P27/500 Tungsram balloon with special filament arrangement PX25 PP5/400 matched pair

Description

AudioMagical introduces most of all PX25 type made from 1932 up to the 1960s

The PX25 is a output valve like a PX4 but with higher output and Anode Voltage.

Pair Tungsram P27/500 balloon shape which are direct equivalent of the  PX25 Marconi Osram.

The P27/500 is a power amplifying valve of extremely high efficiency designed with a large power handling capacity to supply considerable undistorted volume. 

They intended for use in the last stage of Low Frequency Amplifiers where provision is made for adequate high tension supply. When operating the P27/500 valve, arrangement should be made for sufficient air circulation to prevent over-heating

Filament Voltage 4

Filament Current 2 amps 

Anode Volts 400

Grid Volts -31

Anode Current Average 62

Anode Dissipation 25 Watts

Mutual Conductance  mA/V 8

 

Tested with AVO VCM 163

P27/500 Tungsram  {1} 51mA 100% emission mA/V 7

P27/500 Tungsram  {2} 52mA 100% emission mA/V 7

Supplied with original boxes