12AT7HJ Pre Amp tubes (ECC81)
Dramatically increased sound quality over the standard 12AT7HJ tubes
Gold coated pins to enhance connection over long term
All parts are selected to the highest grade plus only highly experienced workers used to assemble
Suggested burn-in time is 75-100 hours
12AT7HJ Pre Amp tubes are Sold in Pairs
Filament heating
UH —————————- 6.3 (and) 12.6 (string) V
IH —————————– 0.30 0.15 A
Electrode capacitance
Gate – gate ———————- 0.005 PF
Anode – anode ———————- 0.4 PF
Gate – the anode (single transistor) ———– 1.5 PF
Gate – cathode filament (single transistor) —— 2.2 PF
Anode – cathode filament (single transistor) —— 0.5 PF
The filament – cathode (single transistor) ———– 2.4 PF
Anode – cathode (single transistor) ———– 0.2 PF
Cathode – the filament, the gate (single transistor) —— 4.6 PF
Anode – a filament, the gate (single transistor) —— 1.8 PF
Static parameters
Ua ——————– 100 250 V
Ia ——————— 3.7 10 mA
Gm ——————– 4 5.5 mA / V
Rk ——————— 270 200 Ω
u ———————- 60 60
ri (approx) ————— 15 10.9 KΩ
Ug (approx) ————— 5 -12 V
(When Ia = 10uA)
A1 amplify limits (single transistor)
Anode voltage ——————- 300 V
Anode power dissipation ————— 2.5 W
Gate voltage ——————– 50 V
Filament cathode voltage (pk) ———– ± 90 V
Gate resistance
Since bias ——————- 1 MΩ
Fixed voltage —————– 0.25 MΩ
