Back to previous page Back to Wumpus´s Old Radio World homepage Diese Seite in deutsch

Last update 06/05/2009. Online since 1996

Tuning Eye Tuning indicator tubes for old-time radio sets

Display image variants: Used termes for such tubes: tuning indicator tube. Tuning indicator valve. Magic Eye. Eye tube. Electron-ray indicator tube. Fan-shaped display tube. Glowing tube. And so on.

Soon after introduction of the broadcasting in 1923 the industry offered support for best tuning of the receivers on the exact station frequency. First these were glowing tubes, pure optical brightness indicators, pointer measurement instruments (also shadow pointers) and light bulbs. About 1935 the vacuum tubes came as fluorescent screens on the market. First as round 'magic eyes' on the top of the bulp. (e.g., AM1,), then as fan-type side screens and at last as rectangular band screens on the side of the bulps. For a greater indication range two level types were constructed (e.g., EM4). There were also systems with not only indicator function, but also with integrated amplifiers (e.g., EFM11). Multiple displays for more complicated processes were designed (e.g., EMM803) and also, in addition tubes for switch state signal indication (e.g., EAM86, for stereo state).

Here some examples:

Manufactures
Tube type
Click on photos
Remarks
Telefunken 
 

AM1 
AM1

First German "magic eye". Year of construction 1937 (1936). Not used in larger quantities. The industrie offered soon the better type AM2.

Telefunken


AM2

Schema AM2

Magic Eye

Valvo

 
DM 71 
"Magic line, key hole indicator tube", subminature tube for battery receivers, portable tape recorders.
Valvo


EAM86

Duo display with compact rectangular screen. 2 systems, one for field strenght indication, the other for rectifying (example).

Telefunken

EFM11

Magic Eye - type. Including a pentode for r.f. and n.f. preamplifiers.

Miniwatt

EM1
Magic Eye - type.
Telefunken.

C/EM2

Magic Eye - type. for use in C-series heater circuits of AC/DC sets and for parallel heated 6.3 volts circuits of AC sets.

 

Valvo

EM4
Magic eye. 2 sensitivity levels
VEB Neuhaus

EM11 
Magic eye, 2 sensitivity levels. GDR
Valvo

EM34 
Magic eye, 2 sensitivity levels. GDR
Lorenz

EM71

Magic eye
Valvo

EM80
Fan shaped type on the the side of the glass bulb.
RFT

EM83 

GDR. Interesting tube. 2 Systems for variable use. Fan shaped type. For use as a normal indicator with both systems in parallel. Using different risistors in anode line, the result was a two level indicator, one system for low level signals, the other for medium and high level signals. Also suitable for ratio indication for best FM tuning.

Lorenz

EM 85
Fan shaped type
 
Valvo 

EM87
Rectangular screen on the the side of the glass bulb.
ITT Lorenz

EMM803 
2 Systems. 2 rectangular screens on the side of the glass bulb. One for field strenght. One for yes-no-indication (e.g. r.f. stereo on/off). Last constructed tuning indicator tube.
Koerting.

GB2207GW
Glow tube, rarity. Variable light line. 1934
Valvo

PM84
Tuning indicator. For type P in series heater circuits.
Valvo

UM4

Magic eye tuning indicator tube for AC/DC power lines. For type U in series heater circuits.

Valvo

UM11

Magic eye.Tuning indicator tube for AC/DC power lines. For type U in series heater circuits.

   

  • Short video clip: UM11.AVI ( 800 KB in AVI format.)
  • Short video clip: UM11.RM (90 KB. in RM format)
Valvo

UM80
Fan shaped screen tuning indicator tube for AC/DC power lines. For type U in series heater circuits.
Mazda

6AF7
Magic eye tuning indicator tube (tuning indicator valve). (England, UK)
RCA?

6E5

Worldwide first tuning indicator tube (Magic eye) 1935 (1934). USA

Osram

8JR312B 

 

Glow tube, rarity. Variable light line. 1934

 

List of tuning indocator tubes
(143 ubes)
  • AM1
  • AM2
  • AW6
  • ACME
  • A39A
  • C/EM2
  • DM21
  • DM70
  • DM71
  • DM160
  • E82M
  • EAM86
  • EFM1
  • EFM3
  • EFM11
  • EM1
  • EM3
  • EM4
  • EM5
  • EM11
  • EM31
  • EM33?
  • EM34
  • EM35
  • EM71
  • EM71a
  • EM72
  • EM80
  • EM81
  • EM83
  • EM84
  • EM84a
  • EM85
  • EM87
  • EM171
  • EM800
  • EM840
  • EMM801
  • EMM802?
  • EMM803
  • E7046
  • E7047
  • E7082
  • E82M
  • FT4
  • HM34
  • HM71
  • HM85
  • ME4
  • ME4S
  • ME6
  • ME6S
  • ME41
  • ME91
  • ME920
  • OM5
  • PM5
  • PM84
  • RV2,4A1
  • RV12A1
  • Tunograph
  • TV4
  • TV4A
  • TV6
  • UFM11
  • UM4
  • UM11
  • UM34
  • UM35
  • UM40
  • UM80
  • UM81
  • UM83
  • UM84
  • UM85
  • UM171
  • VFT4
  • VFT6
  • VME4
  • VT98
  • VT138
  • VT215
  • Y61
  • Y62
  • Y63
  • Y64
  • Y65
  • Y73
  • Y61/3
  • Y119
  • Y62/4
  • 1M3
  • 1M90
  • 1N3
  • 2E5
  • 2G5
  • 41ME
  • 4FG6
  • 6AB5
  • 6AD6
  • 6AF6
  • 6AF7
  • 6AL7
  • 6BR5
  • 6CD7
  • 6DA5
  • 6DH7
  • 6DL7

  • 6DU6
  • 6E5
  • 6E5C
  • 6E5M (J)apan
  • 6EG5
  • 6FG6
  • 6FG8
  • 6G5
  • 6G-E7 (J)
  • 6GX8
  • 6H5
  • 6HU6
  • 6M-DE1 (J)
  • 6M-E2 (J)
  • 6M-E4 (J)
  • 6ME4
  • 6M-E5 (J)
  • 6M-E10 (J)
  • 6M1
  • 6M2
  • 6M40
  • 6N5
  • 6S5
  • 6T5
  • 6U5
  • 10E/305
  • 12CD7
  • 12DH7
  • 12FG6
  • 19BR5
  • 19DA5
  • 19DH7
  • 1629
  • 4677
  • 4678
  • 5624
  • 6977