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7027A — Beam Tetrode, Octal | Tubeofile
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7027A
Beam Tetrode — Octal
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Known Equivalents & Substitutes
No known equivalents. If you know of any, use the ⚑ Report Issue button above.
Similar Tubes (Not Drop-In Compatible)
6L6GC
Same 6L6 family with same pinout but lower plate and screen voltage ratings (450V vs 600V)
KT66
Sams lists KT66 as substitute for 7027 — GEC beam tetrode with similar application
KT88
Sams lists KT88 as substitute — GEC beam tetrode with higher ratings, same Octal pinout
Electrical Specifications
Absolute Maximum
Anode Voltage (max)
Plate Voltage (max)
600
V
Screen Voltage (max)
Screen Voltage (max)
600
V
Anode Dissipation (max)
Plate Dissipation (max)
35
W
Screen Dissipation (max)
Screen Dissipation (max)
5
W
Heater-to-Cathode Voltage (max)
Heater-to-Cathode Voltage (max)
Heater
Heater Voltage
Heater Voltage
6.3
V
Heater Current
Heater Current
0.9
A
Notes
The 7027A supersedes the original 7027 with improved ratings.
Push-pull Class AB1 with fixed bias at Va=450V, Vg2=350V delivers 76W from two tubes into 6500 Ω plate-to-plate.
Push-pull Class AB1 with cathode bias at Va=425V, Vg2=425V, Rk=200 Ω delivers 44W from two tubes into 3800 Ω plate-to-plate.
Maximum ratings (push-pull): Va=600V, Vs=600V (screen grid tied to tap on output transformer primary), Pa=35W, Ps=5W.
Rg_max: 0.1 MΩ (fixed bias), 0.5 MΩ (cathode bias). Peak heater-cathode voltage: 200V (either polarity).
Base is Small-Wafer Octal 8-Pin with '950' Sleeve (JEDEC Group 1, B8-191). Basing designation 8MY (bottom view).
The 7027A has no exact pin-for-pin equivalent. KT88 is listed as a Sams substitute but has different characteristics.
Pin Layout — Octal
1
2
3
4
5
6
7
8
1
Screen Grid (Grid No. 2)
2
Heater
3
Plate
4
References
https://frank.pocnet.net/sheets/049/7/7027A.pdf
200
V
Max Grid Resistor
Max Grid Resistor (fixed bias)
0.1
MΩ
Typical Operating
Anode Voltage (typical)
Plate Voltage
250
V
Screen Voltage (typical)
Screen Voltage
250
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-14
V
Anode Current
Plate Current
72
mA
Screen Current
Screen Current
5
mA
Anode Resistance
Plate Resistance (approx.)
22,500
Ω
Transconductance
Transconductance
6
mA/V
Capacitances
Grid-to-Plate Capacitance
Grid-to-Plate Capacitance
1.5
pF
Input Capacitance
Input Capacitance
10
pF
Output Capacitance
Output Capacitance
7.5
pF
Screen Grid (Grid No. 2)
5
Control Grid (Grid No. 1)
6
Control Grid (Grid No. 1)
7
Heater
8
Cathode + Grid No. 3