1. Vintage Tubes & Sockets Audio For Sale
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  3. CUNNINGHAM CX-220

CUNNINGHAM CX-220 Vacuum Tube Power Triode Radios 1920S

Cx-220 Cunningham 1 Vacuum Tube Rare 1920s Power Triode For Vintage Radios

( Brand: Cunningham ), ( Manufacturer Part Number: CX-220 ), ( Model: CX-220 AKA 20 ), ( Type: Cx-220 Vacuum Tube ), ( Staus: Strong Tv-7 Tests ), ( Application: Vintage Radios ), ( Country Of Origin: United States )

Review CUNNINGHAM Vacuum Tube Rare 1920s Power Triode Vintage Radios

The **Cunningham CX-220** is a meticulously crafted, early 20th-century power triode vacuum tube designed for high-performance radio amplification and transmission applications, embodying the engineering ingenuity of the 1920s. This rare and highly sought-after tube represents the pinnacle of early radio technology, featuring a robust **glass envelope** with a **thoriated tungsten filament** that emits electrons through a precisely spaced **triode configuration** comprising a control grid, a screen grid, and a massive **cylindrical anode (plate)** all engineered to deliver exceptional power output and efficiency. Measuring approximately **5 inches in length** with a diameter of around **3 inches**, the CX-220 s physical structure is both elegant and functional, with a **bayonet-style base** that ensures secure mounting in vintage radio chassis. Inside, the tube houses a **high-vacuum environment**, free from modern gas-fill innovations, which allows for cleaner, more stable electron flow while demanding meticulous alignment and power supply regulation to prevent arcing or filament burnout. Originally manufactured by **Cunningham Radio Corporation**, a pioneering firm in the early days of wireless communication, this tube was specifically intended for **high-power broadcast transmitters, marine radios, and early amateur radio setups**, where its ability to handle **100 to 200 watts of RF power** made it indispensable. The CX-220 s **triode design** without the complexity of later tetrodes or pentodes simplifies circuit integration while maintaining impressive gain and linearity, making it ideal for **class-A and class-B amplification stages** where fidelity and reliability were paramount. Today, collectors and restorers prize the CX-220 for its **historical significance**, its **aesthetic appeal**, and its **unmatched performance** in vintage radio systems, offering enthusiasts a tangible link to the golden age of wireless technology. Properly restored examples, with intact filaments and clear glass, command high prices among hobbyists, while even used specimens remain valuable for those seeking to revive or enhance classic radio equipment.

Buying a **Cunningham CX-220 vacuum tube**, a 1920s-era power triode designed for early radio amplifiers and transmitters, can be a fascinating and rewarding endeavor for hobbyists, restorers, or collectors. However, it comes with distinct advantages and challenges that should be carefully considered before making a purchase.

### **Pros of Owning a Cunningham CX-220**

1. **Historical Significance** The CX-220 is a relic of early radio technology, dating back to the 1920s, when vacuum tubes were the foundation of wireless communication. Owning one connects you to the golden age of radio experimentation and innovation.

2. **Rarity and Collectibility** Original, unused CX-220 tubes are extremely rare, making them valuable to collectors. Even restored or functional examples can be sought-after pieces in vintage electronics circles.

3. **Technical Interest** Studying and operating a tube like the CX-220 provides insight into early amplifier design, power handling, and the limitations of pre-WWII tube technology. It s a great learning tool for those interested in radio history.

4. **Potential for Restoration and Repair** If the tube is damaged or non-functional, restoring it can be a rewarding DIY project. Many early tubes can be revived with proper cleaning, degassing, and replacement of internal components.

5. **Aesthetic and Curiosity Value** The tube s large size, glass construction, and historical appearance make it a striking addition to a radio or electronics museum display.

6. **Compatibility with Early Radio Circuits** The CX-220 was designed for high-power applications in early transmitters and amplifiers, making it useful for restoring or building vintage radio setups.

7. **Hobbyist Appeal** Enthusiasts of retro technology, ham radio, and analog electronics often seek out such components to experiment with or incorporate into custom builds.

### **Cons of Owning a Cunningham CX-220**

1. **Extreme Fragility** Glass-enclosed tubes from the 1920s are highly susceptible to breakage. Even minor handling errors (e.g., dropping, thermal shock) can shatter the bulb. Modern tubes are far more durable by comparison.

2. **Limited Availability and High Cost** Finding a functional or even usable CX-220 is difficult. Prices for original, working examples can be prohibitively expensive, often exceeding $100 $300 or more, depending on condition.

