Amp sims Best of 2020 Nembrini Audio Reviews

Nembrini Audio Cali Dual

A very well developed plugin based on one of the most iconic American amps ever made; The Mesa Boogie Dual Rectifier!

Rating: 9 / 10

Rating: 9 out of 10.


Ahhh yes, the Mesa Boogie Dual Rectifier, the diamond-plated God that started my obsession with guitar amps. In the mid 90s, I was a metal kid that had been adopted by the skate punk scene and specifically in 1997, I was introduced to the amp as the “Rectum-frier” by at-the-time NUFAN lead guitarist Chris Shiflett (now of Foo Fighters) after a bar show when I had the balls to ask him what amp he used. From there I began to notice just how many of the bands I loved were using the amp or one of it’s Mark series older brothers. Since then, I have come across the amp in the backlines of countless incredible artists across a ton of genres. The names on that list would likely drop more than a few jaws, that’s for sure.

It’s three channels and 100 watts of pure 6L6-fueled, American-made muscle designed to be basically a tone bulldozer. The Dual Rec is not just meant for a wall of high gain but a wall of just about any style of gain. There are many reasons the amp has been a literally ageless legend from the second it was released to the moment of this review. As a result of the amp’s immense popularity in the analog world, many developers have taken a swing at the modern behemoth but the many swings have not really turned up a lot of homeruns if you catch my drift. At most, maybe a triple and a few RBIs but, nothing over the fence.

Nembrini Audio hits the market with the Cali Dual to compliment the Cali Reverb plugin (Recto-Verb) the company has already released. The Cali Dual is delivered in a suite style plugin with a cabinet section, IR loader and some signal processing tools for a price that runs along with the rest of the upper-tier plugin market.


Nembrini Audio’s plugin always look great and this is no exception. The GUI looks awesome overall but I question why the plugin doesn’t sport the actual diamond plate pattern on the front. To go to the levels the developer has gone to in order to provide a lot of authenticity, why not go the extra mile? The metal in place makes the amp look a little more like a Peavey XXX or something like that. No slight on the score here, just a personal preference. Everything is laid out very efficiently here, there’s always attention put towards ease-of-use. We would generally suggest this plugin for intermediate users and up with analog knowledge of the Rectifier being very handy.

There’s a percentage of amp sim users that want and expect perfect tone right out of the box and with some products, that’s possible but the Mesa Boogie Dual Rectifier is by all means not quick to dial in. Nembrini Audio has ensured the Cali Dual plugin holds up the authenticity side of things and with that comes all of the analog amp’s quirks. Having experience dialing in a real Dual Rec will absolutely help in the pursuit of tone with the Cali Dual but if that’s not an option, spend time reading about the amp, it’s settings, controls, switches, channels and everything else under the hood so that users can really nail the tones they are after. Key switches like the “raw/vintage/modern”, the variac “bold/spongy” and diode/tube must be explored to showcase the amp’s full capabilities.

A big part of dialing in any Mesa Boogie Dual Rectifier or any plugin based on one is learning how to control the low end without a tube screamer or boost assistance. Many players will throw a screamer/boost out front without thinking and it is definitely a good move but not just yet. The amp is so low end heavy that the low end controls often need to be dialed way back to anywhere from shut right off to around 3-4 max. Yes, it’s that bassy. Learning how to shape the tone with the amps controls before adding a screamer will turn up much better results than simply parking one out front to start the process. With a boost, the low end controls can then come up pinch by pinch until it’s adding just the right amount of punch.

Channel 1 can be clean or dirty depending on the switch labeled “clean or pushed”. The clean channel doesn’t really yield tones that I would use in a tracking setting given the extraordinary clean tones available around the market but it does sound pretty good if dialed in right. To be fair, the Dual Rectifier isn’t really known for it’s ability to produce angelic or shimmery cleans so let’s take that with a grain of salt. The tones are for the most part warm, fairly bright and with some outside delay or reverb, the tones can be more than passable. I had a lot of fun laying into the cleaner side of the plugin with a Telecaster and a compressor out front in the signal chain. With the plugins 212 cab options or perhaps 212 options from user collections bring out a nicer and less beefy side to the sound here but ultimately, the cleans are just not the focus of the amp.

My preferred side of the Cali Dual’s first channel is when the switch goes to the “pushed” side. This switch unlocks some of my all-time favorite Rectifier sounds. Raw, rock, medium-gain with punch and attitude that I love using for various types of punk rock, rock, black metal and a lot more. Rhythm or lead, channel one gets the job done nicely. I don’t usually prefer Dual Rectifiers for lead/solo applications but the pushed switch turns up some really soulful lead tones that lean towards blues rock, fusion, classic rock and other similar applications. Toss in some delay and you may just fall in love.

Channel 2 opens up another element to the amp with the “Raw/Vintage/Modern” switch. As mentioned above, understanding the controls is key and this is one of the most crucial to the tone. The short version of what this switch does is the three modes alter the power amp response to negative feedback and thus the amount of distortion it is capable of producing. Modern delivers the most and raw, the least. This switch has been modeled pretty nicely in all three positions. I have always been a fan of simply setting the switch to modern and then going about the rest of my business with the amp but again, this is merely a preference.

