GM70

Classic Soviet directly heated low-mu audio power triode. Approximately 125 W plate dissipation, low amplification factor, and 1.5 kV capability provide substantial low-frequency output from a carbonized-tungsten filament.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: J4
Base pins: 0
Nominal heater: 20 V / 3 A

Description

The GM70 is a high-power directly heated low-frequency triode.

Socket description

Jumbo 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: J4
Base pins: 0
Nominal heater voltage: 20 V
Nominal heater current: 3 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Transconductance: 0.006 S
Amplification factor: 6.7
Max plate voltage: 1500 V
Max plate dissipation: 125 W

Promoted-field audit performed from English ratings/characteristics; detailed electrical values retained in parameter table.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

195X Russian

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater voltage
19 to 20 V
AC or DC
Plate voltage
1500 V
DC
Plate dissipation
125 W
Continuous
Plate dissipation, 1 minute
150 W
Short duration

Characteristics

Heater current
3 A
Nominal
Cathode current
800 mA
Minimum; Ua=180V, Vg=180V
Transconductance
6 mA/V
Published condition
Amplification factor
6.7
Published condition
Insulation resistance
20 MOhm
Minimum
Inverse grid current
4 uA
Maximum
Grid-plate capacitance
12 pF
Approximate
Grid-cathode capacitance
8 pF
Approximate
Plate-cathode capacitance
4 pF
Approximate
Lifetime
1000 h
Published value

Data set 02

1968 Electronintorg

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

power
70 Hz
The M-70 triode is used as a low-frequency power
Cathode: directly heated, carbonized tungsten. oS ™ [1]
3
Cathode: directly heated, carbonized tungsten. oS ™ 3, 2—«kavop; 5 — aHog;
Cathode: directly heated, carbonized tungsten. oS ™ [2]
2
Cathode: directly heated, carbonized tungsten. oS ™ 3, 2—«kavop; 5 — aHog;
Cathode: directly heated, carbonized tungsten. oS ™ [3]
5
Cathode: directly heated, carbonized tungsten. oS ™ 3, 2—«kavop; 5 — aHog;
anode [1]
32
u i 3,2~ pathode; 5 - anode;
anode [2]
5
u i 3,2~ pathode; 5 - anode;
grid [1]
185
Height: at most 185 mm. 1 wjfﬂ,if ] LEA] 7 - grid
grid [2]
1
Height: at most 185 mm. 1 wjfﬂ,if ] LEA] 7 - grid
grid [3]
7
Height: at most 185 mm. 1 wjfﬂ,if ] LEA] 7 - grid
temperature,°C [1]
-10 C
. ... —-10—-+55 Ambient temperature,°C ... ................... -10 +55
temperature,°C [2]
55 C
. ... —-10—-+55 Ambient temperature,°C ... ................... -10 +55
temperature,°C [3]
-10 C
. ... —-10—-+55 Ambient temperature,°C ... ................... -10 +55
temperature,°C [4]
55 C
. ... —-10—-+55 Ambient temperature,°C ... ................... -10 +55
voltage
600 uS
Mutual conductance (at anode voltage 600 V,
current [1]
160 mA
anode current 160-260 mA), mA/V ... ... .. .. .. .. 4.6-7.2
current [2]
-260 mA
anode current 160-260 mA), mA/V ... ... .. .. .. .. 4.6-7.2
current [3]
4.6 mA
anode current 160-260 mA), mA/V ... ... .. .. .. .. 4.6-7.2
current [4]
-7.2 mA
anode current 160-260 mA), mA/V ... ... .. .. .. .. 4.6-7.2
voltage [1]
1.2 kV
Gain coefficient (at anode voltage 1.2—1kV,
voltage [2]
-1 kV
Gain coefficient (at anode voltage 1.2—1kV,
voltage [1]
-200 V
at grid voltage —200 V,atmost .. ......... ... 80
voltage [2]
80 V
at grid voltage —200 V,atmost .. ......... ... 80
input [1]
5
input . ... 5-11
input [2]
-11
input . ... 5-11
output [1]
3
output ... 3-6
output [2]
-6
output ... 3-6
dissipation, W [1]
125 W
PaccenBaemast MOWHOCTbL aHogom, BT .. ... ... .. 125 Anode dissipation, W . ... ... ... .. ... ... .. .. 125
dissipation, W [2]
125 W
PaccenBaemast MOWHOCTbL aHogom, BT .. ... ... .. 125 Anode dissipation, W . ... ... ... .. ... ... .. .. 125
grid vomage Uy [1]
500
500 yd tage Uy 1s squal 1o grid vomage Uy
grid vomage Uy [2]
1
500 yd tage Uy 1s squal 1o grid vomage Uy
grid vomage Uy [3]
1
500 yd tage Uy 1s squal 1o grid vomage Uy
Anode Characteristic Curves: U, =
20
Averaged Anode Characteristic Curves: U, =20V |
grid; A ,/
5
iz an%de-grid; A ,/ 5 i