Why tube rectification?


This question is directed at the distinguished members of the forum who design and build tube amps or those who have knowledge of tube amp design. All the tube amps I own/have built us two diodes for rectification. Diodes are cheap, compact and last the life of the amplifier in most cases. Examples include the Dynaco ST-35, the Decware Zenkit1 (which is basically a Decware SE84) and the Elekit TU-8900. All reasonably well respected amps. Yet many of the more expensive amps go with tube rectification, which obviously involves the downside of another tube, more power, more space.

These two competing solutions both supply the basic power to the audio tubes and output transformers, so only indirectly interact with the sound signal. I have not read anything that explains what tube rectification brings to the party. But it must have some upside to offset it's obvious downsides. If I changed over one of the above amps to tube from diode rectification what would I be likely to  hear?

bruce19

Showing 1 response by onhwy61

In guitar amplifiers tube rectification is revered.  The class Fender and later Marshall amps all had tube rectifiers and the sound they produced is a touchstone for virtually every guitar amplifier since.  If you turn up the volume and strike hard on the strings the tube rectifier's relative slowness or sag acts as a compressor and gives a sound that's described as a cream like texture.  Mesa Boogie has offered a Dual Rectifier tube or silicon selectable line of amps for decades.