KT61 black glass Osram holy grail oval logo EL33 equivalent suit Leak TL10

Description

The KT61 was one of the most used and successful valve back those days.

Used extensively in radio and audio amplification when most set were still mono!

A nice well shaped valve with cup getter  and S shaped spring supporting the mica

This is the fourth set of four pieces KT61 made by OSRAM

LIMITED edition valves of the early 1950s with black glass!

KT61 works at 6.3 Volts filament with Anode and Screen set at 250 Volts

All four KT61 valves have been tested with AVO VCM 163

KT61 Osram 35mA. 34mA. 34mA. 35mA with mutual conductance of 10 and 100% emission