UBK Novatron Varitone Tube Compressor Review


Novatron is a varitone compressor plugin released by UBK. It is priced at $149 and available as a VST, AU, and AAX plugin for PC and Mac.

The company is known for manufacturing hardware units and developing their respective software emulations, both of which are always slightly out of the ordinary. I have previously reviewed their Clariphonic DSP mkII parallel EQ plugin.

Vari What?

What exactly is a varitone compressor? When you’re browsing compressor plugins, especially those that model analog units, you will notice that the developers usually reference the type of compressor that the plugin models. Whether it is a FET, Opto, or Vari-Mu compressor, the description says a lot more about the plugin and its counterpart hardware unit than you may think.

Modern digital software compressors, such as the stock compressor you may have in your DAW, are littered with options and adjustable settings, but the same is not necessarily true of hardware units, especially the sought-after vintage types. Threshold levels, attack and release times, the way the compressor detects and reacts to the incoming signal, many of these settings were specific to specific models and contributed to the lauded character of a particular unit. For instance, the way in which a Vari-Mu compressor reacts to the incoming signal might give it a reputation for smoothness, whereas FET compressors might have a faster attack which might make it desirable in a limiting application. The specific saturation and tone of a compressor is something that’s often talked about with analog units.

The Novatron is an analog compressor emulation. The thing that makes Novatron different, as a ‘varitone’ compressor, is that it models the behavior of several different compressors and morphs between them as you adjust the settings. In practice, this means that you can dial in Novatron to get the fast attack times and the analog saturation expected from a FET compressor, or maybe go for a slower, smoother tube sound of a Vari-Mu, or perhaps settle for something in between. I can’t say that I’ve come across any similar plugin which offers this range of abilities. Novatron fits Kush’s back catalog of units that defy convention.

The Interface

The GUI is instantly recognizable as a UBK product, with their distinctive brown color choices and cream dials. At first glance, there are a few dials to take in, but the interface is symmetrical and centered around the three larger dials.

The first one is the Attack control. It allows you to sweep the attack time from 100µs to 30ms. Also labeled on the dial are the types of compression that are applied depending on the entered value. At its fastest, Novatron is modeling a FET compressor. As you turn the dial to a slower time, it begins to take on the character of a VCA compressor, before moving into Vari Mu territory at its slowest. At its most aggressive, the compression results in audible analog-style distortion. With the compression amount cranked to the max, you can sweep the attack dial and easily hear the different compression flavors and how they morph together.

Located in the middle is the Compression dial which provides control over the compression threshold. The dial is also linked to the internal auto-gain algorithm. The threshold value in dB isn’t shown anywhere on the interface. Novatron, like many other of Kush’s products, relies on being set by ear.

On the right is the Release dial. Just like the Attack dial, it blends the character of a FET, through VCA, to Vari-Mu, ranging between 15ms and 1.25s. Sweeping this control is another opportunity to hear the different characteristics of the individual compressor types at work.

The apparent advantage of this setup is that, with some experimentation, it’s possible to apply a setting that uses the attack characteristics of one type of compressor, mixed with the release characteristics of another. It goes without saying that this is not possible with a hardware unit or a software emulation of a specific type of compressor.

On the top left of the GUI is a volume level control, which allows you to match the volume of the compressed signal with the clean signal for a proper comparison when using the bypass control. Positioned on the top-right is a blend control, allowing you to blend the compressed signal with the original at a ratio of your taste. Additionally, there is a sidechain high-pass filter. The filter allows you to alter the frequencies that the compressor’s internal detector is listening to. By setting the sidechain HPF value anywhere between 0Hz and 3kHz, you can make the compressor ignore the low-end frequency content that would otherwise trigger compression. I found this very useful on drum room mics where I didn’t want the kick drum to interfere with the gain reduction on the cymbals.

In the center-middle of the GUI is a saturation control that can be applied separately or in linked mode, affecting the input and the output saturation. Novatron’s saturation is excellent for adding a bit of grit to the compressed signal, although I seldom wanted to take either of the dials higher than halfway.

Scratching The Surface

Up to this point, I would have already dealt with more settings and parameters than most compressors allow for. However, Novatron has a few more tricks up its sleeve.

The ‘Mode’ control allows you to select between three compression modes: Mix, Punish and Limit. Switching between these modes alters both the compression ratio and the knee characteristics of the compressor. These have been dialed in by UBK and have specific descriptions in the manual. To broadly cover them, Mix is a lower-ratio compressor with a soft knee, Limit is a 6:1 ratio medium knee compressor, and Punish is a high-ratio compressor built to smash your audio, with parallel compression in mind.

Tone Shift is another mode dial which provides access to Airy, Dark, and Flat tone modes. These appear to function as a tilt EQ, giving a more proportional top end and less low end in the Airy mode, while reversing these settings in Dark mode.

Alongside all these controls is an Energy Delta display, positioned next to a Comp Activity display. Energy Delta has two dials, showing the input and output activity. It is quite a nice feature, as you can visualize the changes to the audio as you apply them, and level-match very quickly. Comp Activity shows the amount of the applied gain reduction. Also featured in the plugin is a bypass control, along with a phase invert switch, a sidechain selector, and an oversampling control.

Putting Novatron To Good Use

Novatron is loaded with a decent amount of presets. Although some are obviously included to show the amount of distortion achievable by using a super-fast attack time and the two saturators, the vast majority are more moderate entirely useable in a mixing scenario. I quite like that UBK have labeled many of the presets after various sought-after hardware units, as it makes searching for the right preset more intuitive. If you are learning about the different types of compressors and their uses, this is a really good way to get your head around the difference between, say, an SSL and a Fairchild.

Using Novatron is almost like a lesson in compressor types. Even if you don’t know what kind of compressor is right for the job, you can quickly crank the compression amount and sweep the dials until you find something that works, without necessarily having to know the ins and outs of every great compressor released over the last century. A nice touch was a section in the manual dedicated to how to properly gain stage and explore the settings of the plugin.

The question with many compressor plugins is usually, will it color my sound, or not. With Novatron, it’s not whether the compressor will color the sound but what color are you going to choose. Varitone is a very apt title for this compressor, and the plugin lives up to its own hype in this area. Transparency is not what this plugin is made for.

The Verdict

I have to say, using Novatron is a welcome break from the norm. It is a toolbox of different compressor types, filled to the top with flavor and character. Although there’s nothing wrong with having, for instance, a go-to compressor for kick drums, it sometimes means that experimentation is sacrificed for familiarity. Novatron is exceptional for the sheer amount of different sounds and feels you can get out of it, and of course, because of its architecture, some of those sounds are only currently possible in the software realm.

Novatron is an excellent piece of software It is a lot of fun to use, and sounds amazing. UBK certainly do things their own way, and the results speak for themselves.

More info: Novatron (149)

UBK Novatron Review


With Novatron, it’s not whether the compressor will color the sound but what color are you going to choose.

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About Author

Johnny Marsh is guitarist and drummer from Stourbridge, England. He produces electronic-infused progressive metal under the moniker T3TRA, with a particular penchant for blending downtuned guitars with synthesizers. He also drinks far too much coffee.

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