A good analog saturator can really help shape the tone of a mix, bus or single instrument track. It does this by adding harmonic color and compression. Not only could this be achieved by a saturator designated for that purpose, but it’s also possible with old gear like a tape machine or vintage tube compressor.
But what if you didn’t have access to this equipment? Is it impossible to be able to obtain this sought after sound? Not at all. On this list, we will look at some of the best saturator plugins available. They are also totally free.
Tube Amp is a free plugin from Voxengo. Compared with their other tube amp sim, the Boogex, it’s a more subtle plugin that is better suited for saturation as opposed to distortion. It’s more of a microphone tube-amp preamp sim than a guitar amp sim, which makes it perfect for this list.
Here’s an explanation of the 5 knobs and their functions:
- A drive knob to control the level of saturation.
- Bias, for simulating mis-biasing at the transistor stage of an actual tube amp. You can play around with this to get different tonal qualities from your saturation.
- An LP Freq, which is the low pass filter on the software. Using this will give a sound more similar to an amp with old tubes in it.
- Dry Mix, for balancing the original audio sound with the sound that the plugin has created.
- There’s an Out Gain knob, which sets the overall level.
Some extra features to note is that it comes with an A/B button, so you can quickly switch between the sound before the plugin was used to the sound after it was used. This would help a lot when mixing to hear what effect it’s having in your mix and if it’s desirable. There’s also zero latency, making it handy for recording live performances by being able to hear how it sounds before it’s recorded.
Tube Amp can be applied to your synths, to give them a bit of tube warmth, or even on your busses or master bus, to add some mix glue whilst giving some interesting coloration with subtle or rich harmonic content. When you find some settings that you like, you can save them in the preset manager.
This plugin is a soft saturator from Klanghelm, which is a lightweight version of their paid SDRR saturator. Although using a more stripped-back control scheme than the paid counterpart, it still uses the same saturation algorithm, providing a saturation tone reminiscent of analog gear. It has six knobs (whilst the SSDR has eight), here’s what they are and the effect they have on the audio signal:
- A drive knob for dialing in the amount of saturation.
- The ASYM mix knob for changing the symmetry of the signal without affecting the harmonics too much.
- A response knob allows you to make more obvious EQ changes and to add different harmonic qualities.
- A knob for controlling the output level.
- The trim knob helps to make sure that a level of 0db is being hit on the VU meter (seen to the right of it).
- A knob called X-talk, which sets the amount of crosstalk happening in the signal.
With these simple but effective settings, both singular tracks and busses can benefit from this plugin being added to the signal chain. On busses, it would work well as a more subtle effect, especially on the master bus (acting as mix glue or to make the track pop by adding subtle coloration). For singular tracks, it could be used more aggressively to make instruments cut through the mix when EQ isn’t giving the desired effect.
Another great feature is that it comes with both a VU meter and an RMS meter. This helps to monitor the output level of the audio and keep it at the right level, so that it’s not possible to be tricked into thinking something sounds good just because it’s louder.
As this plugin has a versatile range of applications, whilst being simple to use, it’s definitely recommended.
This is a free tape emulation plugin, released by Jatin Chowhury in 2019. It’s completely open-source (along with the other plugins that Chowhury has to offer), which means that if you’re tech savvy enough, you can mod the software as you like. Originally, the Chow Tape Model was meant to emulate a Sony TC-260, but it then became capable of emulating a wide range of reel-to-reel tape machines.
There’s a whole lot of knobs and sliders to play around with here, so many kinds of sounds can be achieved by it. As the aim is to capture the sounds of a tape machine, classic analog tape saturation can be obtained by increasing the saturation knob. But it doesn’t stop there with the saturation, alongside this there’s also a Bias knob (which affects the quality of the signal, higher for higher fidelity or lower for a ‘deadzone’ distortion sound) and a drive knob (for a more classic nonlinear overdriven sound).
