Psvane MARK TII Series tube have two sub version : TII Classic version Or TII Collector version

The difference between Classic version and Collector version : It's from the same production line, the best appearance, the best electronic parameters and the timeproof tubes will be selected to Collector Version. The standard quality tube will class to Classic Version.  
​There are the same selection method in the vintage tube, like telefunken select the best ECC83 to create E803CC, Mazda select the best 12AX7 to create their 5 star 3 mica 12AX7 for military or other important instrument use case

Classic version tube is packed with for each tube a small box if you purchase tube only:

Collector version tube is packed with for 2x tube a bigger stronger box like next photo, the box is for two tube, if you purchase 3 collectors tubes, that we will send you 2 tube in bigger box and another tube with a small paper box:

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CV181 – TII centre U style audion

used in voltage amplification circuit.

can direct replace 6N8P and SN7GT

Filament heating voltage

UH………… 6.3  V

IH ………… 0.6     A

static parameter

Ua ………………………… 90     250 V

Ug…………………………   0      -8V

Ia  …………………………  10     9 mA

Gm…………………………  3      2.6 mA/V

Ri  ………………………… 6.7    7.7  kΩ

μ …………………………   20      20

Ia @Ug=-12.5V            _         1.3mA

Ug@Ia=-10uA              -  7      -18V

Limit rating

Class A1 amplification (per side)

Ua………………………… 450V

Ik………………………… -20mA

Pa ………………………… 5w

Pa(No.1+No2)   ………… 7w

Rg            ……………… 1MΩ

Uhk           ………………±100V

All these tube are factory matched tubes