Identifying these Valvos.

[Hmmm]

Hi- Cool forum and pleased to be here.

Got a question:

Recently bought some Valvo 6201s 12AT7WAs. Their codes are:

Df6-D8L2 ; Df6-D8I4 ; Df6-D1k2

Could anyone tell me their year of manufacture? I've been informed that DF6 corresponds to sometime between 60 and 64 but also as late 50s or even 70s?

An externally hosted image should be here but it was not working when we last tested it.

and are they the same as the one on Tube Classics described as a 6201 DF6 DX closed getter?

http://www.tube-classics.de/TC/Tubes/Valvo ECC81/ECC81.htm

An externally hosted image should be here but it was not working when we last tested it.

Many thanks!!

 

[kstagger]

Valvo was owned by Phillips

see here for Plant Codes
http://www.audiotubes.com/mullcode.htm

 

[Hmmm]

Thanks for your reply.

That Audiotubes page isn't the easiest to understand.

However, I've taken a second look at the Tube Classics website and they have a page on 'understanding codes' here:

http://www.tube-classics.de/TC/Tubes/Valvo/Phlipscode.htm

First thing of note is that it says:

"Tubes BEFORE 1960 have a second line with only 3 digits".

So, if we take one of the codes I mentioned in my opening post (e.g DF6 on the first line and D1K2 underneath on the second line ) and use the Tube Classics page for indentifying its code we get the following:

DF = ECC81
6 = Construction type

on the second row there are four numbers, not three, so must be sixties, right?

D = Hamburg
1 must = 1961 (??)
K = month
2 = second week.

Unless I'm mistaken, that tube is from 1961 and the other two I mentioned are from 1968 because they have 8 instead of 1.

Interesting, because the seller of those tubes said they were all from the fifties. Hmmm