Perfect 1973 NOS NIB MULLARD Blackburn ecc83 12AX7 matched pair CLOSE CODE UK EXTRA STRONG Philips label, I63 model, best preamp tube, Orange Hiwatt Marshall

Hi, I'm happy to propose you for sale a superb and perfect NOS NIB Blackburn Mullard ecc83 matched pair with quite close date code. Fully tested including for sound, noise floor and microphony with most excellent results. Definetely V1 one, mastering grade.
Tests results :

Tube 1 111 %   115 %

Tube 2 116 % 115 %

So nicely matched within 5 % which is excellent for stereo use.

They are new unused and over full new specs.

Both tube same exact I63 model with " silver nickel" rods . One was made the third week of july 1973 and the other the first week of decembre 1973.

Both tubes were made at the same famous Mullard Blackburn Factory, UK.
The tubes bears the white Philps label as meant for french export.

Printings are perfect as well as factory codes.
The tubes are new, perfect top condition and provided with their original Philips boxes.

 Mega strong, well balanced and matched.

Great for  some stereo purpose and an absolutely excellent choice your favorite bass or guitar amp.
Rare opportunity to get such a nice specimen of perfect matched pair of I63 Mullard  .

Warm, punchy, the lovely Mullard mids and tone. Big sounding tube with rich and silky highs and great harmonics..
Pure British jewel.

Let your Marshall, Orange, Hiwatt or whatever get its full original tone . Hear and feel the difference.

I COMBINE SHIPPING ,

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

Shipping cost includes tracking and insurance.

This tube 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 regulary tested for calibration.

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

Thank you for your interest.