There are wow and flutter settings on the far right. Using this gives you the ability to be able to control whether the tape reproduction is new (with little wow and flutter) or old (with a lot of wow and flutter). These settings work really well for lofi music in general. On top of this, there are also tape compression, degradation, filter, tone and chew knobs and sliders that grant us an in depth range of a tape machine’s sonic potential.
Download: Chowdhury DSP
Here we have the Szechuan Saturator by Coda Labs. Designed in the style of McDonald’s infamous Szechuan Sauce, this saturator comes packed with some really intense saturation effects. Something unique about this plugin is that the saturation function is altered by the volume level passing through it. It comes with six knobs:
- Adjusting the Intensity knob will change the effect of the saturation from subtle to super aggressive.
- The Mix knob controls how much of the original audio signal makes it out of the other end. You can use it to blend the saturation with the original tone, to maintain some clarity.
- For a highly overdriven, more compressed sound, turn up the In Gain knob (which controls the input gain).
- The Mod Rate knob can be adjusted to set the speed of the tremolo effect that comes with the saturator.
- Mod Depth will make the tremolo sound more intense, turning it up will create a more obvious tremolo, whilst turning it down would be more subtle.
In terms of application, it can be used on a drum bus for a subtle boost, or for an absolutely chaotic sound. It could also be used on synths combined with the tremolo effect, for sounds that stick out in the mix. Additionally, the master bus could benefit from this plugin, adding some compressed loudness to the overall mix and some interesting harmonics that change with the volume.
Download: Coda Labs
Caelum Audio have released their new iteration of Tape Casette, with a better GUI and other changes that offer a more realistic representation of an analog tape’s sound. This new version also features a switch that lets you toggle the cassette one impulse response as well as a VU meter for the left and right channels. There are six knobs at the bottom of this plugin:
- Saturation, for controlling the level of saturation, of course.
- Low Pass, which is a low pass filter. You can use it to take some high end off of a track or mix.
- Noise, to control how much noise is introduced into the signal. Tape Cassette 2 now uses noise from sampled tape.
- Wow and Flutter, which give different options to replicate the sounds of older, used tapes. With this version, the engine for it has improved drastically.
- Output, which controls the overall level of the sound leaving Tape Cassette 2.
Some additional features include an auto gain switch, to set your levels automatically, as well as oversampling, which you can take advantage of if you have a more powerful machine. Not only is this a great tape analog, it’s also excellent at creating totally different soundscapes, alien to the world of tape. It can work great on individual tracks for experimentation, or on busses and on the master bus to get a classic tape effect.
Due to its versatility, great UI and updates, Tape Cassette 2 would make a perfect addition to your audio plugin library.
Download: Caelum Audio
Analog Obsession has created a whole army of free VSTs, including many types of saturation plugins. All of them have something unique to offer and are all modelled after analog circuits. One of them that stood out, though, is the PreBOX.
It comes with 11 different models that can be selected by the knob on the left. Including models of the V76. Each setting carries a different harmonic quality that could be used in a number of situations. Turning the input slightly higher and the output slightly lower, will achieve true saturation.
This plugin is especially useful on drum busses, to glue the sound together in a subtle way. Likewise, it’s also perfect on the master bus. It could even be used on singular tracks to add interesting coloration, drive a signal or for experimental purposes in general.
There are two other knobs that haven’t been mentioned yet. The first one is the HPF knob. This is a high pass filter. When left on flat, it won’t affect the signal, but turning to the other two settings will cut the low end to varying degrees. On the other hand, the LPF knob is a low pass filter that will cut the highs.
As a simple, no nonsense saturation plugin, it makes an excellent addition to your plugin library if you want to capture the saturation of analog gear.
Download: Analog Obsession
BPB Saturator by Bedroom Producers Blog
BPB Saturator was created by Bedroom Producers Blog, and intended to be a subtler, more nuanced version of their BPB Dirty Filter. Whereas the Dirty Filter excels at really aggressive and over-the-top saturation, the Saturator is perfect for softer saturation. There are six knobs with different functions:
- A high-pass knob, for cutting the low frequencies as you wish.
