Model: Hifi 845
Replace other 845 tubes directly
Factory Test&Matched Pair
The price is for 1 Pair/lot
845 is direct-heated type thorium tungsten cathode triode, class A1 and AB1
Heater
Uf---------------------------------------10 V
If----------------------------------------3.25 A
Maximum Rating
Ua----------------------------------1250 V
Pa-------------------------------75 W
Pout(max.sig)--------------------------150 W
Ia(max)------------------------------120 mA;
Direct Interelectrode Capacitances
input----------------------------------6 PF
output----------------------------------4.5 PF
grid to plate----------------------------------14.5 PF
Static parameter
Ua--------------------------------------1250 V
—Ug-------------------------------------200 V
Ia---------------------------------------80 mA
Gm--------------------------------------3 mA/V
ri----------------------------------------1.7 KΩ
u----------------------------------------5
RL---------------------------------------3.4 KΩ
Ug(pk)------------------------------------69 V
Pout-------------------------------------15 W
Recommended Operating Conditions（reference value
class A1 .single tube：
Ua-----1000 1000 1250 V
—Ug--- 145 155 209 V
RL-----6 9 16 KΩ
Ia------90 65 52 mA
Gm-----3.1 — — mA/V
Ug(pk)--— 110 148 V
ri------1.7 1.9 2.1 KΩ
Pout----24 21 24 W
Push-pull.class AB1：
Ua------------------ 800 1000 1000 1250 V
—Ug---------------- 125 170 175 225 V
RL------------------ 4.5 4.6 4.6 6.6 KΩ
Ia--------------------80 70 40 40 mA
Ug(pk)----------------177 240 — — V
Ia（mAx.sig）---------170 230 230 240 mA
Pout----------------40 75 75 115 W
