Very rare 50's NOS Sylvania 5Y3 GT 5Y3GT round BLACK PLATE, SQUARE GETTER balanced and super STRONG.

Here for sale a quiet rare ( especially in Europe) 50's Sylvania 5Y3 GT round, welded, black plate, square getter, black base. Beautiful and best construction.
NOS very well balanced and super strong.
 Made in the USA, by Sylvania. Best rectifier tube

Tests results   113 %   116 %

Sold as new or very few use.

Fully tested on 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.

Private sale so no guarantee or return please.

But if any problem (never happened yet ) please contact me first.