picture of a late PX4

PX4 - Magic in a Bottle

Find out more about the PX4 and some of its friends.

PX4 - the best audio amplifier valve?

The PX4 was designed by Marconi-Osram in the 1920's and many audio enthusiasts believe it to be the finest-sounding power triode ever made. Properly installed in a single-ended triode amplifier driving efficient loadspeakers, the PX4 produces a sweet and beguiling sound whilst preserving the finest detail.

Main Features

  • Directly-heated cathode
  • 300v anode voltage
  • 50 mA current
  • 4 watt power output

Valve or Tube - What's in a Name?

In England we call a valve a valve (or [slang] a bottle): in the United States it's a tube (pronounced toob). Does it matter? No. Also for anode (England) read plate (United States).

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