12AX7 / ECC83 NOS MULLARD Blackburn 1958 – Long Gray Plates Goalpost Getter – Matched Pair

12AX7 / ECC83 NOS MULLARD – Blackburn (Great Britain) 1958

Long Gray Plates – Goalpost / Dual Post Getter – Matched Pair

Description:

This matched pair of NOS MULLARD 12AX7 / ECC83s , produced in the historic Blackburn factory (Great Britain) in 1958 , represents one of the rarest, earliest and most sought-after versions of the entire Mullard production.

The construction with long gray plates and goalpost / dual post getter identifies a very early technical configuration , today particularly appreciated for its construction quality, mechanical stability and sonic refinement. It is a tube that fully embodies the golden age of Mullard, when the absolute priority was musical performance and reliability over time.

The pair is NOS , selected as a Matched Pair , and features low noise and limited microphonics , making it suitable even for sensitive positions in the circuit.

Sound Characteristics

Bass: Deep, rounded, and perfectly controlled. The low end is authoritative yet elegant, with a solid structure that supports the music without weighing it down.

Mids: The heart of this version. Rich, textured, and three-dimensional, with extremely natural voicings and a deep harmonic texture, typical of first-generation Mullards.

Highs: Silky, refined, and well-extended. The highs are sweet and never aggressive, with a naturalness that favors long, highly engaging listening sessions.

Dynamics: Fluid, expressive, and very natural. Microdynamics are excellent, with a responsive yet composed transient response.

Soundstage: Wide, deep, and beautifully layered. The soundstage is three-dimensional and stable, with realistic instrument placement and excellent separation.

🎧 Use in Hi-Fi Amplifiers

Ideal for:

• high-level input and pre-amplification stages,
• high-end hi-fi preamplifiers and integrated amplifiers,
• systems that seek tonal refinement, naturalness and silence .

Particularly suitable for jazz, vocal, classical and acoustic music.

🎸 Use in Music Applications

Also excellent in:

• vintage and boutique guitar amplifiers,
• V1 position , thanks to low noise & low microphonics .

They offer rich harmonics, great tonal depth and an authentically British character of their origins.

🎯 Note for audiophiles and technicians

This 12AX7 / ECC83 NOS MULLARD Blackburn 1958 – Long Gray Plates – Goalpost / Dual Post Getter – Matched Pair represents:

• a very early Mullard production of Blackburn ,
• one of the rarest and most musically appreciated configurations,
• NOS selection with low noise and contained microphonics,
• first-rate sound, historical and collectible value .

A pair intended for reference systems and demanding collectors , for those who desire the original Mullard sound , rich, natural and deeply emotional, in the full Vacuum Tubes Treasures style.

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Test Results:

Valve tested on AMPLITREX AT-1000 Tube Tester:

• Test Conditions: Va = 250V ; Vg = -2V
• Average 100%: Gm = 1600 ; Ia = 1.2 mA
• Test Result: VERY STRONG

Valve #1:

• Section 1: Gm = 1500 ; Ia = 1.2 mA
• Section 2: Gm = 1600 ; Ia = 1.2 mA

Valve #2:

• Section 1: Gm = 1500 ; Ia = 1.2 mA
• Section 2: Gm = 1500 ; Ia = 1.3 mA

• Microphonics: Low. Tested and approved for use in hi-fi, including phono stages and guitar amplifiers. Also suitable for V1.
• Noise: Low and well-controlled. Silent operation in hi-fi and music amplifiers in the intended positions.
• Balance: The sections are coherent and well aligned, making the valve also suitable for use as a phase inverter in hi-fi and instrumental applications.
• Output Quality: Excellent – ​​Very strong and stable output, no fluctuations.
• Short circuits and GAS: Absent.

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Conditions:

• Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.
  
• Functionality: Fully functional.
  
• Cosmetic condition: Excellent – ​​Excellently preserved lettering, minimal signs of wear. See photos for details.
  

Manufacturing Code:

• f92 B8K→ f9x indicates an ECC83 with the sequential progression of x, where the increment of x indicates the production changes - B8K B → Mullard, Blackburn - 8 (out of three digits) → 1958 - K → November
• f92 B8L→ f9x indicates an ECC83 with the sequential progression of x, where the increment of x indicates the production changes - B8K B → Mullard, Blackburn - 8 (over three figures) → 1958 - L → December

Find out why our valves are different →