Ef86 pentode valve edicron ef86 audio frequency amplifying pentode pentode valve b9a base 6 3v heater voltage 200ma heater current 3ma anode current 250v anode voltage a low noise the internal construction is designed to minimise hum and microphony ideally either a dc or balanced centre tap ac heater supply is recommended intended for small signal pre amplifier applications edicron ef86 pentode valve