CV181-Z
Uf 6.3V Ua 250v Ug1 -2V
Plate current Ia1 9.5 mA Ia2 9.5 mA
300B-Z
Uf 5V Ua 300V Ug1 -60V
Ia 55mA
845-T
Filament current at Ua 10 V 3.25A
Plate current at Uh 10V Ua 1250V Ug1 -200V measure value 60 mA
ลองดูนะครับ ที่มีเปรียบเทียบคือ CV181-Z match pair B grade Ia1 6.5 mA Ia2 6.5 mA ครับ
สำหรับ 300b 845 ไม่ได้สั่งมาเทียบกันครับ
I talked to the seller in China, they told me that 300B-Z, if Ia under 60mA, it will be in original single tube box, while a matched pair will be 60mA++ in collector box. I have 2 pairs of 300B-Z at 72mA and 85mA. CV181-Z , normal version is less than 9mA, while high price version is 9-11mA. The "GRADE" that the seller in N.America claimed A or B, is it just a marketing stuff for piece of mind?