Editorial: Dual Rectifier Revisions and Versions

Posted: September 16, 2015 in Cork Sniffer Heresy, Mesa Boogie Dual Rectifier, Vanity and other sins
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Mission Improbable

There are a few reasons I’ve been spending so much time exploring the Dual Rectifier.  Those reasons include: misinformation, biases and myths, and helping others.

The misinformation takes many forms.  Sometimes, it’s just reading about the DR having “active EQ” (false), that it isn’t a “solo” amp (false), or other equally dubious claims about the design that are ridiculous.  Biases and myths also fit in with the misinformation, but are just as much about the insecurities of the users as any misunderstanding of the amplifier.  Claims about early revisions being “superior” or the utility of the 2001 3 Channel version are as ridiculous as the circuit misinformation, because it’s all subjective.  If I was a little more cynical, I’d even think the second hand market is involved in promoting and spreading this kind of bias to increase, and retain the increases on, the obsolete designs.  Seeing as how Mesa designs them, builds them, markets them, receives feedback, and profits most from the sales, if the old amps were superior, they’d swap directly back to it due to customer demands and complaints.

As a matter of fact, they didn’t go back.  My amp is now obsolete.  They made some voicing and circuit changes to the 3 Channel, which seems to marry the most positive aspects of the various revisions throughout its history and added the Clean from the Lonestar and Roadster.  I would love to see a schematic to see what all the changes are.  While I feel that an old design is worthy of being dissected and shared, the new ones should be protected for the short term, for the benefit of Mesa, but I still anticipate at least being able to compare them for myself one day, if not to eventually help people with re-voicing the older amps.

Apples and Watermelons

The early-2 Channel versions basically had only two completely usable modes: Vintage and Modern.  I can’t find samples of Blues being used much and the Clean lacked a really “clean” tone until about Rev. F.  Using the Clean also meant not using one of the dirty modes.

The 2001 3 Channels have 6 modes that all work well in the correct context.  This isn’t to say the amp is perfect.  The stock FX Loop is not great, in my opinion, and the distortion at high Gain settings can be unwieldy and unfocused.  The 3rd Channel is optimized for Modern and it shows when the other modes are selected.  The Presence frequency knee is set higher and the master volume cuts lows.  It is quite a brilliant sound compared to Channel 2.

Despite the flaws, making direct EQ setting comparisons between the early-2 Channel and 3 Channel, or, trying to translate a setting on one of them to the other, is just the wrong way to go about using one or comparing both.  A better way would be to dial in sounds that make each sound really good and compare that.  Even comparing a Rev. C to a Rev. G should be done this way.

Then there’s the notion of magical parts that give the first 3 revisions a “mojo”.  That is utter bullshit.  As much as I like Dirt from Alice In Chains and love the low Recto parts on it, Jerry Cantrell never took a Rev. C on the road.  He used Bogner and modded Marshalls for his live sound.  The bands that really embraced the Recto, like Candle Box, Soundgarden, Metallica, Korn, Limp Buttsex, Kid Rock, and the Nu-Metal guys used Rev. F, Rev. G, or 3 Channels.  Those are the tones that most people associate with the amp.  To say that 500 or so amplifiers are supreme to the tens of thousands of other amplifiers and The Recto™ sound as heard on most albums or at most live shows doesn’t make any bit of sense.

The Hills Have Ears…. For The Sound Of Music

Which brings me around to the other major bit of misinformation: Dual Rectifiers can only get one sound and that sound is extremely scooped, distorted, and harsh.  I spend a lot of time proving this one wrong.  In fact, if you look through my site, I’m constantly sharing information and settings to get a wide variety of tones.  It isn’t hard to dial in a variety of sounds if a person knows what the controls are doing.  You’d think haters would realize that the EQ, power switches, and voicing switches actually work.  In any case, the Modern mode of Channel 3 has a boosted midrange by comparison to the rest of the amp, or compared to Marshall, Soldano, Bogner, etc.  It is very far from scooped.  People can make opinionated statements all day, but the truth is right in the schematic and can be easily shown.

Positive Charge

I hope that didn’t come across as too negative, because it was more about being matter-of-fact than angry.  The result of my feelings are a positive one.  I want to help people use their 2001-style, 3 Channel Dual Rectifiers in a variety of ways.  All of the Rectos can be finicky, especially for people coming over from amps that aren’t like it.  The focus of the frequency response goes from below 100 Hz to about 2 kHz and the 6L6GC tubes reinforce this range, particularly in the bottom end.  The amp gets deep and wide, but cuts off the treble harmonics in the preamp and the P.I..  Older, pre-“modern high gain”, designs and amps built around different power tubes don’t cut the highs as dramatically to kill the squealing upper harmonics.  That can take some time to get used to.

The aggressive or incredibly distorted tones don’t need a lot of explaining.  Those are this amp’s bread and butter.  However, a variety of other tones are there to be found.  Rather than talk about subjective measurements, I’m providing analyses for the modes and for the amp in general by looking at the circuit.  People can make up their own minds about the sound and tweak things to their preference, rather than trying to fit into the preferences of a small, but vocal minority.  Even my own voice is one opinion and shouldn’t be considered the be-all-end-all of any discussion.

Gimme Some Truth

The other useful help I want to provide is modifications for users who want to get something different or to personalize their amp to their playing style.  Overall, a Rev. G. and a 3 Channel have nearly identical preamps for dirty sounds.  The settings or mods I provide will get someone with either amp in the same ballpark for those tone settings.

To reiterate a previous article, just because a mod can be done, doesn’t mean it absolutely should be done.  Before working on something that is expensive and complicated, make sure you’ve tried to dial in the sound you want or that the mod is exactly what you need.  It could be that the amp is truly not what you need.  Get the one that fills that need.  As an analogy, don’t use a nail gun on something that requires a tack hammer.

Just be true to yourself.  No matter which version a person owns, each version has its merits and demerits, the same as any other amp, and can provide a wonderful satisfaction to the user if their goals intersect with the strength of their tools.  Thanks.

  1. Saul Segura says:

    very nice article, great read!


  2. Cynical says:

    “Seeing as how Mesa designs them, builds them, markets them, receives feedback, and profits most from the sales, if the old amps were superior, they’d swap directly back to it due to customer demands and complaints.”

    That only holds true if the changes weren’t done to make the amp cheaper, which was clearly the driving force behind the Rev F (and its awesome Schumacher transformer) to Rev G (with its cheapo tranny) changes. There is a very good reason the early ones are sought after; Rev F and earlier simply sound much better than Rev G and newer.


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