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L410 tube: datasheets and technical data
Explore available pinout, electrical data and related types for the L410 vacuum tube.
The L410 documented in the Marconi leaflet is a directly heated triode for transformer-coupled audio amplification. The manufacturer also permits detector service when preceded by one or more high-frequency stages. The catalogue page presents it alongside P410 and P415 output valves, explicitly assigning loudspeaker power applications to those types; the main role specified for L410 is low-frequency amplification.
The Marconi approximate-data panel gives 4 V maximum filament voltage, 0.1 A filament current and 150 V maximum anode voltage. At 100 V anode voltage and zero grid voltage it specifies amplification factor 15, internal impedance 8,500 Ω and mutual conductance 1.76 mA/V. The curves show anode-current variation with grid voltage and include grid current. These figures remain tied to the operating point and brand described in the document, rather than becoming generic data for all valves sharing the designation.
Our sources describe a preserved British specimen also marked NR15A and Admiralty Pattern 7404A, with M-OV identification and L410 on the top of the bulb. This is a detail of its history and markings. The B4 base has four pins for anode, grid and the two filament ends. That specimen is described as 46 mm in diameter and 88 mm tall excluding pins. A secondary table also gives 150 V anode voltage, −4.5 V bias and 3.9 mA current: a point distinct from the Marconi leaflet’s approximate data at 100 V.
Tube images
Pinout and connections
Base: 4A - Europe 4-Pin B4 (Eu A, E, ) 1914 (Codex=Eo) (4 pin)
| Pin | Function |
|---|---|
| 1 | a |
| 2 | g1 |
| 3 | f |
| 4 | f |
Electrical data
Filament
- Filament voltage Vh
- 4 V
- Filament current Ih
- 0.15 A
Datasheet PDF
| Language | Pages | Manufacturer | |
|---|---|---|---|
| L410.pdf | en | 1 | Marconi Italiana |
EL84 ECC83 12AX7 EL34 6L6GC 300B KT88 GZ34
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