COLLINS 409M-4 Radio Power Supply Military Tube High Voltage

( Brand: Collins ), ( Manufacturer Part Number: 409M-4 ), ( Type: Power Supply )

Review COLLINS Vintage Radio Power Supply Military Surplus Tube High Voltage

The **Collins 409M-4 Radio Power Supply** is a robust, high-performance military-grade power supply unit designed to deliver precise and reliable voltage regulation for vintage and modern tube-based radio equipment, particularly those operating in demanding environments. Originally developed for military and aerospace applications, this unit exemplifies engineering excellence with its rugged construction, ensuring durability under extreme conditions such as high altitudes, temperature fluctuations, and mechanical stress. The 409M-4 is a high-voltage power supply, capable of generating stable and clean DC output essential for driving high-power vacuum tubes, such as those found in transmitters, receivers, and other critical radio systems. Its design incorporates advanced circuitry to minimize ripple and noise, providing the high-quality power necessary for optimal tube performance and longevity.

This power supply features a modular and versatile architecture, allowing it to interface seamlessly with a wide range of Collins and other military-grade radio equipment, including the iconic **409M series** and other high-end tube radios. The unit is equipped with robust transformers and precision rectifiers, often utilizing selenium or mercury-vapor diodes for their reliability and efficiency in high-voltage applications. The 409M-4 s internal components are meticulously shielded to prevent electromagnetic interference (EMI), making it ideal for use in environments where signal integrity is paramount. Its robust chassis, typically constructed from heavy-duty metal, provides both mechanical protection and thermal dissipation, ensuring consistent operation even under prolonged use.

One of the standout features of the Collins 409M-4 is its adaptability, often including adjustable voltage outputs to accommodate different tube requirements. This flexibility makes it a valuable asset for both restoration projects and modern ham radio enthusiasts seeking to replicate vintage military radio setups. The unit s design also incorporates safety mechanisms, such as over-voltage protection and thermal cutouts, to safeguard both the equipment and the operator. While primarily intended for military applications, its reliability and performance have made it a favored choice among collectors, restorers, and radio hobbyists who demand nothing less than the highest standards of quality and precision.

For those seeking to integrate this power supply into a complete radio system, the Collins 409M-4 is often paired with other components from the same series, such as the **409M-1 receiver** or **409M-2 transmitter**, creating a cohesive and high-performance setup. Its legacy in military communications underscores its importance as both a functional tool and a piece of historical engineering. Whether used in a restored vintage radio station, a dedicated ham shack, or as part of a specialized test setup, the Collins 409M-4 remains a testament to the enduring legacy of Collins Radio s commitment to excellence in radio technology.

### **Pros and Cons of buying a Collins 409M-4 Radio Power Supply (Military Tube, High Voltage)**

1. **High Reliability and Durability** The Collins 409M-4 is a well-known military-grade power supply designed for long-term use in harsh environments. Its robust construction ensures stability under demanding conditions.

2. **High Voltage Output** Capable of delivering high voltage (typically 400V 1000V depending on configuration), making it suitable for powering high-voltage tube amplifiers, transmitters, and vintage radio equipment.

3. **Compatibility with Tube Gear** Designed for use with vacuum tubes (such as those in vintage broadcast transmitters, tube amplifiers, and early radio systems), it provides the necessary regulated power for optimal performance.

4. **Military-Grade Components** Built with high-quality, long-lasting parts, reducing the risk of sudden failures. This makes it ideal for both amateur radio and professional applications.

5. **Adjustable and Regulated Output** Many versions of the 409M-4 feature adjustable voltage and current outputs, allowing fine-tuning for different tube setups.

6. **Low Noise and Stable Power** Designed to minimize electrical noise, which is crucial for sensitive radio transmissions and audio applications.

7. **Repairability and Availability of Parts** Due to its military heritage, replacement parts and schematics are often available, making repairs easier than with some modern power supplies.

8. **Legacy System Integration** If you work with vintage or military-grade radio equipment, this power supply is a natural fit, ensuring compatibility without the need for adapters.

9. **Long Lifespan** Properly maintained, these units can last decades, making them a cost-effective investment over time.

10. **Historical and Collectible Value** For enthusiasts, owning a Collins 409M-4 is a nod to early radio technology, adding both functional and nostalgic value.

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1. **High Cost** Due to its military-grade build and rarity, the Collins 409M-4 can be expensive, especially if sourced from reputable sellers or restored units.

2. **Complexity in Operation** Requires some technical knowledge to set up, adjust, and troubleshoot. Beginners may struggle with calibration and safety considerations.

3. **Safety Risks** High-voltage power supplies pose a serious electrical hazard. Improper handling can lead to shock, arcing, or equipment damage.

