Tubular Manual

Tubular is designed to be straightforward to use, with all features plainly visible and hopefully self-explanatory. This short document is intended to answer questions you might still have, and explain a little bit about what goes on under the hood.

More technical and less practical information about the inner workings of Tubular is available here.

For questions about installation, plugin formats, licensing etc. please see the FAQ.

If you have a question that is not answered on this page, please contact support@modsound.co.

Getting Started

Setting Levels

Setting levels for an amp simulator is more complicated than it should be. We've tried to make it as easy as possible: if you have a 3rd-generation Focusrite Scarlett interface, plug your guitar directly into an instrument input, and set its gain knob to minimum. Leave Tubular's Input Gain slider at 0dB. That's it!

If you have a different interface, or if there's a direct box or anything else between your guitar and the interface, it will be more complicated. Tubular applies a +9dB boost to the input signal, to compensate for the conversion factor we have measured on a Scarlett. If you know your rig's conversion factor, you can simply cancel it out with the Input Gain slider.

For example, if your interface converts a 0dBV guitar signal to a -15dB signal in the DAW, you should apply a +6dB boost, which will be added to Tubular's built-in +9dB boost.

Unfortunately, many audio interface manufacturers do not publish these conversion factors in their specifications. Hopefully, they will tell you if you ask them, but that is not guaranteed. We hope to gather more data and publish a more in-depth guide at some point.

If you don't know the conversion factor, the last resort is just to experiment with input gain settings until the amplifiers sound right to you.

Some amp simulators have an automatic level-setting function. We decided not to do this, as the voltage level coming out of the guitar can vary wildly between different pickup types. If we calibrated it to an average humbucker, it would still be quite wrong for a lower-output single coil, or a higher-output active humbucker. We have determined that it's best to let you manually set the input gain slider.

Performance Recommendations

If you're playing guitar through Tubular in real-time, you will want to minimize latency. Minimum latency is set in your DAW settings, and is affected by samplerate and buffer size. We recommend starting at 44.1kHz samplerate and 64-sample buffer size, and seeing whether you should increase or decrease the buffer size from there. The best settings will depend on your audio interface, hardware, drivers, etc. You should experiment with smaller and smaller buffer sizes until audio disruptions begin to occur.

Tubular does not itself add any latency. Make sure to avoid introducing latency with other effects or plugins - for example, limiters with lookahead.

Signal Path

Mono Input Signal  
+9dB Gain Boost 
Noise Gate 
Input Gain Slider  
Pedals left-to-right  
Amplifier Circuit Model
Amplifier 'Level' Knob 
Speaker, Cabinet, Microphone, and Room Simulation
Graphic EQ 
Split To Stereo
Post FX (Rack Effects) top-to-bottom 
Output Gain Slider  
Stereo Output Signal

Amplifier Basics

Amp Controls Gain knobs: There are typically three gain-type knobs per amp model. Usually, the leftmost two knobs will be Gain and Master, and the rightmost knob will be Level. Gain and Master are potentiometers within the simulated circuit, and both will typically affect the tone coming out of the amp. The Level knob is a pure digital volume knob that allows you to adjust the overall volume without affecting tone.

Volume compensation: The Gain and Master knobs in each amp are automatically volume-compensated to make it easy to tweak them with a relatively constant output volume, unlike real amplifiers. However, certain situations will require some additional Level-knob tweaking, particularly with clean sounds, and with especially high- or low-output pickups.

Channel knob memory: Each amplifier's channels store their knob positions when you switch to a different channel or amplifier, so that when you return, you won't have to dial them in again.

EQ knobs: As with real amplifiers, the Bass, Middle, and Treble knobs usually control potentiometers in the preamp's tone stack. These are fairly coarse EQ controls that can drastically change the sound of the amplifier. The Depth and Presence knobs are shelf-like filters implemented in the power amp's negative feedback loop, controlling very low and very high frequencies. They tend to have a greater effect at lower master volume settings, and will totally disappear if the power amp is driven very hard.

