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SYLVANIA

6SN7GTB NOS SYLVANIA CHROME TOP Matched Quad Yellow Dot Black Plates Tubes USA 1955

6SN7GTB NOS SYLVANIA CHROME TOP Matched Quad Yellow Dot Black Plates Tubes USA 1955

Regular price 746.00 NIS
Regular price Sale price 746.00 NIS
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6SN7GTB NOS SYLVANIA CHROME TOP Matched Quad Yellow Dot Black Plates Tubes - Same Codes - Made in USA '55

The matched quartet of 1955 Sylvania 6SN7 GTBs, with black plates , chrome tops , yellow dot selector, and identical part numbers , represents one of the finest and most consistent NOS configurations in postwar American production. The yellow dot was a factory-applied marking by Sylvania to identify tubes selected for low noise and microphony, intended for critical military, professional, and high-end audio applications. This generation’s build quality, combined with accurate matching, makes them an excellent choice for tube preamplifiers , push-pull amplifier driver stages , or high-end dual mono restorations , where tonal consistency, quiet operation, and natural musicality are essential.

These valves are distinguished by a transparent and three-dimensional voice , with a neutral but musical character, capable of enhancing the microdynamics without forced colorations.

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

Mids : Clear and natural. The midrange is balanced and free of artifacts , with well-centered vocals and a realistic rendition 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 listening sessions without fatigue.

Dynamics : Fluid and modulated. The dynamic response is progressive , capable of naturally reproducing minimal nuances , but also of sustaining energetic passages without stiffening. The valves react quickly but in a controlled manner, ensuring constant musicality.

Soundstage : Wide and stable. The soundstage is wide and deep , with excellent instrument placement and coherent layering . Coherence between channels, ensured by matching and identical codes, contributes to a precise and relaxed stereo image.

🎧 Use in Push-Pull Stereo Hi-Fi Amplifiers
This matched quartet is ideal for driver stages, mid-stages, or preamp power amps in high-quality stereo setups. It offers channel-to-channel uniformity, low noise, and refined tonal response , making it perfect for transparent, high-end systems, both modern and vintage.

🎸 Use in Instrument Amplifiers
While not the primary choice for guitar amps, the Sylvania Chrome Top 6SN7 GTB finds its place in boutique designs , jazz guitar amps, or in studio-grade circuits, where controlled harmonic output and transparency are preferred over driven distortion.

🎯 Note for audiophiles and technicians
A rare and valuable NOS selection, with perfectly matched, quiet and stable tubes , perfect for dual mono restorations, balanced stages and applications where precision and musicality must coexist. The combination of black plates, chrome top and yellow selection dot is considered among the most successful of the 1950s Sylvania school.

Test Results:

Valves tested on Amplitrex AT-1000 Tube tester :

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

Valve 1:

  • Section 1: Gm = 2400 ; Ia = 6.4 mA
  • Section 2: Gm = 2500 ; Ia = 7.4 mA

Valve 2:

  • Section 1: Gm = 2500 ; Ia = 7.2 mA
  • Section 2: Gm = 2400 ; Ia = 6.6 mA

Valve 3:

  • Section 1: Gm = 2500 ; Ia = 6.8 mA
  • Section 2: Gm = 2400 ; Ia = 6.6 mA

Valve 4:

  • Section 1: Gm = 2400 ; Ia = 6.6 mA
  • Section 2: Gm = 2500 ; Ia = 7.0 mA
Additional Tests Performed:
  • Microphonics: Standard. Tested and approved for use in hi-fi and guitar amplifiers.
  • Output Quality: Excellent – Very strong and stable output, no fluctuations.
  • Short circuits and GAS: Absent.

Conditions:

  • Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.
  • Functionality: Fully functional.
  • Cosmetic condition: Excellent – Excellently preserved lettering, minimal signs of wear. See photos for details.
  • Manufacturing Code: 411 526 Manufactured by SYLVANIA USA 411 → EIA code of the client ( Hardwick, Hindle, Inc., Newark 5, N. J) - 526 → 26th week of 1955

Find out why our valves are different →

 

Condizioni di vendita e sicurezza

Anti-Tamper Security Seal Policy:
Each product is sealed to guarantee quality and integrity.
The right of withdrawal is subject to the seal remaining intact, as provided for by the Consumer Code.

