Rare Triode1930’s DET25/VT25 10E/7312 New in brown Military Box

DET25 / VT25 (10E/7312) Vacuum Tube – New in Original Brown Military Box

Special VT25

Manufacturing Date Code 7th May 1936

This is the Rare British DET25 transmitting triode,
Extensive use in Royal Air Force (RAF) transmitters and radio communication sets throughout the 1930s and World War II era  .

Designed for operation up to 1250V, making it far more robust than the American VT25 / Type 10 equivalents. Electrically compatible with circuits using VT25 but with heavier-duty construction and prized for its performance and durability. Supplied new in original brown military box (NOS).

Intended for High-End Audio Amplification
This rare British DET25 is a cornerstone component for ambitious amplifier projects, particularly:
High-Power Single-Ended Triode (SET) Amplifiers: Its unique 1250V anode rating allows builders to achieve higher output power without sacrificing the legendary SET sound quality.
Boutique and DIY Builds: Ideal for audio enthusiasts and engineers designing custom, no-compromise amplifiers from the ground up.
Driving Efficient Speakers: Perfect for use with high-efficiency horn, full-range, or classic monitor speakers.
This tube is sold to experienced builders and collectors who understand its specific requirements and exceptional potential.”
This language clearly signals that the tube is for a specialized, knowledgeable market, which justifies its value and ensures it goes to a buyer who will truly appreciate it.

This DET25 vacuum tube is British-made, manufactured by M.O.V. (Marconi-Osram Valve Co.), a company closely associated with GEC in the 1930s. These companies jointly produced high-quality transmitting tubes for British military. and industrial use.

Use of DET25 Triode Tubes in British Royal Air Force Transmitters
The DET25 triode, a ruggedized and high-voltage capable directly-heated power triode, was a key component in various British military radio transmitter designs during the late 1930s and World War II period. Its robust construction and ability to operate at higher plate voltages made it invaluable for reliable high-frequency and medium-frequency radio communications.

 

Description:
Offered here is a genuine DET25 / VT25 (10E/7312) vacuum tube, supplied with new old stock (NOS) in its original brown military packaging. A highly regarded transmitting/triode tube, the VT25 is prized by audiophiles, collectors, and tube enthusiasts for its warm, detailed sound and vintage authenticity.
Type/Designation: DET25 / VT25 (Equivalent to 10E/7312)
Condition: New Old Stock (NOS) – unused, stored in original box
Packaging: Original military brown storage box
Applications: Audio amplifiers, transmitters, vintage military/industrial equipment
Collector’s Note: Rare in unused condition with intact original packaging

⚡ Voltage / Operating Spec Differences
VT25 (USA “Type 10” triode):
Typical max plate voltage: ~450–600 V
Plate dissipation around 10–12W
Used in audio and low-power transmitter circuits
DET25 (UK version, GEC/Osram):
Designed as a transmitting triode, ruggedized
Max anode (plate) voltage: around 1250 V (much higher than VT25/10)
Much stronger build, larger spacing, very robust
Favored in military/industrial gear where high voltages were needed

✅ What this means
DET25 is not just a “copy” of the VT25 — it’s effectively a more heavy-duty transmitter version.
Electrically, it can substitute in most VT25 (Type 10) circuits, but it was rated for much higher voltage handling for transmitting/military duty.
This is why the physical structure looks different — bigger anode, thicker construction, more insulation spacing to withstand 1250V vs ~450–600V of the American VT25.
Physical / Structural Differences
VT25 (USA):
Slimmer glass bulb; smaller plate; typical “American DHT look”
Intended mostly for audio and moderate RF transmitter duty
Cannot safely handle >600 V for long durations
DET25 (UK):
Heavier, more rugged internal structure; wider plate spacing
Built for transmitter service where >1000 V was common
More robust with military specification packaging
Can safely operate at voltages that would destroy a U.S. VT25

In Plain Words
Electrically similar in low‑to‑mid voltage applications (~350–450V circuits) → interchangeable.
DET25 survives in very high voltage circuits (up to 1250V) where the regular VT25 cannot.
Many audiophiles and collectors prize the DET25 for its reliability, rare build, and perceived improvement in sound in high‑end triode amplifiers.

✅ So the DET25 is not simply a rebranded VT25 — it’s a beefed‑up, higher rated variant of the same “Type 10 triode family.”

About Us

We specialized in thoroughly tested

and screened quality vacuum tubes.

We have various type of valves and tubes testers

– Amplitrex AT1000 Advance Digital Tube Tester,

– Hickok 752a tube tester,

– AVO Type 160

We have been in the valve and tube Business Since 1970’s.

Previously we were better Known as a Wholesaler,

but recently, We are offering more retail items.

All item are tested and guaranteed, supplied

We have Approximately 3,00,000 Valve and Tubes Stock

Custom duties and taxes is the responsibility of the buyer in their country

If the address is away from city, town there is extended area surcharge, So

Kindly confirm your  orders  before making checkout.

PLEASE CONTACT US IF YOU REQUIRE FURTHER INFORMATION ABOUT  THIS TUBE / VALVE.