Single-Ended Triode
22W845 SE Classic
RCA 845 transmitting triode in SE configuration. Even higher voltage than the 211 with a more linear transfer characteristic. Massive, effortless power.
RCA 845 DatasheetAmpera
845 Triode Vacuum Tube
Triode10V / 3.25AUX-4SPICE
Power triode delivering 100W for push-pull and SET designs
Datasheet ↗SPICE
5
1.7kΩ
3.3mA/V
5.0pF
13.5pF
3.50pF
GAIN5%
POWER100%
DRIVE98%
LINEARITY95%
SPECIFICATIONS
Heater10 V · 3.25 A
Max Plate Voltage1250 V
Pa max100 W
Gain Factor5
gm3.3 mA/V
rp1.7 kΩ
Inter-electrode capacitances
Cgk5 pF
Cgp13.5 pF
Cpk3.5 pF
PinoutUX-4
Era1931
RarityModerate
Source datasheets
2 manufacturer datasheets cross-checked for 845
TYPICAL OPERATING POINT
SPICE model(2 available)3 .subckt available ↓
EXECUTIVE SUMMARY
The 845 is a transmitting triode closely related to the 211 but with a higher amplification factor (mu ~8 versus ~12 for the 211), originally made by RCA and Amperex. Operating at plate voltages of 800-1250V, it delivers 15-30W in single-ended Class A with a slightly warmer, fuller tonal balance than the 211. The 845's higher mu means it requires less drive voltage, simplifying the driver stage design somewhat. It shares the 211's dramatic visual presence with its bright thoriated-tungsten filament, and the two are often compared as complementary voices in the DHT transmitting triode world.
APPLICATIONS
SET outputPush-pull outputHeadphone output
Cary CAD-805Mastersound 845 integrated
• Headphone amp• PA/public address
HISTORY
Introduced1931ManufacturerRCA
Pre-WarMETRIX TESTER
Test this tube on a Metrix
CLASSIC CIRCUITS