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6A8 — Hexode, Octal | Tubeofile
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6A8
Hexode — Octal
···
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Known Equivalents & Substitutes
6A8G
6A8GT
CV579
VT151
Similar Tubes (Not Drop-In Compatible)
6BE6
Miniature (B7G) successor pentagrid converter — electrically similar but different base
6SA7
Improved pentagrid converter successor with better conversion gain — different pinout, not a drop-in
7B8
Loctal version of the pentagrid converter family — similar function but different base
Electrical Specifications
Absolute Maximum
Anode Voltage (max)
Max Plate Voltage
300
V
Screen Voltage (max)
Max Screen Voltage
100
V
Anode Dissipation (max)
Max Plate Dissipation
1
W
Screen Dissipation (max)
Max Screen Dissipation
0.3
W
Typical Operating
Notes
The 6A8 uses a top-cap connection for grid #1 (oscillator grid) — requires clip lead.
GE data shows identical specs for 6A8, 6A8-G, and 6A8-GT variants.
Sams lists substitutes: PH4, X63, 19SU.
Conversion transconductance 550 umhos at Va=250V, Vg2=100V, Vg1=-3V.
Max plate dissipation 1W, max anode voltage 300V, max screen voltage 100V.
Pin Layout — Octal
1
2
3
4
5
6
7
8
1
Shell (Metal) / No Connection (Glass)
2
Plate
3
Grids 3 & 5 (Screen)
4
Anode Voltage (typical)
Plate Voltage
250
V
Grid 1 Bias Voltage
Control Grid Voltage (Grid 4)
-3
V
Screen Voltage
Screen Voltage (Grids 3 & 5)
100
V
Anode Current
Plate Current
3.5
mA
Screen Current
Screen Current
2.7
mA
Anode Resistance
Plate Resistance
360,000
Ω
Transconductance
Conversion Transconductance
0.55
mA/V
Heater
Heater Voltage
Heater Voltage
6.3
V
Heater Current
Heater Current
0.3
A
Grids 2 & 4 (Oscillator Anode)
5
Grid 1 (Oscillator Grid)
6
No Connection
7
Heater
8
Cathode
TC
Top Cap —
Grid 4 (Signal Grid)