12AU7A / ECC82 NOS Baldwin by RAYTHEON Matched Quad Tubes Long Black Plates Halo Getter Made in USA '61

12AU7A / ECC82 NOS BALDWIN by RAYTHEON – Long Black Plates – Halo Getter – Matched Quad – Made in USA – 1961

AMPLITREX Tested – VERY STRONG – Low Noise & Microphonics – Vintage American Raytheon Production

Test Results

Tubes tested on AMPLITREX AT-1000 Tube Tester

Test Conditions: Va = 250V, Vg = -8.5V
Average 100%: Gm = 2200 ; Ia = 10.5 mA
Test Result: VERY STRONG

Additional Tests Performed

• Burn-in / Stability Test: 48h – OK
• Microphonics: Low. Tested and suitable for hi-fi use, including in phono stages and guitar amplifiers. Also suitable for V1 positions.
• Balance: The sections are consistent and well-aligned, making the tubes suitable for use as phase inverters in hi-fi and instrumental applications.
• Emission Quality: Excellent – very strong and stable emission, without fluctuations.
• Shorts and GAS: Absent.

Description:

A prized matched quad of 12AU7A / ECC82 NOS Baldwin tubes produced by Raytheon in the USA, dating back to approximately the early 1960s. The sought-after Long Black Plates construction with Halo Getter identifies one of Raytheon's best productions of the era, which is increasingly difficult to find in authentic NOS condition, especially in a matched quad configuration.

Baldwin-branded tubes were intended for high-quality professional equipment, where reliability, long life, and quiet operation were essential requirements. Behind the Baldwin brand lies the excellent American Raytheon production, highly valued by audiophiles for its construction and sound qualities.

The quad has been carefully tested and selected in our laboratory using an Amplitrex AT-1000 Tube Tester, earning a VERY STRONG rating. All tubes were found to have Low Noise & Microphonics and exhibit excellent electrical balance, a fundamental characteristic for amplifiers and preamplifiers that require a perfectly matched quad to ensure consistent performance and maximum sonic uniformity.

Sonically, Raytheon Long Black Plate tubes are known for authoritative and refined reproduction, with deep and well-controlled bass, a rich and natural mid-range, open yet smooth high frequencies, and a wide, stable, and three-dimensional soundstage. They offer engaging musicality and remarkable transparency while retaining the typical warmth of the best American tubes of the period.

Ideal for push-pull amplifiers, reference preamplifiers, driver stages, phase splitters, headphone amplifiers, and all 12AU7A / ECC82 compatible equipment that requires a high-quality matched quad.

The tubes are NOS (New Old Stock), carefully tested, and fully functional. Aesthetic condition is good, with partially eroded but still legible silkscreening, which has no effect on electrical performance.

A rare matched quad of authentic Raytheon Long Black Plates, genuinely tested and selected by Vacuum Tubes Treasures, ideal for those who desire one of the most highly regarded American 12AU7s ever produced in the most difficult-to-find configuration.

Condition

• Condition: NOS – New Old Stock – tested and functional. Supplied in our custom box for optimal protection.
• Functionality: Perfectly operational.
• Cosmetic Condition: Good – Partially eroded lettering, but still legible. Tube body in good condition. See photos for details.
• Manufacturing Code: P28061-17C → 280 → Raytheon Manufacturing Company, Waltham 54, Mass. ; 61-17 → RMA/EIA Open Date Code → manufactured in the 17th week of 1961

Discover why our tubes are different →