Eco-Friendly Packaging:
The tube will be shipped with protective packaging to ensure safety during transport.
We use recycled and recyclable paper for packaging, along with brown ECO-KRAFT adhesive tape, eco-friendly and solvent-free.

Important Notes:
This tube, manufactured according to the standards of its era, is designed to operate in equipment compatible with vintage tubes.
It is recommended to follow standard safety guidelines to avoid malfunctions or damage.

Safety Assurance:
Although not tested according to modern GPSR regulations, this tube was designed to operate safely under the conditions for which it was manufactured.
We recommend using it only with equipment that supports vintage tubes, in order to avoid risks of malfunction or damage.
Technical data note:
In some cases, the technical data provided may be based on datasheets from other manufacturers or on equivalent historical specifications, when a specific official datasheet for the production batch of the listed item is not available.
Electrical characteristics may vary slightly depending on the production batch and manufacturing period, as is typical for thermionic components.

Safety Information:
Warning: Keep out of reach of children.
To be used under adult supervision.
Use the product only with equipment designed for vintage tubes.

Shipping & Returns

Shipping & Returns

Shipping Costs

Shipping costs vary depending on the total amount of the items in the cart and are calculated automatically during the checkout process.
All shipments are fully insured. The courier is automatically selected based on destination, weight, and shipment characteristics.

Shipping Times and Delivery

The indicated delivery times are purely indicative.
Any delays, storage issues, or operational changes made by the carrier (for example during peak periods such as holidays) are not attributable to Vacuum Tubes Treasures.

In such cases, we will nevertheless provide the Customer with all necessary support to open claims or assistance requests with the appointed courier.

International Shipping (Non-EU Countries)

For orders shipped to countries outside the European Union, any customs duties, import taxes, or additional charges are the sole responsibility of the recipient.
Vacuum Tubes Treasures has no control over these costs, which may vary from country to country. Customers are therefore advised to contact their local customs authorities prior to placing an order.

Warranty

All products sold by Vacuum Tubes Treasures are covered by the legal warranty of conformity, in accordance with Italian Legislative Decree No. 206/2005 (Consumer Code) and the Italian Civil Code (Articles 1490 et seq.), under the conditions set out below.

Warranty for Vacuum Tubes

Vacuum tubes, being components subject to wear and of vintage or specialized nature, are covered by a specific warranty of 6 (six) months from the date of delivery.
The warranty covers exclusively proven manufacturing or conformity defects that arise during proper use in accordance with technical specifications.

The warranty does not cover:

  • normal wear and tear,
  • subjective sound preferences,
  • use in incompatible equipment,
  • tampering or improper use.

Right of Withdrawal

Purchases made on the Vacuum Tubes Treasures website are governed by Italian regulations on distance contracts (Legislative Decree No. 206/2005).

Consumers have the right to withdraw from the contract within 14 (fourteen) days from the date of receipt of the goods, without providing any reason.

Conditions for Exercising the Right of Withdrawal

The right of withdrawal may be exercised only if:

  • the product has not been used,
  • the product is returned in its original condition,
  • the tamper-evident security seal is intact and not broken.

📌 Returns are not accepted for reasons related to sound preference, tube rolling, or subjective audio evaluation.
As with a music recording, a vacuum tube cannot be returned simply because its sound does not match personal taste.

Effects of Withdrawal

In the event of a valid withdrawal:

  • all payments received, including standard shipping costs, will be refunded,
  • refunds will be issued within 14 days from receipt of the returned goods,
  • the refund may be withheld until the goods have been received and inspected.

Refunds will be made using the same payment method used for the original transaction, unless otherwise agreed.

Return Shipping Costs

Return shipping costs are borne by the Customer, except in cases of:

  • verified defective products,
  • errors attributable to Vacuum Tubes Treasures.

In such cases, return shipping costs will be fully covered by us.

Damaged or Incorrect Items

If the Customer receives a damaged or incorrect item, it must be reported within 5 (five) working days from delivery, by email or telephone, clearly stating the issue.

Uncollected Parcels, Storage, and International Shipments

It is the Customer’s responsibility to monitor the shipment and promptly arrange for collection or customs clearance.
Any costs, delays, or losses resulting from:

  • failure to collect the parcel,
  • prolonged storage,
  • abandonment of the parcel at customs,

do not entitle the Customer to any refund.

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.