Rectifier circuit design

[Nihon Jim]

Greetings Boogie Board. I'm new to this Board and to Mesa amps. In an effort to try something different I'm readying myself to pull the trigger on a three channel Dual Rectifier. Not sure if it will be a Solo Head or one of the newer 100 watt heads with the 50/100 option.

My question regards the theory of design of the rectifier circuit. This will be my first foray into an amp with a tube rectifier circuit (in addition to a diode rectifier). All of my other amps (many Marshalls, a few Fenders, Blackhearts, Black Stars and Vox - all tube amps) are diode rectified.

My question - why are there two 5U4 tubes in the dual rectifier and three 5U4 tubes in the triple rectifier? Is one 5U4 able to supply the required tube voltage to only two 6L6s at a time? And therefore the additional 5U4s are required?

Many thanks in advance.

 

[JMMP]

Welcome to the board!

You are correct in your analysis of the number of rectifier tubes.
Tube rectifiers are more limited to how much current they can pass in a given amount of time in comparison to a diode. Also, they do not instantly provide their maximum current throughput. This is the reason having two different rectification methods on one amp makes any sense. The difference is felt as well as heard.