# 1E4A

> subminiature magic-eye indicator tube

**Wikidata**: [Q133361554](https://www.wikidata.org/wiki/Q133361554)  
**Source**: https://4ort.xyz/entity/1e4a

## Summary
The **1E4A** is a **subminiature magic-eye indicator tube**, a type of vacuum tube designed to visually display the amplitude of electronic signals. Introduced in **1960** by the **Moscow Electric Lamp Plant**, it was used in radio receivers and tape recorders to indicate signal strength or tuning status, offering a compact alternative to larger models like the EM34 and EM80.

## Key Facts
- **Type**: Subminiature magic-eye indicator tube (vacuum tube model)
- **Manufacturer**: Moscow Electric Lamp Plant (МЭЛЗ)
- **Year of introduction**: 1960
- **Classification**: Subclass of **magic eye tube** and **subminiature vacuum tube**
- **Designation**: Compliant with **Soviet vacuum tube standards**
- **Aliases**: Known as **1Е4А** (Cyrillic designation)
- **Function**: Provides a visual indication of electronic signal amplitude via a **luminophore and triode structure**
- **Applications**: Used in radio receivers, tape recorders, and tuning indicators
- **Physical traits**: Subminiature size, distinguishing it from larger models like EM34 and EM80
- **Developer**: Designed by **OKB-632** (a division of the Moscow Electric Lamp Plant)
- **Documentation**: Described in Russian at [http://www.155la3.ru/1e4av.htm](http://www.155la3.ru/1e4av.htm)
- **Country of origin**: Soviet Union
- **Related models**: EM34, EM80 (larger magic-eye tubes)
- **Inventor of magic-eye tubes**: **Allen B. DuMont** (1932, general class)
- **Wikimedia Commons category**: [1E4A](https://commons.wikimedia.org/wiki/Category:1E4A)
- **Radiomuseum ID**: 1e4a-v

## FAQs

### **What is the 1E4A used for?**
The **1E4A** is a **subminiature magic-eye tube** used to visually indicate the strength or amplitude of electronic signals, primarily in **radio receivers and tape recorders**. Its compact size made it suitable for devices with limited space, providing a clear tuning or signal-level display.

### **Who manufactured the 1E4A, and when was it introduced?**
The **1E4A** was manufactured by the **Moscow Electric Lamp Plant (МЭЛЗ)** in the **Soviet Union** and introduced in **1960**. It was developed by **OKB-632**, a design bureau associated with the plant.

### **How does the 1E4A differ from other magic-eye tubes?**
Unlike larger models such as the **EM34 and EM80**, the **1E4A** is a **subminiature version**, making it significantly smaller while retaining the same core function—a **luminophore and triode structure** that visually represents signal amplitude.

### **Where can I find technical details or images of the 1E4A?**
Technical documentation (in Russian) is available at [http://www.155la3.ru/1e4av.htm](http://www.155la3.ru/1e4av.htm). Images can be found in the **Wikimedia Commons category** for [1E4A](https://commons.wikimedia.org/wiki/Category:1E4A), including a photo of the tube labeled **1Е4А-В**.

### **What is the significance of the 1E4A in electronic display history?**
As a **subminiature magic-eye tube**, the **1E4A** represented an advancement in **compact electronic indicators**, allowing smaller devices to incorporate visual signal monitoring. It reflects the **Soviet Union’s contributions** to vacuum tube technology during the mid-20th century.

## Why It Matters
The **1E4A** holds importance as a **miniaturized evolution** of the magic-eye tube, a technology that revolutionized how users interacted with early electronic devices. Before digital displays, these tubes provided an **intuitive, analog visual feedback** mechanism for tuning radios or monitoring recording levels. The **1E4A’s subminiature design** made it possible to integrate such indicators into **space-constrained equipment**, extending the lifespan of vacuum tube technology even as transistors emerged. Its development by the **Moscow Electric Lamp Plant** also highlights the **Soviet Union’s role** in advancing electronic components during the Cold War era. While largely obsolete today, the **1E4A** remains a key artifact in the history of **electronic visualization** and **vacuum tube engineering**.

