Dual and triple rectifiers- what's the effect?

[kwk13]

What does a triple rectifier or dual rectifier do to an amp tonewise? I know Mesa uses this type setup but how would the amp sound if it didn't have the multple rectifiers? Might be a stupid question but I was just wondering if this was just marketing hype or how the tone changes and how.

Thanks,

Keith

[JPW]

What does a triple rectifier or dual rectifier do to an amp tonewise? I know Mesa uses this type setup but how would the amp sound if it didn't have the multple rectifiers? Might be a stupid question but I was just wondering if this was just marketing hype or how the tone changes and how.

Thanks,

Keith
There is no multiple rectifiers. There is only tube or solid state. Dual and triple are just COOL names for these amps. Maybe it's because the duals have 2 rectifier tubes and the triples have 3 rectifier tubes. You need 1 rectifier for every pair of power tubes you got, wether you select tube or solid-state rectification. Thats why the single rectifiers are called what they are. There is no switch in the back to select a rectifier option. They are solid state rectified and not tube rectified.

[rockon1]

There is no multiple rectifiers. There is only tube or solid state. Dual and triple are just COOL names for these amps. Maybe it's because the duals have 2 rectifier tubes and the triples have 3 rectifier tubes. You need 1 rectifier for every pair of power tubes you got, wether you select tube or solid-state rectification. Thats why the single rectifiers are called what they are. There is no switch in the back to select a rectifier option. They are solid state rectified and not tube rectified.


Well wouldnt a choice between SS and tube rectification on the mesa be "mulitple" rectifiers? Mesa 's DO has a switch on the back for selecting tube or SS rectification.

[Johnny Z]

Just another way to sell more amps.

Like how many rectifiers does it take to make a good amp? Most good amps only need one. And most 100 watt amps are solidstate.

[rockon1]

Well to attempt to answer the original question- I think using a tube rectifier may bring the headroom and overall wattage down a bit. It may make the amp feel a bit more touch sensitive by adding a bit of sag to the sound-mostly at high levels. Perhaps the experts around here will be able to elucidate on this. There will be a difference and ,no I dont think its marketing hype-its more tonal choice.

[nateG.]

I know that when Mesa Rectifiers came out, there weren't many (any?)large amps with rectifier tubes, so it was a cool new thing at the time. Paralleling rectifier tubes will reduce the voltage drop inherent in tube rectifiers, so I assume that having two or more was a way to keep some sag and compression, but have enough firmness that a 100 watt high gain head would probably need. Tube rectifiers "sag" when a high current demand is needed, like whacking out an open E chord on high gain. Randall Smith was probably trying to accomplish the best of both worlds by having multiple rectifier tubes.

[scopeboy]

Triple recto = 3/2 the hype of a dual recto ;-) I can't think of any other reason to use three rectifier tubes.

[JPW]

Well wouldnt a choice between SS and tube rectification on the mesa be "mulitple" rectifiers? Mesa 's DO has a switch on the back for selecting tube or SS rectification.
I ment there is NO SWITCH on the back of the Single Rectifier. I used to own a Dual rectifier for 6 years. I know about their "Rectifiers".

[Random Hero]

Tube recto sounds great for lead tones, especially on the 2ch models. Orange/Vintage/Bold/Tube just sings.

[sosomething]

If you want to really understand the tonal diff. between tube and solid-state rectification, just plug into a Recto model and flick the switch. The difference is pretty apparent.

[John Phillips]

There is no multiple rectifiers. There is only tube or solid state. Dual and triple are just COOL names for these amps. Maybe it's because the duals have 2 rectifier tubes and the triples have 3 rectifier tubes. You need 1 rectifier for every pair of power tubes you got, wether you select tube or solid-state rectification. Thats why the single rectifiers are called what they are. There is no switch in the back to select a rectifier option. They are solid state rectified and not tube rectified.

Just another way to sell more amps.

Like how many rectifiers does it take to make a good amp? Most good amps only need one. And most 100 watt amps are solidstate.
Wow... I can't believe that people would post this sort of thing with clearly no experience of the amps in question.

The Mesa Dual and Triple Rectifiers use three different combinations of what 'Dual Rectifier' can be taken to mean, and all of them do practical things that aren't just 'a way to sell more amps'.

