6DJ8
The 6DJ8 (European type ECC88) is a dual triode tube with a 6.3 V, 365 mA heater and a 9-pin miniature base.
With 15 mA of plate current, 90 V plate-to-cathode voltage, and -1.3 V grid-to-cathode, the 6DJ8 provides 12.5 mS of transconductance with a plate resistance of about 2.5 kΩ.
The 6DJ8 is used in many Tektronix instruments of the tube era.
As of 2012, 6DJ8 tubes are still manufactured and used and new old stock (NOS) 6DJ8s can also be obtained easily.