The electron tube EF86 is a small sign Alps death with low noise and is also still used today in audio tube amplifiers. The tube was in 1954 by the German tube manufacturer Valvo - developed - a subsidiary of the Dutch group Philips. It is the successor model of the EF40 and has a Noval socket.


Along with the idea of further new miniature Novalröhren published the British Mullard a then novel amplifier circuit concept, the Mullard 5-10, with the performance potential of the new generation tube could be exploited maximum.

Special design features are in a bifilar winding of the filament in the cathode in order to ensure a minimal stray field on the cathode tube even at a low cost AC Heating - yet the tube heating the EF86 for optimal ripple prevention is preferably operated with direct current in highly sensitive precursors.

Typical areas of EF86 were Mikrofonvorverstärkerstufen and playback amplifier precursors in tape recorders, but also the famous guitar amplifiers Vox AC30 was loaded in the input stage with the tube.

The 50 mm high is EF86 (2010) still produced today and currently used in most professional studio large diaphragm condenser microphones of the renowned Berlin Neumann company or the company offshoot Microtech Gefell GmbH.

With the EF83 exists a parallel type with Exponentialkennlinie.


  • Maximum anode voltage Ua: 300 V
  • Anode dissipation, Pa.: 1 W
  • Maximum screen grid voltage, Ug2: 200 V

P- series

Parallel Type PF86 with 0.3 A series heater was used as a Miller integrator in the Vertiakalablenkschaltung of televisions of the 50s, for example, Philips. It is interchangeable except for the different heating data and the lack of bifilar interpretation of the filament with the EF86. The different filaments allow for easy visual distinction between the two rows.