- A low-pass knob, which cuts the high frequencies.
- The knob called Tube introduces tube saturation into the signal chain.
- The Tape knob adds, you guessed it, tape saturation.
- An Input knob controls how much of the signal goes into the plugin.
- The Output controls the volume that is leaving the plugin.
Something really cool about this plugin is that it can blend both tube saturation and tape saturation, so it’s not necessary to have to separate plugins to achieve this effect. As it has a low-pass filter, the higher frequencies can be taken away which helps to give a saturation effect more reminiscent of an analog saturator.
According to Bedroom Producers Blog, it can be used on bass sounds, virtual instruments, drum loops and even the mix as a whole. This makes it a rather versatile plugin. Due to its minimalistic design and simple controls, it’s easy on the CPU and can be run by lower spec computers.
This plugin is really different in that it’s extremely simple. With only one slider to control it, you might be wondering how on earth it’s possible to be able to control and get a half decent sound out of it. Well, Tape makes use of different algorithms by Airwindows to achieve this. It’s also graphicless, meaning that it will look different in every DAW.
The slider that is included is called ‘Slam’. It works a little bit like an input knob, only applying and balancing different effects as the input is changed. Although there isn’t EQ, there is distortion, compression, saturation and limiting happening at varying degrees with the adjustment of the slider, so you can still get some really different sounds from it.
Saturation-wise, it’s emulating the sound of tape and does so spectacularly. It would work really nicely on the master bus, for an old analog sound or on drum busses to glue it together. Furthermore, it would also go nicely on some synths to give them a warm, vintage tone.
With a slick, simple design, Softube’s Saturation Knob achieves incredible saturation and distorted tones for use on multiple kinds of instruments. From vocals to drums and anywhere in between, this free VST has the potential for so many applications.
There’s a big knob for adjusting the amount of saturation on your instrument or bus, as well as three different types of saturation. This is where things get interesting.
The neutral setting will change the whole signal, perfect for thickening synths or making vocals creamier.
The keep high setting will keep the sound of the higher frequencies, whilst adding saturation to the low frequencies. This would fit nicely on a guitar to give a distorted low end without losing clarity or adding muddiness to the higher frequencies. It could also be used on synths for the same reason.
If the low setting is chosen, then lower frequencies will be maintained whilst the higher frequencies are distorted. This would be perfect for squashing a drum loop without losing the original sound of the bass drum and muddying up the mix, for example. Another in which it could be used would be on a bass guitar, for having clean low frequencies with added bite to the higher frequencies, helping it to stand out in a mix with a lot of low end.
The Saturation Knob is awesome on almost anything, as long as you spend some time tinkering with the balance and saturation settings.
This leveling tool looks to be influenced by other analog leveling tools such as the TLA-100 or LA-2A. This one works quite a bit differently to the others in that it’s a compressor, as opposed to something that works with gain or emulating a tube or tape. Though using the gain knob combining compression, saturation can be achieved. Here are the knobs on the leveling tool:
- A gain knob for controlling how much gain is happening, turning it up should create a pleasant analog-like saturation.
- The Peak Reduction knob controls the conventional threshold.
- Attack is to set how quickly the compressor reacts to the audio signal. Set a later response for something more similar to an analog compressor.
- Release is used to set how quickly the compressor lets go of the signal.
- Attenuation is able to be adjusted via the Ratio knob.
- The dry/ wet knob is there for balancing the original audio signal with the sound created by the plugin.
This compressor works really well on vocals, but it can also be used on other instruments. For example, on the guitar rhythm bus to glue the double tracked guitars together and provide consistency in volume. It can also be used as a peak limiter on the master bus. Additionally, the tube emulation can be noticed a lot when adding a lot of gain, as a warm, fuzzy sound is created.