In the actual Dual Rectifier model - which is a 100W amp, BTW - there are two rectifier tubes, because one alone will not supply enough current for a 100W output section. There is also a switch to select tube or solid-state rectification, which has a noticeable effect on the dynamics and some effect on the tone. (It's also a useful way to carry an 'onboard backup' in case a rectifier tube fails.) So it's a 'dual rectifier' in two ways.

(The Triple Rectifier is exactly the same but uses three rectifier tubes since it needs enough current to supply a 150W output section. There is only one solid-state rectifier in both these amps, because they're easily capable of supplying enough current.)

In the Maverick and other lower-powered models, there is only one rectifier tube, but it's still a dual rectifier amp because you can select between tube or solid-state rectifiers, in the same way.

Thirdly, in the Blue Angel there is one rectifier tube, and it isn't switchable (I think it might have been on the earliest models). But it's still a Dual Rectifier because it uses separate tube (for the power stage) and solid-state (for the preamp) rectifiers. The purpose of this is to guarantee that the preamp has greater headroom than the power stage, so the power stage clips first.

No offense intended, but if you're going to post information about amps, please at least make sure you have the slightest idea what you're talking about... or is it that you just don't like Mesa amps? :rolleyes:

[Johnny Z]

Wow... no offense intended, but I can't believe that people would post this sort of thing with clearly no experience of the amps in question.

The Mesa Dual and Triple Rectifiers use three different combinations of what 'Dual Rectifier' can be taken to mean, and all of them do practical things that aren't just 'a way to sell more amps'.

In the actual Dual Rectifier model - which is a 100W amp, BTW - there are two rectifier tubes, because one alone will not supply enough current for a 100W output section. There is also a switch to select tube or solid-state rectification, which has a noticeable effect on the dynamics and some effect on the tone. (It's also a useful way to carry an 'onboard backup' in case a rectifier tube fails.) So it's a 'dual rectifier' in two ways.

(The Triple Rectifier is exactly the same but uses three rectifier tubes since it needs enough current to supply a 150W output section.)

In the Maverick and other lower-powered models, there is only one rectifier tube, but it's still a dual rectifier amp because you can select between tube or solid-state rectifiers, in the same way.

Thirdly, in the Blue Angel there is one rectifier tube, and it isn't switchable (I think it might have been on the earliest models). But it's still a Dual Rectifier because it uses separate tube (for the power stage) and solid-state (for the preamp) rectifiers. The purpose of this is to guarantee that the preamp has greater headroom than the power stage, so the power stage clips first.

If you're going to post information about amps, please at least make sure you have the slightest idea what you're talking about... or is it that you just don't like Mesa amps? :rolleyes:

You're assuming I don't know anything about Mesa amps, assuming is foolish. I've owned 2 Mesa's one was Dual Rect, it flat out sucked for clean tone and was given to me by a well known guitarist as a fixer upper, when I was still working on amps as a Roady. I got it working for him and he didn't want it back, didn't like it. Sure you can play with the switching and get a little tube sag but so what, if that's what you want buy one. There are way better ways to get tone and improve your playing skills. I still think they are a usless POS, I would rather have better built amp with just one good rectifier even if it's a solidstate.

[John Phillips]

There are way better ways to get tone and improve your playing skills.This again... if you really think that's all it's about, why bother posting on a technical thread?

How an amp sounds and how well you play aren't related, anyway. The amp's tone is what it is, the player just uses it. Plenty of players get good tones (including clean) out of them... even if you couldn't.

OK, so you didn't like your Mesa amp. Is that a good reason to post (apparently) ignorant comments about the value of one of their design elements?

FWIW, a couple of vintage Fender amps use dual rectifiers too.

[boogieplaya]

John, dont waste your time.There are other people more deserving of your knowledge..i.e. people that WANT to learn.

[scopeboy]

Horses for courses. The Mesa Rectifier amps are excellent at what they do. If you don't like the style of music they are intended for, you will hate them. I remember when I was a student, the dual recto was my dream amp. I couldn't afford it though, so I set out to build a tube amp that sounded like one. I have no idea whether I succeeded, but along the way I discovered how much fun it was to build amps instead of buying them.

[Random Hero]

Horses for courses. The Mesa Rectifier amps are excellent at what they do. If you don't like the style of music they are intended for, you will hate them. I remember when I was a student, the dual recto was my dream amp. I couldn't afford it though, so I set out to build a tube amp that sounded like one. I have no idea whether I succeeded, but along the way I discovered how much fun it was to build amps instead of buying them.

It was my dream amp too. Then I got a 3ch head and kinda liked it. After that, I traded it for a 2ch blackface and :eek: it was awesome.