CH2 is probably the most well-rounded of the amp’s trifecta of terrific channels in that it’s the most versatile. With time and tweaking, Channel Two can do a whole lot really well from death metal to classic rock and most of the ground on the way between. There’s enough gain in the channel to get really heavy or dial it back a bit for a full dose of rock. Where CH1 can be a bit lighter and CH3 is geared a little more towards high gain applications, CH2 is more of a Swiss Army knife. When I need CH2 to do a little more, a boost pedal plugin goes a long way. Don’t be afraid to dial in a bit of the pedal’s drive to add some extra saturation to things. This channel also seem to play best with literally every IR I used, both internal and third-party with 412 and 212 closed back being my favorite starting points.

Ah yes, the famed “dead red” legend; CH3! This channel is one of the amp world’s most valuable players. After all, the Rectifier’s third channel has been the sound behind some of the heaviest guitar tones imaginable. There’s a good chance that well over half of the artists known for using the amp probably leaned on this part of the American-engineered masterpiece 100% of the time. Nembrini Audio’s attention to detail allows users to tap into some of the heaviest tones the analog amp is capable of but like the real deal, dialing in the perfect heavy tone can take some time. Keep in mind, just this one section of the amp is known well for crushing tones well showcased by Korn to Cannibal Corpse to Hatebreed and very notably; Rammstein to name only a few. Even just in that small sample size of the signature sounds that have made the analog inspiration for the Cali Dual the ageless wonder it is, that’s a wide array of tones. With such an array of tones available in one amp, there’s usually going to be some control surfing to do.

With the release of the Cali Reverb, Nembrini Audio began to employ a more streamlined cabinet section which also spawned V2 versions of a couple Nembrini classics. I found the tones best with the cabinet section’s “ambient” mic all the way down or muted from the very beginning. The ambient mic adds really nothing to the big picture with the Dual Rectifier for my personal preferences. It just adds mud and takes the tightness away from the low end of an amp that already has a ton of it. I would really only suggest the ambient mic for adding a little more depth to leads and solos but even then, for that application I will only blend it in on the mixer about 5% or so. With other amps, it’s a bit more useful but it doesn’t add a lot in this instance.

The selections available in the cabinet section offer up a lot of different ways to voice the classic Rectifier sound. Bogner, Fender, Marshall, Mesa Boogie, Peavey, Orange and more names are available with a nice selection of mics and controls for distance / position to shape the sounds further. I really enjoy mixing two 57s with one further away and positioned to provide a bit more low end. Then in the handy mixer, I will blend the two about 70/30 or so with the closer 57 having the advantage. Blending a 57 with a 421 or 121 are also pretty much “can’t miss” ways of getting really nice tones. The ability to blend two mics on any of the cabinets is really nice and the controls / mixer provide worlds of tonal options.

I usually use a 421 mic to add a bit of low end but the Cali Dual needs absolutely no help with low end so the 421 will be moved a little closer to the center of the speaker than I would normally put it. The Marshall and Mesa cabs were my favorites of the bunch but on the other side, I really didn’t find any use at all for the Fender 410. I was a little sad to see the Soldano didn’t make the cut but perhaps for an update later on it will be considered as it’s one of the better cabinets Nembrini has offered in their past cab sections.

Users can also either bypass the cab section or use it to add up to three of their own IRs. This is the only time I’d say the GUI is a bit clunky as I really prefer to have a more flexible way to navigate through my IR collection. The Nembrini loader sort of just lets users load a file but not really being able to scroll around the current folder or elsewhere quickly and efficiently. Testing 3rd party IRs with a plugin can involve a lot of trial and error so having a quick and easy way to do that internally is needed. In this case I preferred to use my own IR loader for the selection of 3rd party stuff but on the bright side, the Cali Dual plays very well with a huge wealth of IRs from many developers. Experimentation is key!!


To continue the baseball references from the intro, the Nembrini Audio Cali Dual hits the first homerun in the long line of plugins that have been inspired by the Mesa Boogie Dual Rectifier. It’s actually the first Dual Rec plugin I have enjoyed purely with no issues since the LePou Lecto from so many years ago. This plugin provides just the right mix of authenticity and convenience. It’s warm, crisp and does a great job of recreating the best in true Recto tones.

Ideally, if I could change anything about this plugin, the only things I would do would be to ensure the ambient mic is not involved in the plugin’s default tone and add a simple boost section in with the gate and cleaner components. Otherwise, I cannot find anything to dislike about it at all. The only real downside is the high end not having a lot of headroom. The analog Rectifiers have a lot of high end to work with and the plugin just doesn’t have the same amount available. It’s not a glaring amount but I did notice that I needed to push the high end controls a little further than I normally would.

It’s been a long time coming for fans of the Dual Rectifier but the time is finally here! Buy this plugin with confidence that at least a good majority of the Recto tones you seek are waiting but only if users have an understanding of how the amp dials in and that the tone pursuit may not be instant. Understand that and there’s not much that can’t be done with this plugin for the needs of many different players.

Get it here:

Nembrini Cali Dual

See more – Nembrini Audio launch video

Demo by Choptones:

Leon Todd demo of the BST100

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