Super rare NOS NIB SVETLANA winged =C= 12AX7 ECC83 SILVER plate BOX PLATE like CV4004 XTRA strong balanced

For sale a super rare, super strong NOS NIB Svetlana winged =C= ecc83 , wellbalanced and extra strong well well over full specs. New, never used, perfect condition.

Tests results : 139 % 131 %

Super rare silver box plate ! like the military CV4004 Mullard production but with "silver " plate and cupboard getter. Non copper rods. Rare pur copper thick wires to pins construction. (see photos)

Black winged =C= label.

Very interesting and great sounding tube . Very transparent but fat with good low mids ,but not muddy. Kind of fat and bright but not harsh. Very sensitive reactive under the pick. You really 've got the sound of your strings and the feel of it.

I know some Svetlana ecc83 are known to be often microphonic, but don't worry this tube has been fully tested and microphony is ok :)

This is probably the last I will ever sell...

Get the best of your amp . Hear and feel the difference of tubes of the golden era.

I COMBINE SHIPPING ,

 SO PLEASE HAVE A LOOK AT MY OTHER INTEMS 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
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.