[John Phillips]

What's ironic is that the trademark massive, resonant, scooped crunch that they do so well has become called a 'rectifier' (or even 'rectified') sound, when it has almost nothing to do with the rectifier and almost everything to do with the preamp... :)

[Jef Bardsley]

You're assuming I don't know anything about Mesa amps, assuming is foolish.
No assumption is necessary - you've made the depth of your knowledge abundantly clear.

I was still working on amps as a Roady.
There are better ways to improve your technical skills. Being rude to one of the greatest teachers on the planet isn't one of them.

If John can't add to your knowledge, perhaps I can add to your vocabulary - next time, try the simple phrase, "I stand corrected."

[scopeboy]

The name does cause a lot of confusion. More or less everyone I ever talked to about amps does seem to think that a "rectifier" is some kind of magic gizmo that gives the Mesa rectifier amps their trademark sound, that guys with baggy shorts and tattooed ankles go wild for. I once tried explaining it to a musician with no success.

[boogieplaya]

adios

[kwk13]

So, the terms Dual and triple rectifiers in the Mesa line don't necessarily have much to do with the type of tone the amp gets (aside from the solid state vs. tube rectification), the "Mesa sound" really has more to do with the preamp? I think that's what I understand so far from theoutput of the thread. The multiple rectifiers are more to give a choice between solid state vs. tube rectifier tone and the number of rectifiers needed to handle the power output?

Thanks for all the help on this stupid question!!

[boogieplaya]

its really not a difficult concept to understand..

[AL30]

Well that was ... entertaining.

Anyway - why the need for the Dual Rectification? I read the posts and your comment on supplying enough current. So, why isn't there enough current? Couldn't this be remedied? Is this a design flaw (I don't mean that to be degrading) or is it actually necessary?

AL

[boogieplaya]

its just another tone/feel to the amp to add to its versatility.

[Jef Bardsley]

So, the terms Dual and triple rectifiers in the Mesa line don't necessarily have much to do with the type of tone the amp gets (aside from the solid state vs. tube rectification), the "Mesa sound" really has more to do with the preamp? I think that's what I understand so far from theoutput of the thread. The multiple rectifiers are more to give a choice between solid state vs. tube rectifier tone and the number of rectifiers needed to handle the power output?

Thanks for all the help on this stupid question!!
Right. The rectifier choice has more to do with the attack envelope than the tone, and you'll get the same difference on any amp.

[scopeboy]

Yes kwk13, that is the way I always understood it, anyway.

As for why they use multiple tube rectifiers, I don't think it is easy to get a single rectifier tube that will handle enough current to drive a 100 watt or 150 watt amp. There are only a few types of rectifier tube still in production, and AFAIK the strongest one you can get is the 5AR4/GZ34, which still really is only enough for a 50 watt amp.

So if Mesa wanted a 150 watt amp with tube rectification, they had to use three rectifier tubes, like a previous poster said.

[John Phillips]

Yes, exactly - it's because of the current rating of rectifier tubes. A 5U4 - the type Mesa use - is limited to 275mA. (GZ34s are 250mA, 5Y3s are only 125mA for example.)

A 50W amp draws approximately 250mA at full power (bearing in mind that a typical amp is no more than 50% efficient, so the power supply needs to provide 100W, and at a voltage of 400V that would require exactly 250mA - the real figures will vary slightly depending on the voltage and the exact efficiency), so a single 5U4 or GZ34 is only enough for a 50W amp. A 100W amp needs two, and a 150W amp needs three. It doesn't matter how many power tubes are used to produce the power - a 2x6550 amp can produce 100W too, and would still need two rectifier tubes. A 4xEL84 amp only needs one because it's limited to around 45W at most.

[iggs]

What's ironic is that the trademark massive, resonant, scooped crunch that they do so well has become called a 'rectifier' (or even 'rectified') sound, when it has almost nothing to do with the rectifier and almost everything to do with the preamp... :)

Even more ironic is the fact that most DualRec guys don't even use the tube recto mode but opt for SS rectifier since it gives a tighter sound and works better for heavy music.

:crazy

[JPW]

Yes, exactly - it's because of the current rating of rectifier tubes. A 5U4 - the type Mesa use - is limited to 275mA. (GZ34s are 250mA, 5Y3s are only 125mA for example.)