4. **Limited Modern Compatibility** Not designed for modern solid-state equipment. It is strictly for tube-based systems, which may limit its usefulness in contemporary setups.

5. **Maintenance Requirements** Like all high-voltage equipment, it requires periodic inspection for wear, insulation degradation, and component aging to prevent failures.

6. **Weight and Bulk** Military-grade units are often heavy and large, making them less portable than modern power supplies.

7. **Finding a Working Unit** Many 409M-4 units are either in poor condition or require restoration. Sourcing a fully functional one can be challenging and time-consuming.

8. **Power Supply Limitations** Some versions may not handle high-current loads well, requiring additional components (such as transformers or regulators) for certain applications.

9. **Depreciation Risk** While vintage equipment can appreciate, some collectors may prefer newer, more efficient alternatives, potentially affecting resale value.

10. **Learning Curve for Repairs** If the unit fails, repairs may require specialized knowledge or skilled technicians, increasing downtime and cost.

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The Collins 409M-4 is a **highly capable, durable, and reliable** power supply for tube-based radio and audio applications, particularly for those working with vintage or military-grade equipment. Its strengths lie in its **stability, adjustability, and longevity**, making it a valuable tool for enthusiasts and professionals who prioritize performance over modern convenience.

However, its **high cost, complexity, and safety risks** make it less suitable for casual users or those working with solid-state systems. It is best suited for **experienced operators, collectors, or those restoring classic radio equipment** who are willing to invest time in learning and maintaining the unit.

If you need a **modern, user-friendly, and versatile** power supply, alternatives like high-quality regulated bench power supplies may be more practical. But for **purists, historians, or dedicated tube enthusiasts**, the Collins 409M-4 remains a **premium choice** provided you are prepared for its demands.

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- **Buy if:** You are restoring or operating **vintage tube transmitters, military radios, or high-end tube amplifiers**, and you have the technical expertise to handle high-voltage equipment safely. If you value **reliability, adjustability, and historical significance** over modern convenience.

- **Avoid if:** You are a beginner, work primarily with **solid-state equipment**, or need a **portable, easy-to-use** power supply. If budget constraints or safety concerns make high-voltage maintenance impractical.

- **Alternative Considerations:** For modern tube applications, look into **high-quality regulated power supplies** (e.g., from brands like **Kepco, Astec, or custom-built units**). For military-grade needs, ensure the unit is **fully tested and restored** before use.

Ultimately, the Collins 409M-4 is a **specialized tool** one that rewards those who understand and appreciate its strengths. For most everyday use, however, modern alternatives may be more practical.

Details:

Tube rectification: RCA 6X5GT visible in photos. Military/ham radio collectors. For sale: Rare vintage Collins Radio Company power supply Type 409M-4 serial 21769, a high- voltage linear unit from the 1950s 1960s Cold War era. Ships from Newcastle, OK.

Untested/as-is high voltage do not power without expertise/safety precautions. Rear: 3-amp fuse holder, military-style connectors. Well-boxed with foam/bubble wrap. T402/T401, reactors/chokes L401, rectifier/filter sections with specs like 6 Henry's, 150 DC amps max, 100 ohms resistance at 75 C, 2500V test voltage .

Perfect for: Collins radio restorers pairs with military sets like ARC-series or TCS variants. Heavy-duty Chicago Transformer iron: Multiple transformers Grab this piece of radio history. Tubes look original, internals appear intact from photos.

Collins was a top USA military contractor for aviation/ground/shipboard radios this likely powered transmitters/receivers in commas systems. Display in vintage electronics collection. Highlights: Rugged gray military enclosure with hinged lid, ventilation, and multi-pin power input connector. Condition: Good vintage surplus complete, no missing major parts, patina/rust/dust from age normal for military gear, labels readable.

part #: 409m4 prices

• $69.99-$1000.00

specifications hamamateuradio:

• brand: Collins
• mpn: 409m-4
• type: Power Supply

general hamamateuradio:

• condition: Used
• Radio Communication > Ham, Amateur Radio > Ham Radio Amplifiers

returns hamamateuradio:

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

seller hamamateuradio:

• city: Oklahoma City, Oklahoma
• # reviews: 1161
• rating: 99.8%

offer hamamateuradio:

• options: Ship-to-home
• availability: In Stock
• started: February 24, 2026
• quantity: 1
• sold: 0

shipping hamamateuradio:

• carrier: USPS
• transit: 3-8 Days
• type: Fixed
• class: Standard
• cost: $0.00
• service: USPS Ground Advantage

payments hamamateuradio:

• credit card: Mastercard
• other
• wallet: Google-pay

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