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SYLVANIA

6SN7GTA NOS SYLVANIA Chrome Top Matched Pair - Same Production Code - Low Noise & Microphonics - AMPLITREX Tested

6SN7GTA NOS SYLVANIA Chrome Top Matched Pair - Same Production Code - Low Noise & Microphonics - AMPLITREX Tested

$291.00 AUD
$291.00 AUD
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6SN7GTA NOS SYLVANIA – Short Base Chrome Top – Matched Pair – Same Data Codes – Made in USA 1955

AMPLITREX Tested – VERY STRONG – Green Dot & Gray Dot – Low Noise & Microphonics

Test Results:

Tubes tested on an Amplitrex AT-1000 Tube Tester:

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

Tube #36

  • Section 1: Gm = 2700 ; Ia = 7.6 mA
  • Section 2: Gm = 2600 ; Ia = 7.0 mA

Tube #9

  • Section 1: Gm = 2600 ; Ia = 7.6 mA
  • Section 2: Gm = 2700 ; Ia = 8.2 mA

Additional Tests:

  • Burn-in / Stability Test: 48h – OK
  • Microphonics and noise: Very Low. Tested and suitable for use in hi-fi equipment and guitar amplifiers, including the most sensitive audio stages.
  • Balance: Very good. The sections are consistent and well-aligned, making the tube suitable for use as a phase inverter in hi-fi and instrument applications.
  • Emission: Excellent – Very strong and stable emission, without fluctuations.
  • Short Circuits / Gas: absent

Description

Exceptional NOS pair of 6SN7GTA Sylvania, manufactured in the United States in 1955 and carefully selected as a Matched Pair. Both specimens share the identical manufacturing code 288 / 513, traceable to the 13th week of 1955, and feature the characteristic Short Base Chrome Top construction, a hallmark of Sylvania's renowned American production in the 1950s.

The measurements performed with the Amplitrex AT-1000 show a transconductance between 2600 and 2700 µmhos, with an average of 2650 µmhos for each tube, exceeding the nominal reference of 2600. The anode currents range from 7.0 to 8.2 mA, with averages of 7.3 and 7.9 mA respectively, compared to the 9.0 mA reference. Results that confirm a very strong transconductance and a particularly uniform match, with well-balanced sections and minimal differences between the two specimens.

The selection includes 48 hours of burn-in, during which the stability of performance was verified, accompanied by tests that confirmed strong and constant emission, without short circuits or gas. Particular attention was paid to noise and microphonics, with very low results. The special Green Dot and Gray Dot selection adds value to this pair, especially for use in the most sensitive audio stages.

The 6SN7GTA Sylvania tubes find application in hi-fi preamplifiers, driver stages, headphone amplifiers, and compatible phase inverter circuits. Sylvania production from this period is particularly appreciated by vintage tube enthusiasts for a musical presentation generally described as open, balanced, and rich in detail, with an expressive naturalness that fuels interest in them within the world of tube audio.

Belonging to the same production week in March 1955, the excellently preserved original markings and excellent cosmetic condition make this pair particularly interesting from a historical perspective as well. An opportunity for those seeking authentic 1950s NOS Sylvania tubes, with documented electrical characteristics, careful matching, and a selection designed to enhance their qualities in the most demanding audio applications.

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.
  • Special selection: Green Dot and Gray Dot, with low noise and microphonics verified using the Amplitrex AT-1000.
  • Manufacturing code: Sylvania Electric Products Inc., USA – original marking on the base 288 / 513. 288 Sylvania Internal code. 513 - 13th week of 1955 (March 1955).

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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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