What make of tube is this 6201?

[oztayls]

I have a pair of these in plain boxes. All I know about them is they are 12AT7 equivalent. the only marking on the tube is USA followed by a triangle shape and the numerals 6201 at the top.

 

[GordonW]

That is a General Electric. The dot pattern and the particular font of the lettering is a dead-on indicator of that.

Those are usually very good tubes. It's a 12AT7 equivalent, with some slightly enhanced specs (the most relevant is that the max heater-cathode voltage is 100V, whereas most other 12AT7-equivalents are only 90V).

Regards,
Gordon.

 

[oztayls]

Wow, thanks Gordon! Interesting.