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RCA

12AX7 / ECC83 RCA Matched Pair Long Black Plates Square Tilt getter Made in USA '58

12AX7 / ECC83 RCA Matched Pair Long Black Plates Square Tilt getter Made in USA '58

$335.00 AUD
$335.00 AUD
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12AX7 / ECC83 RCA Matched Pair – Long Black Plates – Square Tilt Getter – Made in USA 1958

AMPLITREX Tested – Low Noise & Microphonics – Vintage American Black Plates

Description

Matched pair of 12AX7 / ECC83 RCA, produced Made in USA 1958, selected for compatible hi-fi and musical applications where vintage American sound character, low noise, and operational consistency between the two tubes are required.

The construction with Long Black Plates and rare Square Tilt Getter identifies one of RCA's most fascinating configurations from the late 1950s, highly appreciated for its musicality, harmonic richness, and strong sonic personality.

The tubes are used, carefully tested in our lab using an Amplitrex AT-1000 Tube Tester, classified as Low Noise & Microphonics, and selected as a Matched Pair for good operational consistency and uniform sound reproduction.

From an aesthetic point of view, the pair is in particularly beautiful and very clean condition for its age: the RCA silk screen is still well preserved, the internal structures are visually fascinating, and the overall set retains all the charm of authentic 1950s American black plates. See photos for details.

Sonically, it offers a broad, rich, and musical reproduction, with full and natural bass, textured and harmonically dense mids, and fluid, never aggressive highs. The overall character is warm, engaging, and refined, typical of the best vintage RCA long black plates.

Suitable for hi-fi preamplifiers, line stages, compatible phono stages, integrated amplifiers, driver stages, vintage amplifiers, boutique amplifiers, and circuits compatible with 12AX7 / ECC83.

An RCA 12AX7 / ECC83 Long Black Plates pair from 1958, genuinely tested and selected by Vacuum Tubes Treasures, ideal for those seeking authentic, silent vintage American tubes with a rich, natural, and deeply musical sound character.

Test Results

Tested on AMPLITREX AT-1000 Tube Tester

Voltage Test: Va = 250V, Vg = -2V
Average 100%: Gm = 1600 ; Ia = 1.2 mA
TEST RESULT: VERY STRONG

Tube #8:

  • Section 1: Gm = 1400 ; Ia = 0.8 mA
  • Section 2: Gm = 1400 ; Ia = 0.8 mA

Tube #10: 

  • Section 1: Gm = 1500 ; Ia = 0.8 mA
  • Section 2: Gm = 1400 ; Ia = 0.8 mA

Additional Tests performed:
  • Microphonics: Low Noise & Microphonics – Tested and compliant for use in hi-fi systems and guitar amplifiers.
  • Noise: Low and well controlled. Quiet operation in hi-fi and musical amplifiers in designated positions.
  • Emission Quality: Strong – Strong and regular emission, suitable for any application.
  • Shorts and GAS: Absent.

Condition:

  • Condition: Vintage Tubes - Tested and fully functional. Supplied in our custom box for optimal protection. 
  • Functionality: Perfectly operational.
  • Aesthetic condition: Excellent – Markings excellently preserved, minimal signs of age. See photos for details.

Manufacturing Code:

  • 58-09 → RMA/EIA Open Date Code → manufactured the 9th week of 1958 → Radio Corporation of America, Camden, N. J.

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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.

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.