VT 52 WESTERN ELECTRIC Tested 97% matching HI-FI DHT WITH BOX

Western Electric VT-52Rare Vintage DHT Pair – Professionally Tested – 97% Ia Matching

32.0 mA / 33.0 mA – 97.0% Ia Matching – CD/P6 95% / 95%

For sale is a particularly interesting pair of Western Electric VT-52 directly heated power triodes, professionally tested using both a Metrix U61B valve analyser and an Elettrocostruzioni Chinaglia CD/P6 tester.

The two tubes are attractive examples of the classic VT-52 construction, with large clear glass envelopes, substantial internal structures and traditional four-pin bases.

Most importantly, they are in excellent electrical condition. The two tubes measured 32.0 mA and 33.0 mA against a Metrix reference value of 29.0 mA, while both independently measured 95% on the Chinaglia CD/P6 efficiency scale.

Exceptional Electrical Pair

BR5201: 32.0 mA – 110% of reference – CD/P6 95%

BR5202: 33.0 mA – 114% of reference – CD/P6 95%

Ia Matching: 97.0%

Average Ia: 32.5 mA – approximately 112% of reference

The absolute difference between the two tubes is only 1.0 mA, demonstrating excellent electrical consistency at the measured operating point.

Western Electric VT-52

The VT-52 is one of the most fascinating American directly heated power triodes from the classic vacuum-tube era.

Western Electric examples are particularly desirable among collectors and enthusiasts of early directly heated triodes, both for their historical importance and their use in specialised high-quality tube amplification.

This particular pair is especially interesting because the measurements show not only strong emission, but also very close electrical behaviour between the two tubes.

Slight Difference Between the Bases

As clearly shown in the photographs, the two tubes present a slight difference in the construction and external finish of their bases.

This difference mainly concerns the shape and finish of the lower base assemblies and is intentionally shown clearly in the listing photographs.

Both tubes are nevertheless Western Electric VT-52 four-pin directly heated triodes.

Apart from this small external difference, the pair is visually very coherent, with very similar glass envelopes and internal electrode structures.

More importantly, their electrical performance is remarkably close, with only 1.0 mA difference in plate current, resulting in an excellent 97.0% Ia matching value.

Important Note About the Military Boxes

The photographs also show two vintage U.S. Army Signal Corps VT-52 boxes.

These are genuine period VT-52 military boxes, but they are NOT the original boxes belonging to these exact two tubes.

The boxes carry the markings:

WESTERN ELECTRIC CO.

and

MFD. BY HYTRON CORP., SALEM, MASS., U.S.A.

The Hytron wording refers to the historical tubes originally supplied in those specific military boxes and does not identify the manufacturer of the two Western Electric VT-52 tubes offered in this listing.

The boxes are included as interesting period U.S. Army Signal Corps VT-52 accessories and are not represented as the original packaging for these particular tubes.

Identification and Test ResultsBR5201

• Western Electric VT-52
• Plate current: 32.0 mA
• Performance versus reference: 110%
• Chinaglia CD/P6 efficiency: 95%
• Result: EXCELLENT

BR5202

• Western Electric VT-52
• Plate current: 33.0 mA
• Performance versus reference: 114%
• Chinaglia CD/P6 efficiency: 95%
• Result: EXCELLENT

Professional Metrix U61B Test

Both tubes were professionally tested using a Metrix U61B valve analyser under the same operating conditions.

Reference operating point:

• Reference Ia: 29.0 mA
• Grid voltage Vg1: -43.5 V

Measured results:

• BR5201: 32.0 mA
• BR5202: 33.0 mA

Both tubes therefore test above the reference plate-current value.

97% Ia Matching

The measured plate currents are:

32.0 mA / 33.0 mA

Matching calculation:

32.0 / 33.0 × 100 = 97.0%

The average plate current of the pair is 32.5 mA, corresponding to approximately 112% of the 29.0 mA reference value.

The Ia spread relative to the average is only 3.1%.

These measurements document a strong and very closely matched pair at the measured operating point.

Chinaglia CD/P6 Efficiency Test

The electrical assessment was independently supported by a second test using an Elettrocostruzioni Chinaglia CD/P6.

Both tubes returned exactly the same efficiency reading:

BR5201: 95%

BR5202: 95%

This identical result provides an additional confirmation of the excellent electrical consistency of the pair.

Technical Specifications

• Manufacturer: Western Electric
• Designation: VT-52
• Quantity: 2 tubes
• Type: Directly heated power triode
• Base: 4-pin
• Reference Ia: 29.0 mA at Vg1 -43.5 V
• Measured Ia: 32.0 mA / 33.0 mA
• Performance vs. reference: 110% / 114%
• Ia Matching: 97.0%
• Ia spread vs. average: 3.1%
• Chinaglia CD/P6 efficiency: 95% / 95%
• gm: 2.00 mA/V
• Test equipment: Metrix U61B + Elettrocostruzioni Chinaglia CD/P6
• Identification codes: BR5201 / BR5202
• Accompanying boxes: Vintage U.S. Army Signal Corps VT-52 boxes, not original to these exact tubes
• Condition: Excellent cosmetic and electrical condition

The photographs show the exact two Western Electric VT-52 tubes offered for sale and document their glass envelopes, internal structures, bases, markings, military boxes and test results.

Shipping

The tubes will be packed with particular care using professional protective materials suitable for valuable vintage vacuum tubes.

Orders are normally dispatched within 1–2 business days after payment confirmation.

All shipments are fully tracked and handled by UPS, DHL or BRT, depending on destination, service availability and, whenever possible, the buyer’s preference.

The two tubes will be individually protected with shock-absorbing material and placed inside a rigid outer shipping box. The vintage military boxes will also be protected separately.

For orders with a value above €200, shipping is always insured.

Local pickup is also available in Milan, Italy – postcode 20154.

For additional photographs, test information or technical questions, please contact us directly through Reverb messaging.