUCTION TO CATHODE RAY TUBE (CRT) MANUFACTURE

Posted by STEVE MYCIUNKA on

AN INTRODUCTION TO CATHODE RAY TUBE (CRT) MANUFACTURE

Well, a CRT is a thermionic electron tube so I thought we would follow our popular blog series on how valves were made with a similar one detailing the manufacturing process for CRT employed by Mullard. Let's start with the basics, we can list the CRT main component parts as the envelope, the electron gun and the screen. The envelope, consists of a funnel shaped glass bulb which was either round or rectangular in section and closed at it's widest end with a flat glass faceplate and terminated at the other end by a narrow tubular neck. The electron gun, produced a narrow beam of high...

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ADONIS & MARCONI OSRAM VALVES 1925

Posted by STEVE M on

ADONIS & MARCONI OSRAM VALVES 1925

Do you think this advert from 1925 is good? - I know my American friend Pamz will just LOVE THIS for Adonis is her nickname for ME! As we all know, Adonis is the perfect man, with a flawless physique, heart of gold and mind of steel, who makes hearts patter and gives girls butterflies in their stomachs with his presence. Hmmm, sounds like me but no references to toothpaste or dental floss!!!!!!!!!!! In Greek myth, Adonis was the son of Myrrha who was turned into a myrrh tree for incestuousness and gave birth to Adonis whilst in the form of a tree.  Adonis grew into an astonishingly handsome...

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MORE ON MULLARD DATE CODES - THE YELLOW PRINT VALVES

Posted by STEVE M on

MORE ON MULLARD DATE CODES - THE YELLOW PRINT VALVES

I am not going to get into the perennial discussion of the sonic properties of the yellow print valves over the stock boring white print ones but instead discuss A DIFFERENT advantage the yellow has over the prosaic white. Some of our eagle eyed readers will have noticed that the Yellow Print Old Shield Mullard valves have underneath the shield typically the valve notation in Mullard - Philips (ECC83) or even RETMA (12AX7) then underneath this is the elliptical BVA logo - just like for the white print valves....... But here's the rub - they yellow valves have a letter code...

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BRIMAR VALVE TYPE & DATE CODES - HOW TO INTERPRET THEM

Posted by STEVE M on

BRIMAR VALVE TYPE & DATE CODES - HOW TO INTERPRET THEM

Well, we did Mullard last week so this time, lets look at the Brimar type and date codes, oft seen on valve envelopes in minuscule inked print, but what do they mean? Brimar codes come in two parts separated by a forward slash "/". The first part, of format number-letter-number is the date code where the first number signifies production week of month, the following letter signifies the production month and the second number signifies the production year. First number: - 1 = week 1 of production month 2 = week 2 of production month 3 = week 3 of production month 4 = week 4 of production...

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