## Notable For
- **First subminiature magic-eye tube** in the Soviet Union (introduced in 1960)
- **Compact size**, distinguishing it from larger models like EM34 and EM80
- **Soviet manufacturing origin**, produced by the **Moscow Electric Lamp Plant (МЭЛЗ)**
- **Use of luminophore and triode structure** for visual signal amplitude indication
- **Compliance with Soviet vacuum tube designation standards**
- **Documented in Russian technical literature** (e.g., [http://www.155la3.ru/1e4av.htm](http://www.155la3.ru/1e4av.htm))
- **Inclusion in Wikimedia Commons** as a historical electronic component
- **Part of the broader magic-eye tube family**, invented by **Allen B. DuMont** in 1932

## Body

### **Origins and Development**
The **1E4A** is a **subminiature magic-eye indicator tube** developed in the **Soviet Union** and introduced in **1960**. It was manufactured by the **Moscow Electric Lamp Plant (МЭЛЗ)**, a key producer of vacuum tubes during the mid-20th century. The design was overseen by **OKB-632**, a specialized design bureau within the plant. Unlike earlier magic-eye tubes, which were larger (e.g., **EM34, EM80**), the **1E4A** was engineered for **compact applications**, making it suitable for smaller radio receivers and portable electronic devices.

### **Technical Specifications and Function**
The **1E4A** operates on the same principles as other magic-eye tubes but in a **miniaturized form**. It contains:
- A **luminophore** (fluorescent material) that emits light when struck by electrons.
- A **triode structure** that modulates the electron beam based on input signal amplitude.
- A **visual indicator** (typically a shadow or glowing segment) that changes in response to signal strength.

This design allows the tube to serve as a **tuning indicator** in radios or a **level meter** in tape recorders, providing users with real-time feedback on signal quality.

### **Relationship to the Magic-Eye Tube Class**
The **1E4A** belongs to the broader category of **magic-eye tubes**, which were invented by **Allen B. DuMont in 1932**. These tubes were widely used in **consumer electronics** from the 1930s to the 1970s, particularly in:
- **Radio receivers** (for tuning accuracy)
- **Tape recorders** (for recording level monitoring)
- **Test equipment** (for signal measurement)

The **1E4A** represents a **later, miniaturized iteration** of this technology, reflecting advancements in **vacuum tube miniaturization** during the 1950s–60s.

### **Manufacturing and Designation**
- **Manufacturer**: Moscow Electric Lamp Plant (МЭЛЗ)
- **Developer**: OKB-632 (a design bureau under МЭЛЗ)
- **Year of introduction**: 1960
- **Designation**: **1Е4А** (Cyrillic) / **1E4A** (Latin)
- **Compliance**: Follows **Soviet vacuum tube naming conventions**
- **Documentation**: Technical details are available in Russian at [http://www.155la3.ru/1e4av.htm](http://www.155la3.ru/1e4av.htm)

### **Applications and Use Cases**
The **1E4A** was primarily used in:
1. **Radio receivers** – As a **tuning indicator**, helping users adjust antennas or dials for optimal signal reception.
2. **Tape recorders** – As a **recording level meter**, ensuring proper audio input levels.
3. **Portable electronics** – Its **subminiature size** made it ideal for compact devices where larger tubes (e.g., EM80) would not fit.

### **Cultural and Historical Context**
The **1E4A** is part of a **larger technological lineage** that includes:
- **Early vacuum tube displays** (pre-digital era)
- **Soviet electronic engineering** (Cold War-era innovations)
- **Transition from analog to digital indicators** (as LEDs and LCDs later replaced magic-eye tubes)

While no longer in production, the **1E4A** remains a **collectible item** among vintage electronics enthusiasts and is documented in **online archives** such as **Wikimedia Commons** and the **Radiomuseum** database.

### **Comparisons with Other Magic-Eye Tubes**
| Model  | Year   | Size          | Notable Use Cases          |
|--------|--------|---------------|----------------------------|
| EM34   | 1930s  | Standard      | Early radio receivers      |
| EM80   | 1950s  | Standard      | High-end audio equipment   |
| **1E4A** | **1960** | **Subminiature** | Portable radios, compact devices |

The **1E4A’s** compact design set it apart, allowing integration into **smaller, more portable electronics**—a trend that aligned with the broader shift toward **miniaturization** in the 1960s.

### **Legacy and Preservation**
Today, the **1E4A** is preserved in:
- **Vintage electronics collections**
- **Online databases** (e.g., Radiomuseum, Wikimedia Commons)
- **Historical documentation** (Russian technical manuals)

Its existence highlights the **ingenuity of Soviet-era engineering** and the **evolution of electronic displays** before the digital revolution.