Extra Amp Controls

Amp Extra Controls The settings button on the amplifier front panel opens an overlay showing the extra amp controls. This holds any additional amp-specific knobs and switches, as well as knobs that control the power supply dynamics. All of these parameters are set per-channel, as with the front panel knobs.

Extra amp controls will show up on the left side of the screen. These are sometimes additional distortion knobs, sometimes bias switches, sometimes filter frequency shifts, etc. Select amps have switchable mods, often to boost gain.

Power supply controls are on the right side of the screen. The GRID and SCREEN fields show the two most relevant voltages in the power amp, measured at the grid and the screen of the power tubes. Both are somewhat affected by all four of the knobs.

You don't ever have to touch these controls if you don't want to. It can be difficult to predict their effects on the sound if you aren't familiar with amplifier circuitry. They are set to reasonable values automatically when you load an amp for the first time.

The Bias knob is familiar to many guitarists. It affects the input volume at the power tubes. Lower "colder" values will tend to clean up the power amp, and sometimes scoop the mids a bit. If the bias is too cold, the amp can start to "cut out," especially with lower values of the Voltage knob. Higher "warmer" bias values will let the power amp distort more easily, and tend to bring the mids forward. High values will start to sound a little "wooly" and loose.

The Voltage knob controls the input voltage to the power supply circuit. Higher settings will tend to increase both volume and headroom. At low settings, the amp will become more aggressive. This can be useful with vintage-style amps that were not designed for maximum overdrive.

The Sag knob controls the parasitic resistance of the power transformer. Higher settings will reduce the steady-state screen voltage, and will also cause additional voltage drop when a loud signal hits the power tubes. Turning the Sag knob to the right by 10-30% is equivalent to switching a diode rectifier to a tube rectifier. This will make a bigger difference on vintage-style amps that require loud volumes to get distortion.

The Ripple knob affects the amplitude of ripple at the rectifier. This has a negligible effect on most amps, which filter out this signal almost completely. Higher values can add a small amount of "ghosting" to notes on certain vintage amps with weak filtering.

Speaker Cabinet Section

Speaker Cabinet Speaker and cabinet selection: Speakers and cabinets are modeled as independent impulse responses that can be mixed and matched.

Microphone controls: The 57-421 knob blends between two microphone models that are commonly used on guitar amps. The signal coming out of this blend of microphones can then be mixed with the overall room sound with the room-mic knob. You can adjust the overall frequency response of this mix with the bright knob.

Microphone position control: You can move the microphone around relative to the speaker with this control. Moving vertically corresponds to the distance to the cabinet grille. Moving horizontally allows you to position the mic at the center cap, or farther out on the cone. The mic is always placed on the left speaker in a multi-speaker cabinet, so moving the mic to the right will mix in more sound from an adjacent speaker.

Room controls: Tubular includes an early-reflections reverb module to simulate sound bouncing around near the speaker cabinet. The reflect knob controls the volume of this module, or the "liveness" of the room. The density knob controls the number of discrete echoes - higher knob positions correspond to smaller rooms, or more objects around for sound to bounce off of. The random knob allows you to select a randomly generated room shape, much like a Minecraft world seed.


Pedals are processed left-to-right, and any pedal can be put in any slot, or even multiple slots. Many are self-explanatory, but some usage notes are below.

Wah-wah: Tubular does not directly support MIDI, but you should be able to map a MIDI controller to the Wah knob through your DAW. Consult your DAW's documentation for information about how to do this.

The Threshold knob is used to set a point in the Wah knob's rotation at which the effect is disabled. This enables you to leave the wah pedal activated all the time, and turn it off simply by setting Wah to the minimum position, like some real-life wah pedals.

Drive pedals: Tubular contains several drive-type pedals, usually with Drive, Tone, and Volume/Output knobs. It's useful to experiment with different combinations of Drive and Volume settings - many guitarists like to use a drive pedal as a near-clean boost, with the Drive set to minimum and Volume set near maximum.

