EF86
The EF86 electron tube is a small signal pentode with low noise and is still used in audio tube amplifiers today. The tube was developed in 1954 by the German tube manufacturer Valvo - a subsidiary of the Dutch Philips group . It is the successor to the EF40 and has a Noval base.
General
Together with the presentation of further new miniature Noval tubes, the British company Mullard published a then novel amplifier circuit concept, the Mullard 5-10 , with which the performance potential of the new generation of tubes could be fully exploited.
Special design features include a bifilar winding of the heating wire in the area of the cathode in order to ensure a minimal stray field on the cathode tube even with inexpensive alternating current heating ; Nevertheless, the tube heating of the EF86 is preferably operated with direct current in the highly sensitive pre-stages to optimally avoid hum.
Typical areas of application for the EF86 were microphone preamplifiers and playback amplifier preamps in tape recorders , but the famous Vox AC30 guitar amplifier was also fitted with the tube in the input stage.
The 50 mm high EF86 is still being manufactured today (2010) and is currently used in top-quality, professional large-diaphragm studio condenser microphones from the renowned Berlin company Neumann and Microtech Gefell GmbH .
With the EF83 there is a parallel type with an exponential characteristic .
Technical specifications:
- Maximum anode voltage, U a : 300 V
- Anode power dissipation , P a : 1 W
- Maximum screen grid voltage, U g2 : 200 V
- Cathode current, I k : 6 mA
P series
The parallel type PF86 with 0.3 A series heater was z. B. used by Philips as a Miller integrator in the vertical deflection circuit of televisions of the 1950s and 60s. Except for the different heating data and the missing bifilar design of the filament, it is interchangeable with the EF86. The different filaments also allow a simple visual differentiation of the two rows.
Web links
- frank.pocnet.net - Data sheet for EF86 (PDF file; 318 kB)
- frank.pocnet.net - Data sheet for EF83 (PDF file; 278 kB)
- frank.pocnet.net - Data sheet for PF86 (PDF file; 132 kB)
Individual evidence
- ↑ Archived copy ( Memento of the original from April 12, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
