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SYLVANIA

JHS 6X4W EZ90 NOS NIB SYLVANIA Tested Tube Black Plates Square Getter Made in USA '57

JHS 6X4W EZ90 NOS NIB SYLVANIA Tested Tube Black Plates Square Getter Made in USA '57

€32,50 EUR
€32,50 EUR
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JHS 6X4W EZ90 NOS NIB SYLVANIA Tested Tube Black Plates Square Getter Made in USA '57

Description:

The Sylvania JHS 6X4W (EZ90), manufactured in the USA in 1957 and supplied in NOS NIB (New Old Stock – New in Box) condition, represent one of the most prestigious military versions of this double half-wave rectifier.
The acronym JHS (Joint Army-Navy/Signal Corps) identifies American military production, selected to withstand critical applications where maximum reliability and long life were required.

Unlike the common 6X4, the “W” acronym indicates the ruggedized version, that is, reinforced to resist shocks, vibrations and severe operating conditions.
As reported in the datasheet, the 6X4W was designed to operate in half-wave or full-wave rectification, even in combination with vibratory inverters, and was specifically tested for industrial and military applications subjected to intense mechanical shock and vibration.

This valve, equipped with black plates and square getter , combines construction robustness, operational silence and a unique historical charm, making it ideal for high-quality hi-fi and philological restorations of vintage military or civilian equipment.

Timbral characteristics and sound behavior

  • Bass : Compact and tight, with firm control that adds precision to the low register.
  • Mids : Clear and linear, with a natural sound free of artificial coloration. Voices and acoustic instruments emerge with great realism.
  • Highs : defined and fluid, never harsh, with an elegant detail that gives brilliance without tiring.
  • Dynamics : prompt and consistent, capable of ensuring stable power even in complex passages.
  • Soundstage : Stable and well-focused soundstage, with noise reduction and deeper black background.

🎧 Use in Hi-Fi amplifiers
Perfect for hi-fi equipment and tube tuners using EZ90/6X4 rectifiers, these Sylvania JHS ensure clean power, reliability and long operating life.

🎸 Use in musical instrument amplifiers
In vintage musical instrument amplifiers, they guarantee a warm and quiet sound, with stable harmonic response and free from unwanted noise.

🎯 Note for audiophiles and technicians
The JHS 6X4W (EZ90) Sylvania – Black Plates – Square Getter – NOS NIB – Made in USA '57 represents one of the rarest and most prestigious versions of this rectifier.
Thanks to the reinforced “W” construction, it is particularly suitable not only for philological restorations, but also for those seeking maximum operational reliability in hi-fi systems and musical instruments.
An ideal choice for collectors, restorers and enthusiasts who wish to combine impeccable functionality, historical value and construction authenticity typical of 1950s American military production.

Test Results:

Tubes tested on Funke W19 Tube tester:
Voltage Test: Va = 60V, Vf = 6.3V
Average 100% Ia = 42 mA
Test Result: VERY STRONG

Plate current

Valve:

  • Section 1: Ia = 48 mA
  • Section 2: Ia = 47 mA

Plate current:

Additional Tests

  • 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:

  • Conditions: NOS - NIB - New Old Stock, New In Box - Tested and working - Supplied in original box.
  • Functionality: Fully functional.
  • Cosmetic condition: Good – Lettering partially eroded, but still legible. Valve body in good condition. See photos for details.
  • Manufacturing Code: 702 - Manufactured in the 2nd week of 1957

Find out why our valves 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.

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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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    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.