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SYLVANIA

6SN7 GTB NOS NIB SYLVANIA CHROME TOP Export Quality AMPLITREX Tested Tube Black Plates USA '50s

6SN7 GTB NOS NIB SYLVANIA CHROME TOP Export Quality AMPLITREX Tested Tube Black Plates USA '50s

HK$830.00 HKD
HK$830.00 HKD
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6SN7GTB NOS NIB SYLVANIA CHROME TOP Export Quality AMPLITREX Tested Tube Black Plates USA '50s

The 6SN7 GTB Sylvania Export Quality, with black plates and a chrome top, represents one of the most refined and consistent NOS configurations of post-war American production. The green dot was a factory marking applied by Sylvania to identify tubes selected for low noise and microphonics, intended for critical applications in military, professional, and high-end audio fields. The construction quality of this generation makes it an excellent choice where tonal uniformity, quietness, and natural musicality are essential requirements.

These tubes are distinguished by a transparent and three-dimensional sound, with a neutral yet musical character, capable of enhancing microdynamics without forced coloration.

Bass: tight and well-defined. The low end is articulate, dry, and free from bloat, offering a controlled and stable harmonic foundation. Perfect for maintaining clarity and precision in the lower registers, even with complex passages.

Mids: clear and natural. The mid-range is balanced and free from artifacts, with well-centered vocals and a realistic reproduction of acoustic instruments. There is no artificial emphasis, but a consistent transparency that facilitates deep and engaging listening.

Highs: fine and non-fatiguing. The high range is delicate, extended, and airy, with a discreet brilliance and detail well integrated into the musical fabric. Excellent for long, fatigue-free listening sessions.

Dynamics: fluid and modulated. The dynamic response is progressive, capable of reproducing minimal nuances with naturalness, while also sustaining energetic passages without stiffening. The tubes react quickly but controllably, ensuring constant musicality.

Soundstage: wide and stable. The soundstage is wide and deep, with excellent instrument placement and consistent layering. The precision of the stereo image benefits from the electrical stability and constructive consistency typical of this Sylvania production.

🎧 Use in Stereo Hi-Fi Amplifiers
An ideal choice for high-level preamplifiers and driver stages. The 6SN7 Sylvania Chrome Top is renowned for its ability to combine transparency and warmth, offering a perfect balance between detail and musicality, with extended listening sessions always enjoyable.

🎸 Use in Instrument Amplifiers
Also highly appreciated in boutique and vintage guitar amplifiers, where it delivers a round, harmonic, and natural sound. Its soft yet detailed reproduction makes it ideal for blues, jazz, and classic rock.

🎯 Note for audiophiles and technicians
The 6SN7 GTB Sylvania Chrome Top Green Dot Black Plates is one of the most sought-after variants of this iconic tube.
It combines the military/industrial construction solidity of the era with the tonal refinement that made Sylvania a legendary name among audiophiles and collectors.
A rare opportunity to own not just a tested NOS tube, but a true fragment of authentic American sound.

Test Results:

Tubes tested on Amplitrex AT-1000 Tube tester:

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

Tube :

  • Section 1: Gm = 2900 ; Ia = 9.2 mA
  • Section 2: Gm = 2700 ; Ia = 8.0 mA
Additional Tests Performed:
  • Microphonics: Low Noise & Microphonics – Tested and compliant for use in hi-fi systems and guitar amplifiers.
  • Emission Quality: Excellent – Very strong and stable emission, without fluctuations.
  • Shorts and GAS: Absent.

Condition:

  • Condition: NOS - NIB - New Old Stock, New In Box - Tested and working - Supplied in Original box.
  • Functionality: Perfectly operational.
  • Cosmetic Condition: Excellent – Markings excellently preserved, minimal signs of age. See photos for details.
    Manufacturing Code: undecipherable, identifiable by construction characteristics. 1950s

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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.

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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.

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