EL34 identification

[astouffer]

Yes its time to play guess who made this EL34. Found this in my collection and it is the one lone example. No markings at all except for the pins which are numbered on the bottom. Any ideas?

 

[Koonw]

The spot welded plate (with 2 small windows) is probably Chinese, but best matched I found as attached. Noted the same electrodes color and mica. Just a guess.

 

[Parafeed813]

Curious, those extra small fins (on g2?).
I can't find those on the Philips, Mullard, Telefunken, RFT, Tesla, Chinese or Russian versions I have.
Are these recent or old production?

 

[Koonw]

Building the Shuguang EL34-B Vacuum Tube - Part 1 - YouTube
Screen cooling fin is mentioned in the above video.

 

[Alan4411]

99% It is a Mullard (Philips family).
Typical Mullard are the; micas, the 'point' on the pins, the getter bowls, the anode 'slots' and welding. Some do have little 'fins' on the anode rods to stabilise the micas.

Is there a hole in the middle of the spigot?
Is there any evidence of lettering on the glass close to the black base?

 

[Parafeed813]

Any etched codes on the glass near the base?

 

[Kay Pirinha]

Your tube indeed shows several signs of having been made somewhere in the Philips group. As such there should be an etch code next to the phenolic base, as yet mentioned. Is it's pin #6 omitted?

Best regards!

 

[martyh]

My bet... the code is XF2

 

[astouffer]

All the pins are present and yes there was a near invisible code etched into the bottom of the glass B3H4.

 

[martyh]

That is the bottom section of a mullard blackburn code. I'm still betting above that was XF2

 

[astouffer]

Shining a flashlight on the glass there does appear to be XF2 above the previous code. Thanks everyone.

 

[Alllensoncanon]

All the pins are present and yes there was a near invisible code etched into the bottom of the glass B3H4.

B = Blackburn factory
3 - 1963 or 1973 depending on revision number xf?
H = August
4 = 4th week

 

[jgf]

Is there a hole in the guide pin? Is that exclusive to Mullard/Philips?