Fantastic NOS Mazda BELVU 12AX7A SILVER PLATE ecc83 e83cc 7025 special quality 12ax7 made in France

  I am very happy to be able to propose you an other very awesome perfect matched pair of a very rare tube: The Mazda Belvu 12ax7A silver plate.  Special quality tubes.

Test results

tube 1 : 99 % 98 % 

tube 2 : 98 % 93 %

A very unique and superb construction as you can see on the photos. It's a special quality version, they succeeded in reducing microphony to the max on this tube. A jewel of the french tube manufacturing "savoir-faire".
Both made in France in Suresnes.

Highly sought after and rarer version with " open " plate and visible spring.

Not only a super rare and real collector item , it's a superb sounding tube.
It has a very large frequency range, thick sound with very good and responsive bass, excellent and present low mids , higher mids are very detailed, very rich harmonics too.

A wonderful and very musical tube

Many audiophiles would describe them as "3D sound with a lot of air" . It's a grail tube for some audiophile world but also sounds so great in ANY guitar amp.

Superb thick, crystal clear clean sound, and also fantastic in high gain amp.

These tubes are NOS new and have been used just for a few tests.

The auditioning tests revealed ultra low noise and incredibly ultra low microphony for this pair.

Defenitly studio grade, V1 grade !

They've been fully tested, are super strong and nicely balanced, within 6 % !                    

So great for stereo purpose.

I COMBINE SHIPPING ,

 SO PLEASE HAVE A LOOK AT MY OTHER INTEMS AND SAVE .

Shipping price includes full insurance and tracking

These tubes has been tested for

Heater filament test: Short circuit
Heater filament test: Open circuit
Heater filament test: Tolerance check
Heater cathode insulation: Leakage
Heater cathode insulation: Short Circuit
Tests for heater current abnormalities
Amplification factor
Voltage gain
Power gain
Screen grid test
Mutual conductance test
Dual test for double triodes
Emission
Inter electrode leakage
Inter electrode short circuit
Flash-over (arc detection, high voltage breakdown)
Gas ionisation test

with a first tester

and then with a second tester ( Jackson 648S ) for

Leakage

Filament

Circuit

Shorts

Plate

Life test...

The Jackson 648. It is definitely one of my favorite tube testers. While it does not employ a mutual conductance test circuit, it does use an advanced emission circuit that applies separate element voltages to each tube element, and separate load circuits are also used. “These voltages and loads have been carefully selected for each tube to meet most ideally the normal operating condition of the tube.” (Source: 1950 Jackson catalog.)

In my experience, the Jackson circuitry is very effective, and often will surprise you with accuracy that approaches Hickok’s coveted “mutual conductance” test method. ( Source tubesound web site.)

I do my best to test and describe the tubes the best I can.

Note that test results may vary from one tester to an other so this must be taken as an indication, although my <jackson is regularly tested for calibration.

 Photos are part of the description you get what you see.

Thank you for your interest.