Why is kenotron power for a tube amplifier a good thing?

Tube amplifiers have long been recognized by audiophiles and professionals alike for their exceptional sound quality. One of the key elements determining the performance of such an amplifier is its power supply. Among the various options, the kenotron power supply is particularly notable.

A kenotron is a type of electrovacuum diode used to rectify alternating current into direct current. In tube amplifiers, kenotron power supplies are valued for their ability to provide a soft and stable voltage, which in turn contributes to outstanding sound quality: natural timbres, deep bass and clean treble. Thanks to their features, kenotron power supplies add the warmth and "tube-like" character that fans appreciate.

Solid state rectifiers are an alternative to kenotron power in tube amplifiers. These use solid-state diodes or power transistors to rectify current. While these devices may be more reliable and cheaper to manufacture, they often introduce additional distortion and rob the sound of that "tube" warmth.

Various types of tubes are used in tube amplifiers, including power tubes (e.g. EL34, KT88, 6L6), preamplifier tubes (12AX7, 12AT7), and of course kenotrons (e.g. 5U4G, EZ81). The choice of tube depends on the desired sound characteristics and amplifier design.

Many tubes produced during the Soviet era are still appreciated for their high quality and characteristic sound. Among them are GU-50, 6P14P, 6P3S, 6Zh1P and kenotrons like 5Ts3S. These tubes are perfectly suitable for use in modern tube amplifiers and can often serve as a worthy alternative to their Western analogs.

The kenotron power supply provides a soft start when the amplifier is turned on, which reduces mechanical stress and contributes to the longevity of the tubes. In addition, the kenotron is capable of smoothing out voltage ripple, which is especially important for maintaining sound clarity.

Some of the best known kenotron-powered amplifiers include the McIntosh MC275, Audio Note Ongaku and Manley Neo-Classic SE/PP. These units have established themselves in the audiophile world for their outstanding sound and exceptional performance.