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RCA

5U4GB 5AS4A RCA Black Plates Tube Top Side Square Getter Rectifier Made in USA '64

5U4GB 5AS4A RCA Black Plates Tube Top Side Square Getter Rectifier Made in USA '64

€69,90 EUR
€69,90 EUR
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5U4GB 5AS4A Baldwin by RCA Black Plates Tube Top Side Square Getter Rectifier Made in USA '64

Note: Price refers to one selected valve

Description:

The 5U4GB / 5AS4A Baldwin by RCA , in this 1964 version with black plates , square getter in the top and side position, represents one of the most stable and balanced variants of the classic RCA rectifier, selected for the organ sector but fully compatible with high-end audio use.

Bass : precise and controlled. The bass extension is solid but never intrusive, with a tight and coherent response even under complex loads. The bass structure contributes to rhythmic stability without introducing inaccuracies or bloat.

Mids : Clean and well-articulated. The midrange is presented in a neutral and uncluttered manner, with particular attention to the tonal coherence of vocals and acoustic instruments. There is no tendency to harden or thin out, which favors the overall balance.

Highs : Sober and natural. The high range is well-integrated, without excessive brightness or obvious grain. Detail is present but never invasive, leaving room for musicality and reducing listening fatigue even during prolonged listening.

Dynamics : linear and stable. Transient response is smooth, with predictable and well-balanced behavior even under variable load conditions. No "pumping" effect, just an organic dynamic progression.

Soundstage : Coherent and well-structured. The stereo image is clear and stable, with good definition of the soundstage. The soundstage develops naturally in depth and width, without forced expansion.

🎧 Use in Headphone Amplifiers and Hi-Fi Driver Stages
Perfect for tube DACs and reference preamps, this tube offers clean delivery and extremely low noise. Its tonal balance and transparency are ideal for enhancing microdynamics and depth with demanding headphones like the Focal Utopia , Sennheiser HD800S , and ZMF Atrium .

🎸 Use in Guitar and Bass Amplifiers
Often installed in vintage Fender amplifiers (such as the Twin Reverb, Bandmaster and Showman) and their boutique derivatives, this rectifier provides natural progressive compression , with a controlled musical sag , perfect for cleans, blues and the dynamic crunch typical of the 60s American sound.

🎯 Note for audiophiles and technicians
A technically robust and musically neutral tube, ideal for those looking for a stable, silent and reliable electric base.

Test Results

Tubes Tested on Funke W19 Tube Tester:

Voltage Test: Va = 100V, Vf = 5V
Good from: Ia = 78 mA
Average 100%: Ia = 120 mA
TEST RESULT: VERY STRONG

Valve 1 :   SOLD

  • Section 1 : Ia = 123 mA
  • Section 2 : Ia = 123 mA

Valve 2 :

  • Section 1 : Ia = 124 mA
  • Section 2 : Ia = 120 mA

Additional Tests Performed:
  • Operation: Stable valve, quiet in operation, and suitable for regular and controlled power supply. Tested with a Funke W19 tester.
  • Output Quality: Excellent – Very strong and stable output, no fluctuations.
  • Short circuits and GAS: Absent.

Conditions:

  • Condition: Vintage tubes - Tested and in perfect working order. Shipped in our custom box for optimal protection.
  • Functionality: Fully functional.
  • Aesthetic condition: Very good – Clearly legible writing with minor signs of wear, no obvious defects. See photos for details.
  • Manufacturing Code: 64-25 - Made by RCA USA - 25th week of 1964

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.

Vacuum Tubes Treasures
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📧 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.