Mesa/Boogie has many amps with dual or triple rectifier tubes, but why would they do that? For cases where you need more current than one can provide, that's understandable. But, even the lower-power ones have two big rectifier tubes.
Do you think it's for tone reasons?
As I understand it, the "sag" of rectifiers is desireable (I agree), but when you use two or three, it just lessens the "sag". So if they want less sag, why not just use a bridge with diodes? (they have a switch for this as well).
Multiple Rectifiers? Why?
Moderators: pompeiisneaks, Colossal
Re: Multiple Rectifiers? Why?
Hey James!
That's a very good question! I wasn't really sure which models of the small Mesa amps have the two parallel rectifier tubes, but I guess in theory that it might have something to do with Boogie's propensity to use large plate filter capacitance (110uF, usually). It might also be just to compromise between the 5U4's sag and a SS rectifier, though I guess the critic in me tends to consider a third reason.
Imagine that you were somehow able to convince the U.S. government that your backyard is not now, nor ever was, officially part of the country and it is therefore a new, autonomous nation. You'd probably phone all your friends and tell them about it, right?
I think that a large part of why Boogie might use their "patented dual rectifier technology", even if it's not technically required, might just be a question of marketing/branding. Like many others, I'd heard of Randall Smith's somewhat questionable dealings with the Patent and Trademark Office before looking them up to try to better answer your question, but I never really appreciated what could slip through the cracks of the review system. I mean, he was finally awarded the patent for two channel amplifiers in Feb. 2003!
I wonder if this guy is of any relation.
Matt
That's a very good question! I wasn't really sure which models of the small Mesa amps have the two parallel rectifier tubes, but I guess in theory that it might have something to do with Boogie's propensity to use large plate filter capacitance (110uF, usually). It might also be just to compromise between the 5U4's sag and a SS rectifier, though I guess the critic in me tends to consider a third reason.
Imagine that you were somehow able to convince the U.S. government that your backyard is not now, nor ever was, officially part of the country and it is therefore a new, autonomous nation. You'd probably phone all your friends and tell them about it, right?
I think that a large part of why Boogie might use their "patented dual rectifier technology", even if it's not technically required, might just be a question of marketing/branding. Like many others, I'd heard of Randall Smith's somewhat questionable dealings with the Patent and Trademark Office before looking them up to try to better answer your question, but I never really appreciated what could slip through the cracks of the review system. I mean, he was finally awarded the patent for two channel amplifiers in Feb. 2003!
I wonder if this guy is of any relation.
Matt
Re: Multiple Rectifiers? Why?
One of Mesa's large amp heads has THREE rectifiers.
I saw them in the back, and they were huge, and have the glass envelope with a bulge in the centre. At first I thought they were the power tubes, but there was only three. The 4 EL34's were there, so the 3 have to be rectifiers.
HMM. I don't know what's up with that.
I am just thinking that if you wanted less sag, or more current, you could use a bigger/better single rectifier.
I saw them in the back, and they were huge, and have the glass envelope with a bulge in the centre. At first I thought they were the power tubes, but there was only three. The 4 EL34's were there, so the 3 have to be rectifiers.
HMM. I don't know what's up with that.
I am just thinking that if you wanted less sag, or more current, you could use a bigger/better single rectifier.
Re: Multiple Rectifiers? Why?
I could be wrong, primarily because I have never been a Mesa/Boogie user, but I thought the multiple rectifiers in the Dual Rectifier and Triple Rectifier amps were selectable, not in concurrent parallel or series operation. In other words, you are not using two or more different rectifiers at the same time, but you have the option of choosing between a solid-state recitifier or a tube rectifier in the Dual Rectifier for different touch responsiveness of the amp. In the Triple Rectifier, you have a choice between a solid-state diode system and two different rectifier types. I suppose this gives you the option of choosing the tightness or sag of your power supply. It might come in handy if you play blues gigs on Tuesday night and flick a switch to play metal on Friday. 
Like I said, I could be wrong but I thought that was the idea behind those amps.
Now, some old Fender tweed Twin amps used dual rectifiers at the same time in order to lessen the voltage drop across a single rectifier, stiffen the power supply and raise the B+. But this dual-rectifier approach was before the age when solid-state rectifiers became common in guitar amps to achieve the same ends.
Like I said, I could be wrong but I thought that was the idea behind those amps.Now, some old Fender tweed Twin amps used dual rectifiers at the same time in order to lessen the voltage drop across a single rectifier, stiffen the power supply and raise the B+. But this dual-rectifier approach was before the age when solid-state rectifiers became common in guitar amps to achieve the same ends.