Valve AF 7

Dear Radiofiles,

I have one valve AF 7 which base is B5,not eight pin P as shown on my manuals and also in  Rmorg.The brand is KLANGFILM,and under the type AF 7 are the letters S P Z.I would like to know which electrodes go to each pin,apart the heater which are pins 2 & 3.Should this be a diferent or special AF 7 type?Can anyone put some light on my doubts?Thanks in advance  A.B.Regada

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Can you show us a photo?
 

Regards WB.

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Hello Mr Bauert,

Unsure about a first upload,please find the requested photo.Regards,A.B.Regada

• valve AF (25 KB)

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Dear Antonio,

to a certain degree this appears to me as homebrew, i.e. as if someone took a normal AF7 and put it into a B5 base, particularly because of that groove in the upper section of the base.

Since the control grid # 1 is invariably on the top cap, the base diagram is most probably the same as of the BL2, a penthode, which also has a B5 base and grid # 1 on the top cap, - however without warranty.

Unfortunately I have no special documents about Klangfilm and I never heard anything about this special AF7.

Best Regards, Jacob

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Hello Jacob and Antonio,

re: the Klangfilm AF7 SPZ tube photo. 
Is it quite possible that the tube may be an early audio amplifier tube 
for the large theaters (for the "talkies") or even for the telephone 
"line amplifiers". . . could that be one explanation for the marking 
SPZ on the tube. 

A very few of the tubes produced by Klangfilm even had different base 
identifications of G5K or G7K instead of the B5 base. The photo submitted 
of the base is difficult to positively identify the pins arrangement. 

Some Google searching last night referred to that possibility; and also 
references in the web site by one of our members from Norway.

NOTE: Siemens also produced the "weitverkehrsrohren" series of tubes - I 
thought that meant the "long pipe" or similar to the telephony systems! 

Respectfully,
Robert

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