A 50W amp draws approximately 250mA at full power (bearing in mind that a typical amp is no more than 50% efficient, so the power supply needs to provide 100W, and at a voltage of 400V that would require exactly 250mA - the real figures will vary slightly depending on the voltage and the exact efficiency), so a single 5U4 or GZ34 is only enough for a 50W amp. A 100W amp needs two, and a 150W amp needs three. It doesn't matter how many power tubes are used to produce the power - a 2x6550 amp can produce 100W too, and would still need two rectifier tubes. A 4xEL84 amp only needs one because it's limited to around 45W at most.
Just curios, but could you use a 5y3 rectifier tube in a germino lead55 lovo running with 6v6's. I heard somebody talk about this before and they used it to make the amp break-up sooner I think? Just curios cause I don't know.

[kwk13]

I guess what's interesting to me (or should I say confusing then) is why they chose to call the amps "Rectifiers" when in effect (I'm assuming here) that any 100 watt, tube rectified amp would be a "dual rectifier" and any 150 watt, tube rectified amp would be a "triple rectifier". I guess the "dual" they were going for was the switching of solid state rectifier to tube- although that's lost on the "triple" becasue you are really only dual rectifying (tube or SS) three channels? I guess it's really all semantics.

Thanks for all the great info! I've just always been curious what the meaning was and I think I get it now.

[sosomething]

I guess what's interesting to me (or should I say confusing then) is why they chose to call the amps "Rectifiers" when in effect (I'm assuming here) that any 100 watt, tube rectified amp would be a "dual rectifier" and any 150 watt, tube rectified amp would be a "triple rectifier". I guess the "dual" they were going for was the switching of solid state rectifier to tube- although that's lost on the "triple" becasue you are really only dual rectifying (tube or SS) three channels? I guess it's really all semantics.

Thanks for all the great info! I've just always been curious what the meaning was and I think I get it now.

Not quite, because as John stated a SS rectifier (the kind most amps use) is perfectly capable of handling 100 watts of power and more. Marshalls, for example, use SS rectifiers - thus making them (even the 200-watt Majors) single rectified designs by any definition.

[scopeboy]

The name is just a marketing tag. If you expect it to mean something, that's like asking what kind of shells a Dodge Caliber fires. ;-)

They probably called the original Dual Rectifier by that name because, hey, it had two rectifier tubes and nobody had bothered doing that before: they just used solid-state rectifiers once they got beyond what a single 5U4 rectifier could handle. Once they had a dual rectifier, hey, why not go one better!

Designs from the "original" tube era hardly ever used multiple rectifiers to handle higher currents. Once you got above what a single 5U4 or whatever could take, it was time to go to mercury vapour rectifiers like the 866. Then silicon diodes came along and killed tube rectifiers.

[John Phillips]

Marshalls, for example, use SS rectifiers - thus making them (even the 200-watt Majors) single rectified designs by any definition.Actually the Major - certainly the very earliest ones, I think they may have changed later - does use dual solid-state bridge rectifiers in parallel, for the same reason... the diodes available back then couldn't handle enough current. If you look at the schematics, only one bridge is shown, but it's labeled 8xA10D10.

:)

[AL30]

Thanks for the info guys. Much appreciated. :AOK

AL

[sosomething]

Actually the Major - certainly the very earliest ones, I think they may have changed later - does use dual solid-state bridge rectifiers in parallel, for the same reason... the diodes available back then couldn't handle enough current. If you look at the schematics, only one bridge is shown, but it's labeled 8xA10D10.

:)

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Thanks John. :)

[VacuumVoodoo]

There's one small thing they missed in the DR design which if implemented would make a difference in sound between tube and SS rectification substantially larger.

I'll provide info on this in PM if you're interested. You must promise you won't pass it on to R.S. It's just too basic :);)

[RedMan]

I guess what's interesting to me (or should I say confusing then) is why they chose to call the amps "Rectifiers" when in effect (I'm assuming here) that any 100 watt, tube rectified amp would be a "dual rectifier" and any 150 watt, tube rectified amp would be a "triple rectifier". I guess the "dual" they were going for was the switching of solid state rectifier to tube- although that's lost on the "triple" becasue you are really only dual rectifying (tube or SS) three channels? I guess it's really all semantics.

Thanks for all the great info! I've just always been curious what the meaning was and I think I get it now.

