NOS-Tested Mazda MBLE EF86 6267 Matched Pair Low Noise Mesh O-Getter

Listing details

NOS-tested M.B.L.E. Brussels EF86 / 6267 matched pair

This is a carefully selected pair of vintage EF86 / 6267 low-noise audio pentodes manufactured by M.B.L.E. in Brussels, Belgium, within the Philips/Mazda production family.

The pair is electrically impressive and cosmetically understated. It is intended for the buyer who values verified performance, close matching and authentic European construction more than decorative glass printing.

Both tubes were marked NOS when selected from inventory. Those exterior inventory markings were removed during careful cleaning before the final photographs were taken. Both tubes test at or above the Triplett 3444 average-new reference.

The exact numbered tubes shown in the photographs are the tubes the buyer will receive.

Why these two tubes were paired

These tubes were selected together because they share closely matching construction:

Fine diamond-pattern silver mesh shields

Matching polished silver upper internal cuffs

Top halo/O-getters

Matching getter-flash patterns

Closely matching electrode structures

Matching support geometry

B9A nine-pin miniature bases

Closely matching envelope dimensions

They are also closely matched electrically.

Triplett 3444 test results

Tube #1

Transconductance: 2,150 µmhos

Plate current: 2.7 mA

Tube #2

Transconductance: 2,050 µmhos

Plate current: 3.0 mA

Triplett 3444 reference

Minimum reference: 1,300 µmhos

Average-new reference: 2,000 µmhos

Both tubes test at or above the Triplett average-new reference.

Their transconductance readings differ by only 100 µmhos. Based on the pair average of 2,100 µmhos, the measured transconductance spread is approximately 4.8%.

The pair was matched primarily for:

Transconductance

Internal construction

Manufacturer and production family

Low-noise performance

Freedom from detected microphonics

Both tubes were individually verified:

Low noise

No microphonics detected

Stable measured performance

Factory and production codes

Tube #1

Type code: 8YC

Factory/date code: L9G1

8Y identifies the EF86 type

L identifies M.B.L.E., Brussels

The code is consistent with the first production week of July 1969

Tube #2

The original type-code line is no longer visible

The lower factory/date code is faint

The visible characters appear consistent with L9G1

Its internal construction closely matches Tube #1

The Philips factory-code reference identifies L as M.B.L.E., Bruxelles/Mazda. Its newer date format uses G for July and the final digit for the production week.

Cosmetic presentation

The original commercial brand stencils are no longer present on the glass. Tube #2’s etched production code is faint, and the pins show normal vintage surface aging.

These presentation details are clearly shown in the photographs and are reflected in the asking price.

In return, the buyer receives a carefully documented pair with strong measured performance, close transconductance matching, verified low-noise operation and highly consistent internal construction.

Applications

The EF86 / 6267 is a high-gain, low-noise pentode used in selected:

Guitar-amplifier input and preamplifier stages

Vintage and modern EF86-equipped amplifiers

Phono and audio preamplifiers

Studio and broadcast equipment

Microphone and recording circuits

High-fidelity audio equipment

The EF86 is associated with selected Vox, Matchless, Dr. Z, Quad and studio-preamp applications. Equipment compatibility should always be verified before installation.

Reported sonic character

Vintage Brussels-made Philips-family EF86 tubes are often sought for a presentation described by listeners and dealers as:

Smooth and clear

Sweet through the midrange

Dimensional and spacious

Natural with voices and acoustic instruments

Detailed without excessive sharpness

Sonic results depend on the circuit, equipment and complete audio system.

Included

M.B.L.E. Brussels EF86 / 6267 Tube #1

M.B.L.E. Brussels EF86 / 6267 Tube #2

New white replacement box marked #1

New white replacement box marked #2

VTubeAudio test documentation

Exact tubes shown in the listing photographs

The box numbers correspond directly with the measurements and photographs.

Carefully packed for secure shipment.

Results reflect measured performance on the Triplett 3444 at the time of testing. Exact pair documented in this sales listing.

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