This auction is for 2 pcs 5751 (ECC83 12AX7) General Electric, made in USA with black plates, triple micas and square getter, a twin triode. They come in very safe military foam boxes. 
Tested on my valve characteristic meter AVO Mark 4.


Tube1: Ia1=1,30mA gm1=1,10mA/V Ia2=1,25mA gm2=1,25mA/V
Tube2: Ia1=1,00mA gm1=1,25mA/V Ia2=1,00mA gm2=1,25mA/V

Nota Bene: Is a tube new or not? Not always easy to know. The main parts of my tubes comes from the military and they sometimes bought  tubes in bulk-packages (without boxes) so they re-boxed the tubes either in white military paper-boxes or in very safe foam boxes. They also tested the tubes every 5 years which also was a rejuvenation of the tubes which makes them better than NOS tubes never rejuvenated. But this handling of the tubes could also result in some loss of printing on the tubes and depending on how you look at it, used. 

Due to russian war in Ukrain I will not ship to Russia or Belarus

Registered shipping worldwide is 14 usd.