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6F6 — Power Pentode, Octal | Tubeofile | Tubeofile
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6F6
Power Pentode — Octal — RCA
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Data: High
High quality — base, heater, all universal parameters present, and ≥50% of desirable parameters filled in. Safe to use for design decisions.
↗ r-type.org
↗ TDSL
↗ Radiomuseum
Known Equivalents & Substitutes
6F6-G
6F6-GT
42
2A5
CV1076
VT-66
1611
1613
6F6MG
CV1912
12C
6F6S
6F6M
Similar Tubes (Not Drop-In Compatible)
6K6GT
Same octal base and pinout, similar power pentode but lower Pa_max (8.5W vs 10.5W) and slightly different characteristics
Electrical Specifications
Section 1 — Pentode
Absolute Maximum
Anode Voltage (max)
Anode Voltage (max)
375
V
Screen Voltage (max)
Screen Voltage (max)
285
V
Anode Dissipation (max)
Anode Dissipation (max)
10.5
W
Screen Dissipation (max)
Screen Dissipation (max)
3.5
W
Notes
Electrically identical to type 42 (6-pin base) and type 2A5 (6-pin base, 2.5 V heater) except for heater ratings and base.
Grid-No.1 circuit resistance: 0.1 MΩ max for fixed-bias, 0.5 MΩ max for cathode-bias.
The 6F6-G (ST glass) and 6F6-GT (tubular glass) envelopes have identical electrical ratings to the metal 6F6.
RCA AN-52 (1935) documents Class AB push-pull triode connection of type 6F6, achieving up to 18.8 W output.
Pin Layout — Octal
1
2
3
4
5
6
7
8
1
No Connection (shell on metal type)
2
Heater
3
Anode (Plate)
4
Socket-Compatible Tubes
⚠ Not electrically compatible
12AV5
12AX4
12DQ6
12E1
12J5
12J5GT
12W6GT
1H4
25L6GT
350B
367A
5881
6550
6A5G
6C2C
References
https://frank.pocnet.net/sheets/028/6/6F6.pdf
https://frank.pocnet.net/sheets/127/6/6F6.pdf
https://www.one-electron.com/Archives/RCA/RCA-AppNotes/RCA%201935%20AN-52%20Class%20AB%20Operation%20of%20Type%206F6%20Tubes%20Connected%20as%20Triodes.pdf
Cathode Current (max)
Cathode Current (max)
45
mA
Heater-to-Cathode Voltage (max)
Heater-to-Cathode Voltage (max)
200
V
Max Grid Resistor
Max Grid Resistor (cathode bias)
0.5
MΩ
Typical Operating
Anode Voltage (typical)
Anode Voltage (typical)
250
V
Screen Voltage (typical)
Screen Voltage (typical)
250
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-16.5
V
Anode Current
Anode Current
34
mA
Screen Current
Screen Current
7
mA
Anode Resistance
Anode Resistance
100,000
Ω
Transconductance
Transconductance
2.5
mA/V
Output
Output Power
Output Power
3.2
W
Load Impedance
Load Impedance
7,000
Ω
Capacitances
Grid-to-Plate Capacitance
Grid-to-Plate Capacitance
0.7
pF
Input Capacitance
Input Capacitance
7
pF
Output Capacitance
Output Capacitance
11
pF
Section 2 — Triode Strapped
Absolute Maximum
Anode Voltage (max)
Anode Voltage (max)
375
V
Typical Operating
Anode Voltage (typical)
Anode Voltage
250
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-20
V
Anode Current
Anode Current
36
mA
Anode Resistance
Anode Resistance
3,100
Ω
Transconductance
Transconductance
2.6
mA/V
Amplification Factor (μ)
Amplification Factor (μ)
8
—
Output
Output Power
Output Power
1.6
W
Load Impedance
Load Impedance
5,000
Ω
Heater
Heater Voltage
Heater Voltage
6.3
V
Heater Current
Heater Current
0.7
A
Screen Grid (g2)
5
Control Grid (g1)
6
No Connection
7
Heater
8
Cathode and Suppressor Grid (g3)
6CD6G
6EN4
6J5
6K6
6L6
6L6GC
6M6G
6N3C
6P3P
6P6S
6S2S
6S41S
6V6
6W6
6Y6
7027A
7581
CV1135
EL32
EL34
EL37
EL38
EL39
KT120
KT150
KT170
KT63
KT66
KT77
KT88
KT90
PL38