AUDIO VALVES: 6X4 CV493 CV4005 EZ90 U78 RECTIFIER

The 6X4 is a miniature HT rectifier following the normal pattern for a full wave device in that a common cathode is employed.

At 325-0-325 input to the rectifier this will give an HT rail higher than is required for most domestic receivers. Use for audio amplifiers and small transmitters is most probable, or driven at 250 volts for radio receivers. The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 59 mm tall.

These valves saw duty in many of the smaller classic hifi amplifiers and guitar amplifiers, however, here's a list of some exciting exotica that also uses them:-

Audio Note DAC 1.2

Eastern Electric
KONDO KSL M7 preamp
LAMM LP2 Deluxe Phono
Musical Surroundings
Sears Silvertone 1482 Guitar amp 1965-1966
Wright WPP200C
YS Audio Symphonies + preamp