HI All,
I am just beginning my journey with vacuum tubes and was hoping to build an amplifier. I picked up a mixed box of old/used/nos tubes that contains 16 x 6CM5 (EL36?) tubes that may be candidates for an amplifier. I have noticed several brands of tubes (AWA, Mini Watt, Radiotron, Toshiba) with either 5, 6 or 7 pins on the base. I don't have a tube tester yet but thought I would just check continuity for the heater between pins 2 and 7. This checks fine for all the tubes but I also get continuity on pins 3 to 8 on the 6 and 7 base pin models. Is this correct or are these tubes shorted ? I managed to find several datasheets but that often indicates pin 3 is an "Internal connection".
Any help appreciated, clearly I have a way to go 🙂
Richard
I am just beginning my journey with vacuum tubes and was hoping to build an amplifier. I picked up a mixed box of old/used/nos tubes that contains 16 x 6CM5 (EL36?) tubes that may be candidates for an amplifier. I have noticed several brands of tubes (AWA, Mini Watt, Radiotron, Toshiba) with either 5, 6 or 7 pins on the base. I don't have a tube tester yet but thought I would just check continuity for the heater between pins 2 and 7. This checks fine for all the tubes but I also get continuity on pins 3 to 8 on the 6 and 7 base pin models. Is this correct or are these tubes shorted ? I managed to find several datasheets but that often indicates pin 3 is an "Internal connection".
Any help appreciated, clearly I have a way to go 🙂
Richard
This tube only has 5 useful connections on the octal socket. The extra pins, if they are present at all, are just additional mechanical supports for the electrodes. They may be connected to other pins, this was a manufacturer choice. Pin 3 is one of the extra pins, so don't worry about continuity to other pins.