Its not true at all that any 100 watt tube rectified amp needs 2 rectifier tubes. There are 100 watt amps that use a single rectifier tube. They will sag a bit more than using 2 rectifiers for the same power but thats not necessarily a bad thing. Mesa could have used a single tube rectifier for thier 100 watter but decided on 2 probably for a tighter sound, reliability and perhaps some marketing hype. You gotta admit it looks cool to see a row of 6 or 7 power tubes.

[daddyo]

Announcing the Fender 57 Twin Dual Rectifier!!!

[Random Hero]

Its not true at all that any 100 watt tube rectified amp needs 2 rectifier tubes. There are 100 watt amps that use a single rectifier tube. They will sag a bit more than using 2 rectifiers for the same power but thats not necessarily a bad thing. Mesa could have used a single tube rectifier for thier 100 watter but decided on 2 probably for a tighter sound, reliability and perhaps some marketing hype. You gotta admit it looks cool to see a row of 6 or 7 power tubes.

Or 9 tubes, in the Triple.

[jessekates]

Thirdly, in the Blue Angel there is one rectifier tube, and it isn't switchable (I think it might have been on the earliest models). But it's still a Dual Rectifier because it uses separate tube (for the power stage) and solid-state (for the preamp) rectifiers. The purpose of this is to guarantee that the preamp has greater headroom than the power stage, so the power stage clips first.

I owned and loved a Blue Angel for about 7 years and never understood why it was called a "dual rectifier" until now. Thanks for clearing that up!

[JJman]

Don't tube rectifiers have better tone since they are Class A ? :crazy

And wouldn't 2 tube rectifiers sound twice as good since that would be Class AA? :messedup And 3 tube rectifiers>>>:eek:

http://www.thegearpage.net/board/images/icons/icon7.gif

[r9player]

Why not check in with Greg (he posts here as well ...)

Just curios, but could you use a 5y3 rectifier tube in a germino lead55 lovo running with 6v6's. I heard somebody talk about this before and they used it to make the amp break-up sooner I think? Just curios cause I don't know.

[epluribus]

Tube vs. Solid State rectifiers...here's a link to an article on Aiken's website about Sag.

http://www.aikenamps.com/Sag.html

To a lot of guys Sag is a feel thing more than a tone thing, though I hear a pronounced difference in pick (attack) detail with the switch thrown to SS in a Dual Rectifier. (Also true of a Deluxe Reverb with tube vs. SS rectifier--the DR II is SS. See Aiken, however, on how you can get SS to sag a bit anyway.) I've always assumed sag was the main culprit in the Dual Rec, but John suggests different. Mesa DRs also have distinctly different pick dynamics, the way they go in and out of dirt when you dig in, depending on where the switch is--IME, natch.

Actually, I'd love to know more about why the two positions do indeed sound and play so differently. Great amps.

--Ray

[John Phillips]

It's not just the dynamic change of voltage (ie sag) you need to consider, its the static change too - because the amp is drawing significant current even at idle, the resistance of the rectifier tube cases a substantial drop in B+ voltage compared to the solid-state diodes, which have almost no resistance. This lowers the tube plate and screen voltages, and also - indirectly - changes the bias, because the bias supply voltage is not lowered, since it's supplied by a separate circuit. So actually, the bias voltage is proportionately higher and the amp will be biased colder in tube rectifier mode.

[VacuumVoodoo]

SS/tube rectifier switching arrangement in Fender Prosonic also adjusts bias accordingly.This is correct way of doing it from purely engineering POV.
I would question suitability of this for intended use i.e. giving the amp different response characters.
In my experience with dual rectifier arrangements I found that setting bias at nominal value in SS mode, as it gives cold, but not "class B cold", bias with tube rectifier gives best results.

[epluribus]

It's not just the dynamic change of voltage (ie sag) you need to consider, its the static change too - because the amp is drawing significant current even at idle, the resistance of the rectifier tube cases a substantial drop in B+ voltage compared to the solid-state diodes, which have almost no resistance. This lowers the tube plate and screen voltages, and also - indirectly - changes the bias, because the bias supply voltage is not lowered, since it's supplied by a separate circuit. So actually, the bias voltage is proportionately higher and the amp will be biased colder in tube rectifier mode.

How cool is that? :BEER Thanks John, this makes tons of sense, esp when you think about all the things that change in the amp when you throw the switch.

--Ray

Y'know it would be fascinating to bias two DRs, one in tube and one in SS, so they're the same--isolate the impact of the rectifier without any other changes. Sounds like the Prosonic VacuumVoodoo mentioned. VV, any chance you've got some playing time on a Prosonic? Reviews?