Sylvania 2A3 Vacuum Tubes – Tested 94.3% Matched Vintage USA Hi-Fi Pair

Sylvania 2A3 Dual-PlateVintage DHT Matched Pair – Professionally Tested

50 mA / 53 mA – 94.3% Ia Matching – Chinaglia CD/P6 90–95% / 85–90%

For sale is a carefully selected pair of vintage Sylvania 2A3 dual-plate directly heated power triodes, manufactured in the United States and professionally tested using both a Metrix U61B and an Elettrocostruzioni Chinaglia CD/P6.

The two tubes show visibly different internal construction, exactly as documented in the photographs. Despite this construction difference, their measured electrical performance is very close, with plate currents of 50 mA and 53 mA at the same Metrix operating point, corresponding to an excellent 94.3% Ia matching.

Individual Test ResultsB2A3001

• Plate current Ia: 50 mA
• Chinaglia CD/P6 efficiency: 90–95%
• Calculated plate dissipation: 12.50 W

B2A3002

• Plate current Ia: 53 mA
• Chinaglia CD/P6 efficiency: 85–90%
• Calculated plate dissipation: 13.25 W

Ia Matching: 94.3%

Difference between tubes: only 3 mA

Sylvania 2A3

The 2A3 is one of the classic directly heated power triodes in high-quality vacuum-tube amplification and remains highly regarded for both single-ended and push-pull amplifier designs.

These vintage Sylvania examples feature:

• original SYLVANIA markings on the glass
• classic dual-plate construction
• black UX4 four-pin bases
• original period labels
• genuine vintage American manufacture
• individual identification and documented professional testing

Important Note About Internal Construction

The two tubes have a visibly different internal structure.

This difference is clearly shown in the listing photographs and is intentionally disclosed.

Despite the construction variation, the electrical measurements demonstrate very close behaviour at the same operating point:

50 mA / 53 mA

This corresponds to a 94.3% minimum-to-maximum Ia matching value.

The pair has therefore been selected on the basis of its measured electrical performance rather than visual construction alone.

Professional Metrix U61B Test

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

Test conditions:

• Heater voltage: 2.5 V
• Plate voltage: 250 V
• Grid voltage: -45 V
• Plate-current range: 100 mA

Measured results:

• B2A3001: 50 mA
• B2A3002: 53 mA

The calculated plate dissipation at this test point is:

• B2A3001: 12.50 W
• B2A3002: 13.25 W

94.3% Ia Matching

The two measured plate currents are:

50 mA / 53 mA

Matching calculation:

50 / 53 × 100 = 94.3%

The difference between the two tubes is only 3 mA, demonstrating close electrical behaviour under identical test conditions.

For transparency, all individual measurements are provided so that the buyer can evaluate the pair according to the requirements of the intended amplifier and bias configuration.

Chinaglia CD/P6 Test

The tubes were independently checked using an Elettrocostruzioni Chinaglia CD/P6 tester.

Results:

• B2A3001: 90–95%
• B2A3002: 85–90%

Both tubes reach the instrument's “EFFICIENTE” operating zone and are fully functional.

The combination of the Chinaglia efficiency test and the closely corresponding Metrix plate-current measurements provides a detailed picture of the electrical condition of both tubes.

Technical Specifications

• Brand: Sylvania
• Model: 2A3
• Quantity: 2 tubes
• Configuration: Selected matched pair
• Type: Directly heated power triode
• Construction: Dual plate
• Base: UX4, 4-pin
• Heater: 2.5 V
• Country of manufacture: United States
• Condition: Vintage, never used, carefully preserved and tested
• Measured Ia: 50 mA / 53 mA
• Ia Matching: 94.3%
• Chinaglia CD/P6: 90–95% / 85–90%
• Identification codes: B2A3001 / B2A3002
• Test equipment: Metrix U61B + Elettrocostruzioni Chinaglia CD/P6
• Test date: July 23, 2026
• Original boxes: Not included

The photographs show the exact two tubes offered for sale and document their internal construction, original Sylvania markings, period labels, glass envelopes, bases, pins and professional 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.

Each tube will be individually protected with shock-absorbing material and placed inside a rigid outer shipping box.

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.