Vintage MULLARD 12AX7 ecc83, very strong, fully tested, magic for Orange Hiwatt Marshall, preamp.

Here for sale a nice MULLARD 12AX7 ecc83 l63 model made probably in mid or late 60's as old shield logo whit print.  at Blackburn Factory, in the UK. Inforfortunatly the date code is erased, but still L63 code and the B code can be guess in some good light even if not obvious.  Other printing is nice.

VERY STRONG
not perfectly balanced but perfect for V1
Tests results   105 %   132%
 very few use.
Copper post, ring getter, print is perfect, sound is huge, sweet and warm ! Pure british jewel.

Let your Marshall, Orange, Hiwatt or any nice amp get its full original tone . Hear and feel the difference. Supplied in new white box.

I COMBINE SHIPPING ,

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

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
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.