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MULLARD

7025 / 12AX7 / ECC83 Webcor by Mullard Blackburn 1962 - Short Gray Plates - Halo Getter - Balanced Section

7025 / 12AX7 / ECC83 Webcor by Mullard Blackburn 1962 - Short Gray Plates - Halo Getter - Balanced Section

₩186,000 KRW
₩186,000 KRW
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7025 / 12AX7 / ECC83 Webcor by MULLARD – Blackburn (Great Britain) 1962
Short Gray Plates – Halo Getter – Balanced Section – Low Noise & Microphonics

AMPLITREX Tested – STRONG – Low Noise & Microphonics – Vintage GT. BRITAIN MULLARD Production

Test Results:

Tube tested on AMPLITREX AT-1000 Tube Tester:

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

Tube :

  • Section 1: Gm = 1500 ; Ia = 0.8 mA
  • Section 2: Gm = 1500 ; Ia = 0.8 mA
Additional Tests Performed:
  • Burn-in / Stability Test: 48h – OK
  • Microphonics: Very Low. Tested and suitable for use in hi-fi equipment and guitar amplifiers, including the most sensitive audio stages.
  • Balance: Excellent - The sections are consistent and well-aligned, making the tube suitable for use as a phase inverter in hi-fi and instrument applications.
  • Emission Quality: Strong – Strong and even emission, suitable for any application.
  • Short Circuits and GAS: None.

Description

Selected vintage specimen of 7025 / 12AX7 / ECC83 Webcor by Mullard, produced at the historic Mullard factory in Blackburn, Great Britain, in December 1962. Originally marketed under the American Webcor brand, this tube retains the authentic British construction of Short Gray Plates with Halo Getter, a feature of Mullard production from this period. The original code I61 B2L5 documents its production identity and date, making it particularly interesting for audiophiles and collectors looking for authentic vintage Mullard tubes.

The measurements performed with the Amplitrex AT-1000 highlight an excellent electrical balance, with perfectly identical values in the two sections. The transconductance reaches 1500 µmhos for both triodes, corresponding to 93.75% of the nominal reference of 1600, while the anode currents are uniform at 0.8 mA, compared to the reference of 1.2 mA. Although the anode current is lower than the nominal value, the perfect correspondence of the measurements confirms a remarkable internal symmetry, particularly appreciated in applications requiring electrically balanced sections.

The tube has passed 48 hours of burn-in and stability testing, maintaining a strong and even emission, without fluctuations, short circuits, or the presence of gas. The tests also confirmed very low noise and microphonics levels, making this specimen particularly suitable even for the most sensitive audio stages, where silence and stability are of particular importance.

The Mullard ECC83 Blackburn tubes are traditionally appreciated in hi-fi preamplifiers, compatible phono stages, and guitar amplifiers, even in the V1 position and in phase inverter circuits. The British Mullard production of the 1960s is sought after by audiophiles for a musical presentation generally described as warm, full-bodied, and refined, with a midrange rich in nuances, tonal naturalness, and pleasant expressive fluidity.

The value of this specimen lies in its authentic 1962 Mullard Blackburn production, its original Short Gray Plates construction, the perfect balance of the sections, and its selection for very low microphonics. The well-preserved silkscreening, very good cosmetic condition, and legible manufacturing code complete a vintage tube of particular interest. An authentic Webcor by Mullard Blackburn, carefully tested and selected, for those who wish to rediscover the charm of historic British thermionic production through a specimen with documented electrical characteristics.

Condition:

  • Condition: Vintage Tubes - Tested and perfectly functional. Supplied in our custom box for optimal protection. 
  • Functionality: Perfectly operational.
  • Cosmetic condition: Very Good – Markings clearly legible with slight signs of age. See photos for details.

Manufacturing Code:

  • I61 B2L5→ I6x indicates an ECC83 with the sequential progression of x, where the increment of x indicates production changes - B2L5 B → Mullard, Blackburn - 2 (out of four digits ) → 1962 - L → December - 5 → fifth week of the month

Discover why our tubes 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.

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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.

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