06-10-2016, 08:12 PM
(This post was last modified: 06-10-2016, 08:19 PM by Mike Watterson.)
1e4a-v is offered as a DM70 / DM71 alternative.
It's only a similar function, less similar than Russian iv15 and European DM160 VFD miniature indicators, which are not particuarly compatible. iv15 is about 0.6V filament.
Search 1E4A magic eye on ebay.
Vf 1.0 V, If about 25mA
Va 150 V max, Ia max, about 1.5mA
Vg -0.25 ... -7.0 (Full to Off)
It's a lot smaller!
1E4A-B (1e4a-v) Russian Battery Magic Eye
I spotted this while looking for the Russian replacement of an EM80/EM81. It was advertised as being for similar use to the DM70. The DM70 is a simple triode with a coated plate rather than the normal magic eye which has a separate triode driving a small CRT (grid coupled to cathode) deflection electrode. The DM70 has a filamentary 1.4V cathode (25mA) and a solid grid plate with a cut out “exclamation” mark “!”. The bar varies with grid voltage due to varied width of cut out and the angle of the filament. It works because of the angled filament and cut-out, otherwise it would only vary in brightness like a DM160.
It is significantly smaller than the DM70 (which I believed was the smallest Magic Eye). Can it replace a DM70? Perhaps. But the DM70/DM71 isn't rare, unlike regular used Magic Eyes, an ex-equipment DM70 is usually quite bright.
Dimensions (DM70 vs. 1E4A-V)
Diameter: 9.7 mm vs. 6.6 mm
Wire diameter: 0.45 mm vs. 0.36 mm
Base: B8D (5.15 mm) vs 7 pin (3.4 mm). The B8D pin pitch is based on 9 pin positions, the sub-miniature 7 pin base is based on 8 positions. Diameters of pin circle are approximate.
These are interesting "NOS" for new construction, not DM70 / DM71 replacement as those are easy to get and it's not compatible, electrically or physically.
Radiomuseum http://www.radiomuseum.org/tubes/tube_1e4a-v.html
It's only a similar function, less similar than Russian iv15 and European DM160 VFD miniature indicators, which are not particuarly compatible. iv15 is about 0.6V filament.
Search 1E4A magic eye on ebay.
Vf 1.0 V, If about 25mA
Va 150 V max, Ia max, about 1.5mA
Vg -0.25 ... -7.0 (Full to Off)
It's a lot smaller!
1E4A-B (1e4a-v) Russian Battery Magic Eye
I spotted this while looking for the Russian replacement of an EM80/EM81. It was advertised as being for similar use to the DM70. The DM70 is a simple triode with a coated plate rather than the normal magic eye which has a separate triode driving a small CRT (grid coupled to cathode) deflection electrode. The DM70 has a filamentary 1.4V cathode (25mA) and a solid grid plate with a cut out “exclamation” mark “!”. The bar varies with grid voltage due to varied width of cut out and the angle of the filament. It works because of the angled filament and cut-out, otherwise it would only vary in brightness like a DM160.
It is significantly smaller than the DM70 (which I believed was the smallest Magic Eye). Can it replace a DM70? Perhaps. But the DM70/DM71 isn't rare, unlike regular used Magic Eyes, an ex-equipment DM70 is usually quite bright.
Dimensions (DM70 vs. 1E4A-V)
DM70 vs 1E4A-V
Nominal Length: (ex. Wires) 43 mm vs 33 mmDiameter: 9.7 mm vs. 6.6 mm
Wire diameter: 0.45 mm vs. 0.36 mm
Base: B8D (5.15 mm) vs 7 pin (3.4 mm). The B8D pin pitch is based on 9 pin positions, the sub-miniature 7 pin base is based on 8 positions. Diameters of pin circle are approximate.
These are interesting "NOS" for new construction, not DM70 / DM71 replacement as those are easy to get and it's not compatible, electrically or physically.
Radiomuseum http://www.radiomuseum.org/tubes/tube_1e4a-v.html