Download: ADHD Audio Tools
This is a freebie based on the same algorithm as LVC Audio’s PreAMPed saturation software. It can be downloaded without any registration, too, which makes it really simple to get hold of. It’s a simplified version of PreAMPed, so there aren’t as many knobs to play around with. Even still, it can achieve a superb saturation sound.
It was intended to be used subtly, so it works really great for bringing instruments to the forefront of the mix without drastically altering the original sound. There are four different saturation modes that can drastically affect the way the plugin behaves. Each one brings its own coloration and harmonic content.
What’s more, is that it has an undo/ redo history, so you can revert to the old settings you were using, as well as 4x oversampling and the possibility of using A/B comparison. There’s also a user manual included in the download, to really help you understand how to use it from the manufacturer’s perspective.
Roth-Air by Rothmann
Ever wanted to bring out the 3k-4k region of your track to give it that classic airy sound? Well, Roth-Air can do just that! Rather than focusing on all the spectrum, this plugin focuses on that region, and it can handle that region fantastically. There are five knobs on the Roth-Air, with the following effects:
- The largest knob, ‘Air’, is perhaps the most important one. Turning it fully clockwise will give the 3k-4k frequencies a big boost, whilst turning it fully counter-clockwise will actually cut the frequencies in the area.
- There’s a Mix knob, for controlling the dry/ wet setting.
- If you would like some compression, then the threshold knob can be raised to provide the effect subtly.
- The Gain knob affects only the wet signal, so it could be used as wet-signal boost or as make-up gain reduction.
- ‘Freq’ helps to control which frequencies are boosted by Roth-Air.
This plugin would work superbly on vocals, as long as you keep something in mind. Because this plugin is targeting the area where sibilance occurs, you must make sure to run a de-esser before this Roth-Air in your audio plugin chain. If you don’t do this there could be even more harshness from this area.
It’s not just vocals that it’s useful on, though. For guitars, it can give a nice trebly saturation for guitar solos or it can be applied subtly on the drum bus, to give it some ‘air’. Another great use for it is on the actual master bus, to add some nice character to the highs of the mix.
The SGA1566 by Shattered Glass Audio is an emulation of an old school tube preamp that uses two 12AX7 amplification settings. There are some excellent features here, especially considering it’s free.
Firstly, there’s a high and low CPU switch. The low setting works well on low-end computers which is more compatible and has less latency, whilst the high setting would create an accurate representation of the tube circuit. Having both choices means that the saturation from this plugin is ready to use whether you have a simple or elegant PC.
There are two EQ knobs which can exaggerate the bass and treble frequencies. Due to the fact that the plugin uses two tube gain stages, there is a switch which lets you control whether the EQ is applied during the input or output stage. Below these, there are three knobs to control the input, output and gain of the tube saturation.
The oversampling switch can give you an even more realistic tube sound, with the cost of using up more CPU. One tip to not have to use this setting all the time is to bounce your track with this setting turned on (once you’re happy with the sound, of course) and then disable the plugin. In doing this, you will unlock the plugin's full potential without putting your computer under copious amounts of stress and crashing your system.
Another cool feature is the stereo switch, which makes it useful for both mono instruments (such as bass, vocals and guitar) and busses (like drums or panned guitars).
For synth bass and drum loops, the SGA1566 functions particularly well because of the way it adds color to an audio source. It has a lot of potential for use on guitars, bass and drums too, to add shine and depth.
Download: Shattered Glass Audio
Top Free Saturation VST Plugins, Final Thoughts
So, whether you want to use a tape saturation effect or get the sound of a worn out tube amp, there’s so many free plugins to achieve that. With all of these downloaded, you’ll be able to learn how saturation works, from different machines and use them in a great deal of different circumstances.
Apart from adding some saturation to your synth or vocals, there’s also plenty of other applications for these plugins. These include boosting the highs of the vocals, so they stand out in the mix in a pleasant way, or using it on the master bus.