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SYLVANIA

6SL7GT (VT-229) SYLVANIA NOS Black Round Plates Foil Getter AMPLITREX Matched Pair Made in USA '50s.

6SL7GT (VT-229) SYLVANIA NOS Black Round Plates Foil Getter AMPLITREX Matched Pair Made in USA '50s.

$142.00 USD
$142.00 USD
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6SL7GT (VT-229) SYLVANIA NOS Black Round Plates Foil Getter AMPLITREX Matched Pair Made in USA '50s

General Description

This pair of 6SL7GT (VT-229) SYLVANIA NOS tubes, manufactured in the United States in the 1950s, represents an offering of great historical and sonic appeal, perfectly in line with the best American production of the era.

The tubes are distinguished by a particularly refined construction:

  • Black Round Plates
  • Foil Getter
  • Manufactured by SYLVANIA USA – 1950s

An iconic configuration that combines collector's value and musical performance, increasingly difficult to find in NOS condition.

This is a selected and offered matched pair, the result of careful selection aimed at overall consistency and sound performance.

Tested with Amplitrex AT-1000, they achieved an internal VTT Classification: VERY STRONG

The tubes offer stable electrical behavior and consistent balance between sections, making them perfectly usable in hi-fi and musical applications.

Sonic Characteristics

Bass

Full and well-articulated, with a natural presence that gives solidity to the soundstage.

Mids

Rich, textural, and engaging. Vocals emerge with great naturalness, delivering an authentically vintage timbre.

Highs

Sweet and well-extended, with a fluid and never aggressive rendition.

Dynamics

Natural and progressive, with a musical response that enhances every nuance.

Soundstage

Wide and three-dimensional, with good depth and credible instrument separation.

🎧 Use in Hi-Fi Stereo Amplifiers

Ideal for:

  • tube preamplifiers
  • input stages
  • systems oriented towards musicality and timbral realism

This pair offers a warm, balanced, and engaging sound, perfect for enhancing quality listening.

🎸 Use in Musical Amplifiers

Excellent choice for:

  • instrument amplifiers
  • vintage preamplifiers

They offer:

  • great expressiveness in the mids
  • natural dynamic response
  • authentic 1950s sound character

🎯 Note for audiophiles and technicians

  • SYLVANIA USA – 1950s
  • Black Round Plates – Foil Getter
  • Selected pair offered as a matched pair
  • VTT Classification: VERY STRONG

A pair that combines prestige, vintage construction, and rich, musical sound, ideal for those who desire an authentic, selected American 6SL7 with a strong sonic identity.

Test Results:

Tubes tested on Amplitrex AT-1000 Tube tester:

  • Test Conditions: Va = 250V, Vg = -2V
  • Average 100%: Gm = 1600 ; Ia = 2.3 mA
  • Test Result: VERY STRONG

Tube 1:

  • Section 1: Gm = 1500 ; Ia = 2.5 mA
  • Section 2: Gm = 1500 ; Ia = 2.5 mA

Tube 2:

  • Section 1: Gm = 1400 ; Ia = 2.2 mA
  • Section 2: Gm = 1600 ; Ia = 2.6 mA
Additional Tests Performed:
  • Microphonics: Low. Tested and suitable for hi-fi use, including phono stages and guitar amplifiers. Also suitable for V1.
  • Balance: The sections exhibit consistent balance, fully compatible with use in hi-fi and musical amplifiers, in all applications where absolute symmetry between sections is not required.
  • Emission Quality: Excellent – Very strong and stable emission, without fluctuations.
  • Shorts and GAS: Absent.

Condition:

  • Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.
  • Functionality: Perfectly operational.
  • Cosmetic condition: Excellent – Markings excellently preserved, minimal signs of age. See photos for details.
  • Manufacturing Code: absent, identifiable by construction characteristics. 1950s → Sylvania Electric Products Inc., Emporium, Pa.

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.