5AR4 ( GZ34 ) – Amperex Philips Sittard f31 X9A – DD Getter – Holland '50s – 100% Strong Tested – Rectifier Tube

5AR4 ( GZ34 ) NOS NIB AMPEREX by Philips Sittard f31 X9A DD Getter, Tested Tube Rectifier MADE IN HOLLAND '50s

Description:

The 5AR4 / GZ34 AMPEREX , made by Philips Sittard (Holland) in the 1950s, with code f31 X9A and double D-getter , is one of the rarest and most sought-after versions of this rectifier. Appreciated by enthusiasts for its solid construction , extraordinary electrical stability and natural and musical sound contribution , it represents today one of the finest choices for powering high-end hi-fi and instrumental tube systems. This tube is NOS , electrically tested , and comes from a selection of authentic Made in Holland examples.

Bass : compact and well articulated, with a solid and deep structure that supports the system without swelling. The low range is taut, precise, and always under control, with an excellent ability to support high dynamic loads without loss of definition.

Mids : transparent and linear, with a neutral and coherent timbre rendering. Voices and acoustic instruments are reproduced realistically, without emphasis, with a balance that enhances the naturalness of the sound message.

Highs : Airy, refined and always musical. The high-end extension develops with delicacy and precision, helping to maintain a bright but never fatiguing soundstage, even in highly resolving amplifiers.

Dynamics : smooth and responsive, with a prompt response to current demands and a remarkable ability to handle the fastest transients without stiffening. Voltage delivery is progressive, well damped, with a beneficial effect on the overall coherence of the system.

Soundstage : tidy, stable and coherent. Even though it is a rectifier tube, the influence on the sound is clearly perceived in the cleanliness of the black background , in the definition of the microdynamics and in the overall clarity of the musical scene.

The 5AR4 AMPEREX Sittard f31 Double D-Getter is ideal for integrated amplifiers, tube preamplifiers, single-ended or push-pull power amplifiers that use this type of rectifier. It is particularly suitable for systems that require maximum reliability , voltage stability over time and absence of coloration , such as in boutique guitar amplifiers (e.g. Vox AC30 , Matchless DC-30 ) where the quality of the power supply section is crucial to the sonic response of the entire circuit.

🎯 Note for audiophiles :
Very rare version with double D getter , sought after by collectors and enthusiasts for its combination of top-level electrical and musical performance. Ideal for those who want the best in terms of clarity, articulation and neutrality , without introducing any unwanted coloration. A fundamental component for reference hi-fi systems or for vintage amplifiers restored with original components.

🎸 Use in Guitar and Bass Amplifiers

The 5AR4 AMPEREX Sittard with Double D-Getter , thanks to its smooth and stable tension delivery , is one of the most sought-after rectifiers also in the instrumental field. Its progressive, never aggressive response favors a natural compression , much appreciated by musicians who want a warm, round and dynamic sound.

It is particularly suited to circuits that benefit from well-damped tube rectification, such as those found in the Vox AC30 , Marshall JTM45 , Hiwatt DR Series , Matchless DC-30 , or in boutique amps built with NOS parts. In these contexts, the Sittard AMPEREX offers a controlled attack , musical sustain , and a smooth transition to breakup , contributing to a natural, consistent, and always musical touch response.

Test Results:

Tubes tested on FUNKE W19 Tube tester:

• Test Conditions: Va = 60V, Vf = 5V
• Good from: Ia = 55 mA
  
• Average 100%: Ia = 100 mA
  
• Test Result: VERY STRONG

Plate current:

• Section 1: Ia = 100 mA
  
• Section 2: Ia = 102 mA

Additional Tests

• Microphony: 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 (see photo for box condition).
  
• Functionality: Fully functional.
  
• Aesthetic conditions: Sufficient – Writings almost completely disappeared. See photos for details.
  
• Manufacturing Code: f31 X9A - Manufactured in the Sittard plant - in January 1959

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