help identifying 12ax7's please...

susanb · Post by **susanb** » Fri Dec 09, 2005 5:05 am

hi,

does anyone know who these are made by and the approximate date of manufacture?

http://myweb.tiscali.co.uk/keggler/Images/12ax7.jpg
http://myweb.tiscali.co.uk/keggler/Images/12ax7-too.jpg

btw, on the "too" image, it's got 7148 below an upward facing arrow punched on it, and there are none of these Bxxx codes like on the 1st image...

thanks...

clarkydaz · Post by **clarkydaz** » Fri Dec 09, 2005 5:15 am

they appear to be mullards. the second one with the CV should be a military grade mullard, though the code usually is cv4004 for the ecc83s, not sure how that differs. the military mullards are more expensive, i have a few but dont like them in guitar amps. they make things too hifi. the regular mullards have the sweetness and warmth

novosibir · Post by **novosibir** » Fri Dec 09, 2005 6:42 am

The first one definitely is a Mullard - made in the second week of May 1970. The second one I don't know, but maybe also a Mullard.

Look for the "B" code on the envelope near the bottom!

Larry G

susanb · Post by **susanb** » Fri Dec 09, 2005 7:56 am

thanks for your advice you two - i'll have a look...

just a poor girl trying to identify some valves for my PhD thesis...

susan

Guest · Post by **Guest** » Fri Dec 09, 2005 3:11 pm

Most real Mullard have a seam in the glass on top of the tube.

susanb · Post by **susanb** » Sat Dec 10, 2005 3:53 am

ah, ha - thanks once again - i have two examples of the first pic, and both have a "seam" at the top of the glass and the "B" (Blackburn) code...

Post by **VelvetGeorge** » Sat Dec 10, 2005 12:24 pm

Congrats, you've got real Mullards. Next you should look at the plates to see which version you have.

George

susanb · Post by **susanb** » Wed Dec 14, 2005 3:55 pm

hi George,

is this the "long plate" / "short plate" thing?

or these "square getters" / "round getters" thing?

bit confused about these things just now...

susan