The ‘tube sound’ is hard to pin down, meaning different things to different people. In reality, there are many different types of tube, and many different ways to design a circuit around them.
Tube microphones are perennially popular, but tubes are used in this context due to their high impedance, which allows for a simpler, ‘purer’ circuit design. The tube will usually operate comfortably within its most linear range, and tube mics tend to sound clean, with glossy high frequencies.
By contrast, tube mic preamps are often associated with a warmer, thicker tone than their solid-state counterparts. Driving a valve preamp hard can add rich-sounding harmonics that make the signal warmer without becoming dull.
Tube guitar amps vary a lot, from bluesy triode designs to high-gain, hard-rockin’ heavy metal pentode designs, and anywhere in between.
Finally there’s the starved plate design, known as a ‘marketing valve’, run at a much lower voltage. Here, the tube is a substitute for the transistors or diodes in a guitar distortion pedal, and isn’t much like a classic tube circuit – but that doesn’t mean it can’t sound good.
All of these tube types have been emulated in software, and here you'll find a dozen of our favourite tube emulation plugins.
12 great tube plugins
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1. Kuassa PreMix CM
Mac/PC | VST/AU | Free
This one comes free with Computer Music magazine, and provides crunchy, tube-style distortion, plus a three-band EQ with low, mid and high bands, and a clear, easy-to-use interface. Useful for gentle colouring or more obvious distortion, depending how hard you push the Gain control.
2. Audiffex STA Enhancer CM
Mac/PC | VST/AU | Free
Another one that comes with Computer Music, Enhancer CM offers five different tube styles with quite different characters, and useful sweetening Low and High Process controls. Great for adding a glossy shine to a part, imbuing a kind of rich brightness that EQ can’t manage.
3. Voxengo Tube Amp
Mac/PC | VST/AU/AAX | Free
No frivolous glowing tube graphics here, just tasty tube-style saturation with a Bias knob that changes the shape of the saturation, and up to 8x oversampling – enough to ensure that aliasing is never an issue. Voxengo plugins are solid and reliable; well worth grabbing for free.
4. Wavearts Tube Saturator Vintage
Mac/PC | VST/AU/AAX | Free
The original version of this plugin, now available free of charge, emulates a dual triode tube preamp in meticulous circuit-modelled detail. If you want the same sound without the hefty CPU hit, you’ll need to buy their Tube Saturator 2, which has been heavily optimised.
5. Shattered Glass Audio SGA1566
Mac/PC | VST/AU | Free
Another modelled tube preamp, complete with two-band Baxandall-style sweetening EQ, positionable before or after the saturation. The detailed modelling sounds glorious, but there is quite a hefty CPU hit, especially in High CPU mode with 4x oversampling.
6. Klanghelm SDRR2
Mac/PC | VST/AU/AAX | €23
Great for subtle valve-style colour, from warm and fat to glossy and shiny. The key is to tweak the Character knob (which goes from Warm to Sizzle) and the Frequency Response. This plugin includes three other useful saturation modes, making it quite a bargain at the price.
7. Soundtoys Radiator
Mac/PC | VST/AU/AAX | $129
A dual-drive tube input channel and EQ based on a tube mixer from the 1960s. You get a choice of mic or line inputs, optional added noise, and classic warm, vintage-style saturation. Their smaller Little Radiator plugin is simpler, but also sounds great.
8. FabFilter Saturn
Mac/PC | VST/AU/AAX | £114
A one-stop shop for all manner of saturation or distortion types, Saturn includes three different Tube modes: Clean Tube sounds bright and glossy; Warm Tube adds a load of even harmonics for a lovely thickening effect; and Broken Tube is filthy and full of character.
9. d16 Redoptor2
Mac/PC | VST/AU/AAX | €59
This tube preamp enables control over dynamics as well as saturation, a range of tone-shaping options, plus a powerful parametric EQ section and a limiter for good measure. A range of different colours can be dialled in, and there’s a useful mix knob to blend the results in parallel.
10. T-RackS Saturator X
Mac/PC | VST/AU/AAX | €79.99
A versatile plugin with a clear, easy-to-use interface. Choose the type of saturation you want, and how of it to apply – it’s as simple as that. You get a choice of class A or push-pull tube styles, along with a range of solid-state and tape-style non linearities, too.
11. Slate Digital Virtual Tubes
Mac/PC | VST/AU/AAX | $149
Three plugins presented as 500 series-style modules to load into Slate’s Virtual Mix Rack system. The London, NY, and Hollywood modules all model different classic tube circuits, and can be subtle or obvious in effect, depending how hard they’re driven.
12. Black Box Analog Design HG-2
Mac/PC | VST/AU/AAX | $249
Modelled after a beast of a hardware unit of the same name, this plugin provides modelled transformers, both Triode and Pentode tube stages, plus extra saturation with three flavours, and a useful Air control. It can be subtle – if you dial back the mix knob – or pronounced.