3. **Maintenance and Care Requirements** Unlike modern tubes, early power triodes require careful handling to prevent contamination (e.g., oil, dust, or moisture) that can degrade performance or render them useless. Storage in a clean, dry environment is essential.

4. **Power and Efficiency Limitations** The CX-220 was designed for lower power standards by today s metrics. It may not handle modern high-power demands efficiently, and its glass construction makes it less suitable for high-voltage applications without risk.

5. **Difficulty in Testing and Replacement** If the tube fails, finding a direct replacement is nearly impossible. Modern equivalents (e.g., 2A3, 426A) may not match performance, and rebuilding the tube is a complex process requiring specialized knowledge.

6. **Safety Risks** Early tubes often lack modern safety features. Improper handling of high voltages or improper degassing can pose electrical hazards, especially for inexperienced users.

7. **Limited Practical Use** While the CX-220 has historical value, its application in modern electronics is severely limited. Most hobbyists today use it purely for display or educational purposes rather than functional use.

8. **Ethical and Preservation Concerns** Some collectors argue that removing tubes from original equipment (if found in antique radios) may be unethical, as it can degrade the historical integrity of the device.

### **Conclusion and Recommendation**

The Cunningham CX-220 is a **highly specialized and niche** component best suited for collectors, historians, or hobbyists with a deep interest in vintage electronics. If you are drawn to it for **educational, aesthetic, or historical reasons**, it can be a fascinating addition to your collection provided you are prepared for its fragility, rarity, and limited practical utility.

However, if you are looking for a **functional, reliable, or modern-use tube**, the CX-220 is not the best choice. Modern alternatives (e.g., 2A3, 426A, or even modern power triodes) offer better performance, durability, and availability at a fraction of the cost.

**Final Recommendation:**

- **Buy it if:** You are a collector, restorer, or enthusiast who values historical artifacts and is willing to handle its fragility with care. Consider it as a display piece or a learning tool rather than a functional component.

- **Avoid it if:** You need a reliable, easy-to-source tube for active radio projects. In that case, modern or mid-century replacements will serve you far better.

For those serious about acquiring one, always **verify its condition** (look for cracks, blackened filaments, or internal damage) and **handle it with extreme care** to avoid breakage. If possible, consult with experienced tube collectors or restorers before purchasing.

Details:

6C4 1 Cunningham CX-220 aka 20 Vacuum Tube. Hickok TV-7D/U test reads 22. A reading of 13 is the minimum recommended. Vintage 1930s Power Triode.

part #: cx220 prices

  • $75.00-$100.00

specifications tubesocketvintagego:

  • brand: Cunningham
  • mpn: Cx-220
  • model: Cx-220 Aka 20
  • type: Cx-220 Vacuum Tube
  • staus: Strong Tv-7 Tests
  • application: Vintage Radios
  • country of origin: United States

payments tubesocketvintagego:

  • credit card: Visa
  • other
  • wallet: Paypal

general tubesocketvintagego:

  • condition: Used
  • Vintage Audio Video > Vintage Parts Accessories > Vintage Tubes Tube Sockets

offer tubesocketvintagego:

  • quantity: 1
  • availability: In Stock
  • sold: 0
  • started: March 25, 2026
  • options: Ship-to-home

returns tubesocketvintagego:

  • method: Money back
  • policy: Returns Accepted
  • paid by: Seller
  • time: 30 Days

seller tubesocketvintagego:

  • rating: 99.8%
  • city: Entiat, Washington
  • # reviews: 21305

shipping tubesocketvintagego:

  • class: Standard
  • service: USPS Ground Advantage
  • cost: $6.50
  • transit: 2-6 Days
  • carrier: USPS
  • type: Fixed
type: cx-220 vacuum tube, staus: strong tv-7 tests, application: vintage radios, country of origin: united states,
category: electronics > vintage audio video > vintage parts accessories > vintage tubes tube sockets, sku: 11095446776373853,
Cunningham CX-220 Is Similar To:
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3 offers $75.00–$100.00 USD
  • Used. Offer #1 priced at $100.00 + $6.99 shipping estimate = $106.99* total. Tight base. This tube still has it's original paper label on it's glass.+$6.99 shipping
  • Used. Offer #2 priced at $75.00 + $6.75 shipping estimate = $81.75* total. This tube is from 1930 s USA production. The 220 (aka 20) is a power triode.+$6.75 shipping
  • Used. Offer #3 priced at $75.00 + $7.00 shipping estimate = $82.00* total. +$7.00 shipping

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