Hi there,
Looks like you got it grasshopper. The 5 vs. 6 is just the change code; as Brent says it is meta-detail about the production run. I'll bet you could find tubes produced in the same plant, same year, month, week, bu tmaybe have a unique change code meaning a particular machine? Who knows?
What I have gathered is that pre-1956 you will just have two digits on the row; as Brent says, you could extrapolate the month and year using the change code (last digit on top row) and the month code (2nd digit on bottom).
So when you have 3-4 digits in the bottom row, you are post-1956 and it's easy to pinpoint the year and month and week.
cheers,
DC
Hi,
I'm a novice, trying to learn fast, but I can't figure out how to decipher these tube codes: VR6 (delta)3B3 and VR5 (delta)2G5. I've checked out http://www.audiotubes.com/mullcode.htm and this is where I am so far - would appreciate it if someone could fill in the gaps/straighten me out?:
VR = E188CC
6 or 5 = ???
(delta) = Philips Heerlen factory
3B3 = 1963? Feb 3rd week?
2G5 = 1962? July 5th week?
Cheers
Will
