805A  is direct-heated type thorium tungsten cathode triode, can be used as class B, A-F, and R-F power amplification, class C R-F power amplification and high frequency oscillation.

Heater
Uf--------------------------------------10 V
If---------------------------------------3.25 A

Direct Interelectrode Capacitances
input----------------------------------8.5 PF
output----------------------------------10.5 PF
grid to plate---------------------------------6.5 PF

Maximum Rating
Ua---------------------------------1500 V
Pa-----------------------------125 W

Recommended Operating Conditions (reference value)

class B(A-F) for two tubes
typical working condition    limited parameter 
Ua------------------ 1250 1500 1250 V
Ia (mAx.sig per tube)------------------- 210 mA
Pa (in) (mAx.sig per tube)--------------- 315 W
Pa (per t ---------------------------- 125 W
Ug----------------------------------—16 V
Ug(pk)----------------235 280 V
Ia (0)-----------------148 84 mA
Ia（mAx.sig）----------500 600 mA
Pd(mAx.sig)------------6 7 W
RL(a—a)---------------6.7 8.2 KΩ
Pout(mAx.sig)-----------300 370 W

class B(R-F)：
Carrier conditions the biggest modulation coefficient is 1 per tube

typical working condition    limited parameter 
Ua------------------ 1250 1500 1500 V
Ug----------------------------------—10 V
Ia -------------------135 115 150 mA
Pa (in) ------------------------------185 W
Pa ---------------------------------125 W
Ug(pk)----------------70 70 V
Ig -------------------15 15 mA
Pd-------------------11 7.5 W
Pout------------------55 57.5 W