eBay

FYI: These tubes are measured in autobias mode according the manufacturer data sheet.More information you find at the end of this describtion

2 x tubes E81CC = ECC801s 12AT7WA Siemens Halske

The print is little bit weak due the age . The tubes itsself are unused and test really perfect.

matched pair

Measured in autobias mode

Emission = Gm 7,200 + 7,200 and 6,900 + 7,000(new = 5,500mA/V >4,500...6,500< )

Anode current Ia: 14,0mA + 14,4mA and 13,9 + 14,0mA (100% = 10,5mA ±1,8mA)

Please do not confuse "S / gm" with "Ia".
Only the value s / gm says something about the emission and thus the life time
Measuring device used: RoeTestV11.
Measurement mode: Autobias as specified by the manufacturer.
In autobias mode the tube is measured with a constant anode current. This corresponds to the application in the device.
Note: Most tubes offered on ebay are tested with a fixed grid bias voltage. Such a measurement contains a general system error. The desired result in the application is therefore purely random.