Clean Boost: This flexible pedal lets you hit the amp harder, with an adjustable volume boost, as well as the Tight knob (highpass filter) and adjustable mid boost. It is a pure clean boost, with no simulated circuitry, so when the Tight, Mid Boost, and Level knobs are set to minimum, it does nothing at all to the signal. It pairs well with high-gain amps that may sound somewhat muddy without a highpass filter or mid boost.

Compressor and Simple Comp: The Simple Comp is an easy, 2-knob, aggressive compressor. It will instantly add sustain to your solos and body to clean notes. If you'd like a bit more control than that, the Compressor is a fully-featured dynamics processor with variable threshold, ratio, and attack and release times.

Phaser and flanger: These pedals create whooshing sounds. Speed and Depth control how fast it goes, and how noticeable the effect is. The flanger's Manual knob sets the midpoint of the frequency sweep. The Regen knob makes the effect more aggressive by feeding it back into itself.

Delay: This pedal is a simplified mono version of the echo419 rack module. In general, we'd recommend using the rack delay, but the pedal version can be useful for interesting feedback effects with higher gain amplifiers.

Stereo Rack Effects



Time&Space is a stereo modulation processor designed to create some stereo field motion in the narrow signal coming out of the cabinet section. As of Beta 0.9.3, its two modes are Chorus and Harmonic Tremolo.

Doubler introduces a very short time delay between the left and right channels, as well as subtle pitch and volume modulation, to create a wide stereo image from a mono signal. It creates the impression of a double-tracked guitar part.

Chorus mixes pitch-shifted copies of the input signal together. The left and right channels are processed independently, with different coefficients. This creates a widening effect, spreading the mid-focused signal out into the stereo landscape. At low depth values, this can be perceived as a subtle doubling effect, similar to recording two guitar parts.

Harmonic tremolo (often incorrectly called "harmonic vibrato") splits the signal into high-frequency and low-frequency components, then applies tremolo (volume modulation) to these signals out-of-phase, creating an interesting motion effect. Tubular's harmonic tremolo also processes the left and right channels out of phase, so in total there are 4 independent tremolo signals. Combined, they seem to move around in 3d space, somewhat like a Leslie rotating speaker.


Echo419 is a stereo delay unit with smooth modulation, filtering, ping-pong, and reversing capabilities. It has three modes. Normal mode is a straightforward digital delay, albeit with analog-like smooth modulation. Filtered FB mode applies the output filter to the feedback loop, making successive echoes darker over time. Reverse mode plays blocks of audio backward on the way into the delay unit. Short melodic phrases will come out backward, if you time them right. (Reverse delay is an interesting effect, but is impossible to get completely right, because it cannot see the future.)

If the Ping-Pong switch is engaged in any mode, echoes will alternate between the left and right channels; otherwise, they are mid-focused.


Velvetverb is a lively reverb effect, first released as an independent plugin. It was designed specifically to widen guitar signals, instantly transforming a mono signal into a wide reverb tail. Tubular's version of Velvetverb is identical sonically, but has a simplified control layout to fit into the required space.


What's in a preset: A preset stores all of Tubular's parameter values, as well as the hidden stored channel parameters of the current amp (see "Channel knob memory" above). So, if you dial in Channel 1 and Channel 2, then save a preset from Channel 2, the Channel 1 knob positions will be saved too. This only applies to the currently selected amp, and does not affect all the other amps.

User preset organization: When you save a preset, it is placed into the User Presets folder. You can organize your presets by clicking on Open Presets Folder and creating additional folders next to User Presets. This is particularly useful for importing a folder of presets made by someone else.

For example:
  User Presets/
  Super Awesome Metal Presets/
Tubular will look for preset files in every subfolder of Presets/, but only one level deep.

For information about installing Tubular, and what platforms it supports, please see the FAQ.

Tubular includes open-source software written by third parties. For more information, see the acknowledgements.


VST is a registered trademark of Steinberg Media Technologies GmbH.