[Oskari]

Quote:

You must pay attention to the construction, plates, getter etc to be sure.

 
Indeed. Not to forget the ever-helpful codes that most tubes of the Philips group carry.
 

1. http://frank.yueksel.org/other/Philips/PhilipsCodeListAB-v10.pdf
2. http://frank.yueksel.org/other/Philips/PhilipsCodeList.pdf

 

[rosgr63]

Oskari, thanks for the great references.

 

[Oskari]

You're welcome! Not the first time I posted them; probably not the last time either. 

 

[rosgr63]

Indeed, I have the pdfs in my tube database and use them when I need to.
 
You are the Mullard expert who understands how to decipher them, I often struggle with them.

 

[dminches]

Can those code rules be applied to Philips EL84s, for example?

 

[rosgr63]

They apply to any/most Philips Mullard tubes.
 
Part of the code refers to the tube type.
 
I have to make any sense of them yet!!!!!!!!!

 

[Oskari]

Quote:

Can those code rules be applied to Philips EL84s, for example?

 
Yes, they can. Some examples can be seen at
 
http://www.tube-classics.de/TC/Tubes/Valvo%20EL84/EL84.htm
 
but note that the Heerlen factory symbol is a right-angled triangle, not the Δ character shown.

 

[dminches]

So, how do you translate fx1 B7K?

 

[Oskari]

Quote:

They apply to any/most Philips Mullard tubes.

 
Yes, most tubes made (or marketed) by Philips and their many subsidiaries and associated companies. There are, naturally, exceptions; e.g., very old tubes predate the system, and I don't think that Philips ECG (formerly Sylvania) tubes ever carried the codes.

 

[Oskari]

Quote:

So, how do you translate fx1 B7K?

 
Please check the first two characters. fx doesn't seem to exist. Case matters! This is the type code.
 
1 = some kind of a version or revision or batch number
B = Mullard at Blackburn; 7 = generally 19?7, in this case 1957; K = November

 

[Skylab]

rX = EL84 so I bet it's an r not an f

 

[Oskari]

Of course. Short memory.

 

[dminches]

Quote:

 
Please check the first two characters. fx doesn't seem to exist. Case matters! This is the type code.
 
1 = some kind of a version or revision or batch number
B = Mullard at Blackburn; 7 = generally 19?7, in this case 1957; K = November

 
My bad.  The first 2 codes are fX = E33CC

 

[Oskari]

Quote:

My bad.  The first 2 codes are fX = E33CC

 
If the tube is an EL84, this code must be rX. That's an easy mistake to make. Trust me.
 
If the code really is fX, you have found something nonexistent in this reality, be that an E33CC or an E35CC like the other document lets us believe. (Quite a coincidence considering the title of this thread!) You must show us photographs of this marvel. Pronto.

 

[dminches]

I guess I confused everyone by first asking if the codes apply to EL84s and then posting the code of an E33CC.  They were 2 different questions.  The code of the E33CC was for an item for sale on ebay.  I asked the EL84 question is I want to now go back and see which EL84s I really have.