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Blog posts of '2012' 'February'

THE JAN CODE - WHAT DO THE ALPHANUMERIC AND ALPHA CODES MEAN?

Hi peeps, well, in response to another valve related query, this time about 'JAN codes', I thought I would pen a little information nuggett here today. I shall be doing a further more detailed blog entry on military coding history and types soon but for now here's a quick info - bite.

The JAN code is of course the US Military Joint Army Navy coding introduced in 1942 in which the code for a particular valve type comprises of an alphanumeric code, for example VT-114 and additionally a three digit alpha code. I will deal with the former in more detail later, but the alpha code is a manufacturer code. Here is a short listing of the most commonly seen codes with their corresponding manufacturers:-

CHS – Sylvania

CHY – Hytron or CBS-Hytron

CKR – KenRad

CL – GE

CRC – RCA

CRP – Raytheon

There have been multiple USN numbering systems in use over the years.

The initial numbering system was introduced in 1912 with the first of two letters signifying the device manufacturer followed by a sequentially assigned number to indicate valve type.

A replacement system was introduced in 1932 in which the two letter device manufacturer code continued but the numerical part was augmented into a 5 digit number in which the first two designated the valve classification and the successive three the specific type number.

This system was replaced in 1942 using the Joint Army Navy (JAN) system due to a larger range of valve types used in war materiel requiring classification.

 

AN INTERESTING QUESTION, WAS STANLEY MULLARD TOLERANT, TOURETTICAL OR TYRRANICAL?

As the new scion of Mullard, I have just received by e-mail a question as to whether or not SR Mullard was an unpleasant man to work with. Many had commented that Stanley was a ‘rough diamond’ with little formal education. Most of his bad press seems to stem from the contretemps between himself and CO Stanley in the days before CO was the owner of WG Pye. At this time, Mullard was looking for sales expansion and CO Stanley as the charismatic owner of the marketing agency ARKS, hit upon a grand scheme whereby a new magazine entitled Radio for The Millions would be produced which extolled the great virtues of Mullard’s PM series valves.

The first edition of the magazine was penned with a range of four tried and tested radio designs which could be built by the home constructor for as little as two pound and fifteen shillings. The idea was that funding for the magazine would be sponsored by component manufacturers but they were not particularly forthcoming and Radio for The Millions was majority funded by the Mullard Company. In a pilot study the initial uptake of this magazine was slow and CO Stanley hit on the idea of advertising in The Daily Mail hence ‘gifting the magazine to the nation’. All the interested public had to do was write to Mullard House and lo and behold a free copy would be sent to them by return mail. The only fly in the ointment was the cost of that advert in the Daily Mail which would cost some £900. Stanley Mullard didn’t want to stump up the dosh but the silver tongued CO Stanley talked him round.  The photos below show, on the left,  CO Stanley in 1929 and Stanley Mullard a little later in 1955.

The Daily Mail advert ran in early December 1926 appearing in a Saturday edition of the newspaper. Come Monday morning, Stanley Mullard and CO Stanley gathered at Mullard House to see what effect the advert had produced – the post came and went ............and not one single response was received as a product of this expensive advert. Stanley Mullard, it is said, exploded in apoplectic rage and was said to have roundly cursed CO Stanley in a particularly vile and vitriolic manner. This tirade went on for some time and was cut short only by the arrival of a special mail delivery – the response to the advert was so great that the volume of mail could not have been conveyed by a standard mail delivery!!!!! Stanley Mullard apologised and soon went on to reap the rewards of this campaign by capturing the valve supply for 25% of all radio receivers home constructed during the 1926 – 1927 financial year.

So, the above example portrays a brusque abrasive chap with a hair trigger temprement, however, it seems he was also capable of great empathy, kindness and concern for his employees. It is reported that Stanley Mullard spent a lot of time on the shop floor of the Mullard works, always keen to, as Tom Peters would say some 50 years later, ‘manage by walking round.’ Stanley would always listen to his workforce, particularly on advice of how to improve production methods. It is said that his staff were entirely loyal to him and not one employee withdrew their labour during the General Strike of 1926. Other examples of his empathy were demonstrated if an employee was found to be not performing, in which case they were give an two week leave of absence, if you had a managerial position, this was expanded to a four week leave of absence. This philanthropy came at a price as refreshed from your holidays one was then expected to then step up to the mark!

Some have postulated that Stanley’s lack of formal education was due to a mild form of dyslexia, however, this did not prevent him from running what was to become the largest and most revered valve manufacturer in the UK or once he left Philips-Mullard to become quite a celebrity within the rose and carnation growing circles. It is said that the Mullard family had a Siamese cat which was fond of – as cats are wont to do – to perambulate, micturate and defecate throughout the garden - even amongst the carnations and other shrubbery – did our Stanley's volatile temprement surface and was he ever heard to lustily bellow I’LL KILL THAT COOKING FAT! To that particular question, this scion cannot comment further.

 

 

WELL ENDOWED AND STILL EXPANDING - NOT ME SILLY - MULLARD FROM THE MID TO LATE 1950s!!

Ha-ha!  good title huh?  Actually, the latter half of the 50s decade didn't bring any further endowments for SS Eriks, however, expansions and improvements still continued unabated for the Mullard organisation.   Yes, it was all happening and at a prodigious rate too, for Blackburn, a new wire factory capable of drawing the tungsten-molybdenum wire used in valve manufacture was built in 1955, also in 1955 a new glass moulding factory was built at Blackburn capable of turning out 500000 parts per day.

