This high impedance amplifier triode is designed specifically for audio use and has a high amplification factor of 100.
This valve is found in todays designs of hi-fi audio amplifiers. In the classic Mullard designs of the 1950’s and 1960’s the valve’s two halves were used as second stage amplification and cathode coupled phase splitter. The phase splitter being required so that the push-pull output stage was driven correctly.
The envelope is 21 mm in diameter and the average diameter for B9A valves is 20 mm. Length excluding pins is 48 mm.
The Ei EL84 is a power amplifier pentode designed for use in the audio frequency power output stage of television and radio receivers and in high fidelity amplifiers.
The performance curves for each tube produced are stored in the computer which controls the test sequence. This same computer then performs the matching algorithm, working from the entire single tube inventory, to find the best matched pair for each order.