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RCA

5751 RCA Triple Mica Black Plates Square Getter Amplitrex Tested Tube USA

5751 RCA Triple Mica Black Plates Square Getter Amplitrex Tested Tube USA

15,300 ISK
15,300 ISK
Sale Sold out
Shipping calculated at checkout.

5751 RCA Triple Mica Black Plates Square Getter Made in USA '50s

Low Noise & Microphonics – VERY STRONG - Balanced Sections - Vintage American RCA Production

Test Results:

Tube tested on AMPLITREX AT-1000 Tube Tester:

  • Test Conditions: Va = 250V ; Vg = -3V
  • 100% Average: Gm = 1200 ; Ia = 1.0 mA
  • Test Result: VERY STRONG

Tube :

  • Section 1: Gm = 1400 ; Ia = 1.7 mA
  • Section 2: Gm = 1400 ; Ia = 1.6 mA
Additional tests performed:
  • Burn-in / Stability Test: 48h – OK
  • Microphonics: Low. Tested and compliant for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages.
  • Balance: Very good. The sections are consistent and well-aligned, making the tube also suitable for use as a phase inverter in hi-fi and instrumental applications.
  • Emission Quality: Excellent – Very strong and stable emission, without fluctuations.
  • Shorts and GAS: None.

Description:

This 5751 RCA Triple Mica Black Plates is a particularly interesting example of American tube production attributable to the 1950s. The internal construction features black plates, a triple mica spacer, and a square getter, a robust and recognizable configuration developed to ensure mechanical stability and operational reliability.

The manufacturing code and external silkscreen prints are no longer visible; the attribution to RCA production and the indicated period is therefore based on the construction characteristics of the specimen. Despite signs of age and the absence of markings, the internal structure is intact, well-preserved, and clearly documented in the photographs.

After a 48-hour burn-in cycle, the tube was tested with an Amplitrex AT-1000, recording Gm 1400 in both sections, with anode currents of 1.7 and 1.6 mA respectively. The transconductance values exceed the nominal reference and confirm very strong, stable emission free of fluctuations.

The excellent balance is one of the main strengths of this specimen. The two sections present the same Gm value and nearly identical anode currents, making the tube also suitable as a phase inverter, as well as a driver or in stages where uniformity and good symmetry are required.

The selection for low noise and microphonics allows it to be used even in the most sensitive audio stages of hi-fi equipment and guitar amplifiers. From a sonic perspective, this RCA production is appreciated for a full-bodied, musical, and natural performance, with a rich midrange, present bass, and smooth, well-integrated high frequencies.

A vintage 5751 Made in USA of significant technical and historical interest, capable of combining Triple Mica construction, black plates, and a square getter, with emission above reference and perfectly balanced sections. Although it lacks markings and shows evident signs of age, the tube has been carefully tested, is perfectly operational, and is free of shorts or gas.

Conditions:

  • Condition: Vintage Tubes - Tested and perfectly functional. Supplied in our custom box for optimal protection.
  • Functionality: Perfectly operational.
  • Cosmetic condition: Adequate – Markings absent, general aesthetic shows evident signs of age. See photos for details.
  • Manufacturing Code: Code absent. Production indicatively attributable to the 1950s based on construction characteristics.

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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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