In 1957,  the boffins got a look in too, the Research Laboratories at Salfords got a new applications building and a spanking new canteen too – keep em fed and keep the inventions rolling!   Whilst munching on a 'made in house – not bakery purchased sausage roll' in the new canteen, SS Eriks was heard to say that he wished he had a bigger office  - I wonder if  this was required to house his awards and photos of him with European Royalty and Heads of State, whatever it was, his wish came to fruition in 1957 when Mullard moved  from the Philips UK HQ  at  Century House, Shaftesbury Avenue to their new HQ building at Mullard House, Torrington Place, London WC1.  The distance moved was small - only about 1/2 a mile -  but the amount of extra space the move provided made it all worthwhile.
  
Also in 1957, the Southampton semiconductor plant opened at a greenfield site at Millbrook which interestingly enough was the first custom built facility for semiconductor manufacture to be built in the UK.   The embracing of new technologies was heralded in the form of financial aid  being provided by Mullard in February 1957 to kick start the Mullard Radio Astronomy Observatory for the University of Cambridge.  This exciting new facility, second only to Jodrell Bank in the UK was situated at Lord's Bridge, Cambridgeshire on the site of an old Royal Army Ordinance factory at which the railway line spur feeding  it was put to good use as the bed for the Ryle 5km radio-telesope.

1957 sure was a busy year as there was much  squabbling and unrest at the Croydon Beddington Lane service facility but by 1958, overcrowding was alleviated by the opening of a satellite service office again in Croydon, just down the road in Purley Way.

In 1959, Blackburn was again visited and a new chemical plant having pilot plant, kilo lab and a four reactor facility was built to allow synthesis of the specialised chemicals utilised in valve and capacitor manufacture.

MULLARD MUSTARDS OR C296 POLYESTER CAPACITORS

Well, I have broken off my series of Mullard historical blog posts to answer a query I have received from a customer about the so called Mullard Mustard capacitors.   These capacitors, introduced to the radio market in 1958 have a polyester dielectric which exhibits very low dielectric loss, high insulation resistance coupled with good temperature and moisture resistance.   In all these parameters they far exceed the efficiency of paper dielectric capacitors and impart a very similar audio signature I am told.

Throughout the 1960’s Mullard Mitcham conducted a whole raft of accelerated storage and use testing and found these are ultra stable, ultra reliable capacitors. Indeed ask many service men and they will tell you that never in their career did they need to replace one of the Mullard mustards due to failure in use. It is because of this reliability and  intrinsic audio characteristics that these are sought today for use by audiophiles and guitarophiles ( - is there such a word?).     Actually, the serviceman probably would not refer to them as Mullard Mustards but rather Mullard polyester capacitors  C296A.

I have been asked what these codes mean, well, the prefix C stands for capacitor, 296 is the series type of the capacitor, the series type notation is followed by either  AA for 160V rating or AC for 400V rating.    The coding will then continue in the form C296Ay/xxx. where the first (post slash) letter that indicates the tolerance of the capacitor.  In the case of the 296 series, A = +/- 10%. The numerical component denotes the capacitance value of the device.    Let us use the lowest value available of 0.001uF which can equally be expressed as 1nF.    

This will appear on the device as 1K giving, for a 400V device the full code C296AC/A1K.   Similarly for an 0.033uF 160V device, the full code would be C296AA/A33K.    In the same fashion for a 0.22uF 400V device, the full code would be C296AC/A220K.

In summary, one can always easily read the capacity of the device by considering the letter K to equate to the unit nF and the numerical component to be the value.  To translate an nF value into other units of capacitance, the following conversion factor may be applied.

1uF = 1000nF = 1000000pF

Anyhow, because I am a top geeza, I have produced a table showing the ENTIRE range of C296 capacitors ever made with their corresponding codes and capacitance values in various Farad units - pretty good huh?

TYPE NUMBER

CAPACITANCE (uF)

CAPACITANCE (nF)

CAPACITANCE (pF)

WORKING VOLTAGE  (V)

 

 

 

 

 

C296AA/A10K

0.01

10

10000

160

C296AA/A15K

0.015

15

15000

160

C296AA/A22K

0.022

22

22000

160

C296AA/A33K

0.033

33

33000

160

C296AA/A47K

0.047

47

47000

160

C296AA/A68K

0.068

68

68000

160

C296AA/A100K

0.1

100

100000

160

C296AA/A150K

0.15

150

150000

160

C296AA/A220K

0.22

220

220000

160

C296AA/A330K

0.33

330

330000

160

C296AA/A470K

0.47

470

470000

160

C296AA/A680K

0.68

680

680000

160

C296AA/A1M

1

1000

1000000

160

C296AC/A1K

0.001

1

1000

400

C296AC/A1K5

0.0015

1.5

1500

400

C296AC/A2K2

0.0022

2.2

2200

400

C296AC/A3K3

0.0033

3.3

3300

400

C296AC/A4K7

0.0047

4.7

4700

400

C296AC/A6K8

0.0068

6.8

6800

400

C296AC/A10K

0.01

10

10000

400

C296AC/A15K

0.015

15

15000

400

C296AC/A22K

0.022

22

22000

400

C296AC/A33K

0.033

33

33000

400

C296AC/A47K

0.047

47

47000

400

C296AC/A68K

0.068

68

68000

400

C296AC/A100K

0.1

100

100000

400

C296AC/A150K

0.15

150

150000

400

C296AC/A220K

0.22

220

220000

400

C296AC/A330K

0.33

330

330000

400

C296AC/A470K

0.47

470

470000

400

 

The C296 series of capacitors also carry a three digit batch code of the form A8B

Where digit 1 is the quarter code: - A = January - March; B = April - June; C = July - Spetember; D = October - December.

Where digit 2 is the year code: - 1 = 1961; 4 = 1964 etc....

Where digit 3 is the manufacturing plant: - B = Blackburn; D = Hamburg: S= Barcelona;