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SYLVANIA

6SN7 GTA NOS Sylvania – Black Plates Tall Glass Matched Quad Tubes USA '56

6SN7 GTA NOS Sylvania – Black Plates Tall Glass Matched Quad Tubes USA '56

₩568,000 KRW
₩568,000 KRW
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6SN7 GTA NOS SYLVANIA Black Plates TALL GLASS Matched Quad & Codes Made in USA '56

Matched Quad – AMPLITREX Tested – Low Noise & Microphonics – Vintage American Sylvania Production

Test Results:

Tubes tested on Amplitrex AT-1000 Tube tester:

  • Test Conditions: Va = 250V, Vg = -8V
  • Average 100% Gm = 2600 ; Ia = 9.0 mA
  • Test Result: VERY STRONG

Tube 1:

  • Section 1: Gm = 2500 ; Ia = 7.8 mA
  • Section 2: Gm = 2600 ; Ia = 8.0 mA

Tube 2:

  • Section 1: Gm = 2500 ; Ia = 6.6 mA
  • Section 2: Gm = 2600 ; Ia = 7.4 mA

Tube 3:

  • Section 1: Gm = 2500 ; Ia = 6.8 mA
  • Section 2: Gm = 2600 ; Ia = 7.0 mA

Tube 4:

  • Section 1: Gm = 2500 ; Ia = 6.6 mA
  • Section 2: Gm = 2600 ; Ia = 7.2 mA

Additional Tests Performed

  • Burn-in / Stability Test: 48h – OK
  • Microphonics: Low. Tested and suitable for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages.
  • 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

Precious matched quad of 6SN7GTA NOS Sylvania, produced in the United States in 1956 and characterized by the sought-after Black Plates with Tall Glass construction, one of the most appreciated configurations of American Sylvania production from the mid-1950s.

The four tubes belong to the same production period and have consistent codes, a particularly interesting element in a Matched Quad intended for hi-fi and professional applications where uniformity, stability, and channel consistency are important requirements. Sylvania's construction of the time is known for its robustness, long operating life, and a full, natural sound character.

The quad has undergone 48 hours of burn-in / stability testing and was then carefully tested and selected in our laboratory using an Amplitrex AT-1000 Tube Tester, achieving a VERY STRONG classification. All tubes were found to be Low Noise & Microphonics, with excellent transconductance consistency and well-aligned internal sections, characteristics that make the quad particularly interesting for stereo configurations and high-level audio applications.

Sonically, Sylvania Black Plate tubes from this period are appreciated for an authoritative, rich, and natural reproduction, with full and well-controlled bass, a rich and musical mid-range, open but never aggressive high frequencies, and a wide, stable, and three-dimensional soundstage. The overall character is dynamic, fluid, and engaging, with that combination of body, balance, and musicality typical of the best Sylvania productions of the 1950s.

Ideal for hi-fi preamplifiers, driver stages, phase inverters, headphone amplifiers, vintage restorations, and all equipment compatible with 6SN7GTA / 6SN7GT that requires a high-quality matched quad. The Low Noise & Microphonics selection also makes them particularly suitable for the most sensitive audio applications.

The tubes are NOS – New Old Stock, carefully tested and perfectly functional. The aesthetic condition is excellent, with well-preserved silk-screening and minimal signs of age.

A rare matched quad of authentic Sylvania 6SN7GTA Black Plates Tall Glass from 1956, genuinely tested, selected, and matched by Vacuum Tubes Treasures, ideal for those seeking one of the most appreciated American productions of the 6SN7 family in a hard-to-find matched quad configuration.

Condition:

  • Condition: NOS - New Old Stock - Tested and functional - Supplied in our custom box for optimal protection.
  • Functionality: Perfectly operational.
  • Aesthetic Condition: Excellent – Markings excellently preserved, minimal signs of age. See photos for details.
  • Manufacturing Code: 722 622 → manufacturer Sylvania Electric Products Inc., Emporium, Pa. - 722 indicates the customer, i.e., Milwaukee Resistor Co., Milwaukee 4, Wis. - 622 → 6 ( out of three digits ) → Produced in the 22nd week of 1956

Discover why our tubes are different →

Terms of Sale & Safety

Sales Terms & Product Safety

Each vacuum tube is carefully selected, tested, and verified in our laboratory before shipment. Where stated in the listing, test results, matching data, and declared characteristics refer to measurements performed using the specified test equipment and operating conditions.

Sound descriptions are provided for guidance only and reflect the characteristics generally associated with that particular tube type. Personal sound preferences, tube rolling, or perceived differences between audio systems do not constitute a product defect.

Before installation, please verify the tube’s electrical and mechanical compatibility with your equipment and follow the manufacturer’s instructions.

New production and NOS tubes are shipped with a tamper-evident security seal and internal technical documentation to ensure traceability of the product’s condition at the time of shipment.

Product Safety (GPSR)

Vacuum tubes are electronic components intended exclusively for use in compatible equipment and must be installed in accordance with the equipment manufacturer’s instructions.

Due to their historical or vintage nature, certain technical specifications may be based on original datasheets or equivalent technical documentation when documentation from the specific manufacturer is unavailable.

Use only with suitable equipment. Keep out of reach of children.

Shipping & Returns

Shipping & Returns

We ship worldwide using carefully selected express carriers and protective packaging specifically designed for vacuum tubes.

If you change your mind, you may exercise your right of withdrawal within 14 days of delivery, where applicable under the relevant consumer protection laws. The product must be returned complete with its original packaging and accessories, in the same commercial condition in which it was received. Return shipping costs are the responsibility of the customer.

Every returned item undergoes a technical inspection. Installation, use, tube rolling, or any other handling may reduce the product’s commercial value and may affect the refund amount, in accordance with applicable law.

If you believe the product has a lack of conformity, our laboratory will carry out the necessary inspections and apply the remedies provided by the applicable consumer protection legislation.

For further details, Customers are invited to consult the “Terms and Conditions” and “Refund Policy” sections of our website, or to contact us before placing an order.

Vacuum Tubes Treasures
www.vtt.store | www.vacuumtubestreasures.com
📧 info@vacuumtubestreasures.com

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  • ATTENTION PLEASE

    Please understand that the writing on the glass of vintage valves has become very delicate over the years and comes off easily. You must handle them with extreme care to avoid this. Wear and damage to the writing on the valves reduces their market value and causes damage. Please exercise extreme caution.

  • ATTENTION PLEASE

    We wish to inform you that any attempts to manipulate shipping destination information in order to obtain lower shipping rates may be considered fraudulent acts. Please provide accurate information and contact us if you have any concerns. We reserve the right to review and, if necessary, cancel orders that we deem to be in violation of our conditions. Thank you for your understanding and cooperation.