Wave Arts Tube Saturator 2 User manual

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Wave Arts
Tube Saturator 2
User Manual
Copyright © 2015, Wave Arts, Inc. All Rights Reserved

Table of Contents
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Table of Contents
1. Installation and Registration.............................................................. 5
2. Plug-in Control Operation ................................................................. 8
2.1 Knobs........................................................................................ 8
3. Menu Bar and Preset Manager........................................................... 9
3.1 Bypass ...................................................................................... 9
3.2 Undo......................................................................................... 9
3.3 Copy......................................................................................... 9
3.4 A/B buffers ................................................................................ 9
3.5 Preset name and arrow controls.................................................... 9
3.6 Preset menu..............................................................................10
3.7 Factory Presets..........................................................................10
3.8 User Presets..............................................................................10
3.9 Save…......................................................................................11
3.10 Import…..................................................................................11
3.11 Export…..................................................................................11
3.12 Reset… ...................................................................................11
3.13 Tools menu .............................................................................12
3.14 About…...................................................................................12
3.15 Open User Manual…..................................................................12
3.16 Check for Updates…..................................................................12
3.17 Visit Website… .........................................................................13
4. Tube Saturator 2............................................................................15
4.1 Overview ..................................................................................15
4.2 About Tube Saturation................................................................16
4.3 About the Technology.................................................................20
4.4 Tube Saturator 2 Schematics.......................................................20
4.5 Using Tube Saturator 2...............................................................22
4.6 Parameters ...............................................................................23
4.7 Presets.....................................................................................25
Support ............................................................................................27
Index ...............................................................................................29

1. Installation and Registration
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1. Installation and Registration
On Mac OS-X, Tube Saturator 2 supports AU, VST, and AAX plug-in formats,
both 32-bit and 64-bit. On Windows, Tube Saturator 2 supports VST and AAX
formats, both 32-bit and 64-bit. Installers for Mac and Win platforms are
found on the Wave Arts web site Downloads page. Download and execute the
installer for your platform. On Mac, the installer is a “.dmg” file and on Win
the installer is a “.exe” file. The installer will ask you to accept the license
terms, and will then give you the option of selecting any or all of the plug-in
formats to install, and on Windows will give you the option of installing 32-
bit, 64-bit, or both variations. The choice of 32-bit or 64-bit depends on
whether the host application is 32-bit or 64-bit, not on the operating system.
If in doubt, install both.
Tube Saturator 2 is licensed using Pace/iLok license management. You have
the option of installing the license on a particular machine, or you may install
onto an iLok2 dongle, original iLoks are not supported.
When the plug-in first runs, or during installation on Mac, it will check for a
Pace/iLok license associated with the machine, or on any iLok plugged into
the machine. If a license is not found, it will pop up the following dialog:

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Clicking the activate button will bring up a dialog asking for your Pace
redeem code. You can copy/paste it into the field and click Next. Then you
will need to login to your iLok account or create a new account. This is
because the redeem code license needs to be associated with an iLok
account. Then you have the option of moving the license to your machine or
to an iLok.
To run as a demo, select “Try”. This will ask to login to an iLok account, or to
create a new account. Once the account is identified, a 14-day trial license is
deposited. Then you have the option of moving the license to your machine
or to an iLok.
When you purchase Tube Saturator 2, you will receive an email containing
the product serial number, of the form WA-TS2-XXXXX-XXXXX. Go to our
website registration page, enter your name, the serial number, your email
address, and select Pace/iLok licensing. This will generate a Pace redeem
code and send it to your email address.
There are two ways to redeem the code and generate a license. When
opening the plug-in the dialog window shown above will appear giving you
the option to Activate the plug-in. You can paste the PACE redeem code
there, and proceed to create or login to an iLok account and then transfer the
license to an iLok or your machine. Otherwise, go to http://www.ilok.com,
create an iLok account, and download and install the iLok License Manager.
Within the manager, under the Licenses menu, select “Redeem Activation
Code” and paste your redeem code. Then transfer the license to either an
iLok dongle or your machine. The plug-in will run only if it can find a license
on an iLok or the machine.

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2. Plug-in Control Operation
2.1 Knobs
Please refer to the following guide for information about the various ways you can
use knobs:
Function Mac Windows
Increase/Decrease a parameter value (rotate
clockwise/counterclockwise) Click on the knob +
drag up/down
Click on the knob +
drag up/down
Fine adjustment — increase/decrease
Shift + click + drag
up/down
AAX: Command +
click
Right click + drag
up/down
-or-
Shift + click + drag
up/down
AAX: Ctrl + click
Reset knob to default value
Command + click
-or-
Double-click
AAX: Option + click
Control + click
-or-
Double-click
AAX: Alt + click

3. Menu Bar and Preset Manager
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3. Menu Bar and Preset Manager
Tube Saturator 2 has the following menu bar displayed at the top of the plug-in:
This section describes the operation of the menu bar, preset manager, and the
other functions available in the menus.
3.1 Bypass
Clicking on the bypass button bypasses the effect, that is, audio will pass through
the effect without alteration. The button is lit when the effect is bypassed.
3.2 Undo
Clicking the Undo button causes the parameters to revert to their settings prior to
the last edit. Only one level of undo is available, so clicking the undo button again
will restore the parameters after the edit. Both A and B buffers (described below)
have their own undo buffers.
3.3 Copy
Clicking the Copy button copies the current set of effect parameters to the unused
A/B buffer. Hence, if the A buffer is currently selected, the parameters are copied to
B, and if the B buffer is selected, the parameters are copied to A. After clicking
Copy, you can continue to make changes, and then revert to the original copied
settings by clicking either the A or B buttons to switch buffers.
3.4 A/B buffers
The A/B edit buffers allow you to compare two different sets of parameters or
presets. One of the A or B buttons is always lit; the button that is lit shows the
current buffer. Clicking either the A or B button will switch to using the other buffer,
thus changing the effect settings (assuming different settings are stored in A and
B).
Here’s how to use the A/B buffers to compare two different presets. Select a preset
from the Preset menu, then switch to the other buffer and select a different preset.
Now switch between the two buffers to alternate between the two different presets.
3.5 Preset name and arrow controls

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The currently selected preset name is displayed in the text field in the menu bar.
Changing any parameters causes an asterisk (*) to be displayed at the end of the
name. This indicates that changes have been made to the preset. In order to save
the changes to a user preset you must select the “Save…” item in the Preset menu,
described below.
The arrow controls to the left and right of the preset name cycle through the set of
factory and user presets. Clicking the right arrow goes to the next preset, clicking
the left arrow goes to the previous preset.
3.6 Preset menu
The Preset menu contains lists of factory and user presets for easy selection, and
options for managing presets. The functions are described in the following sections.
3.7 Factory Presets
Factory presets are selected from a rolloff menu at the top of the Preset menu.
Factory presets cannot be modified or deleted. The Default preset is always first in
the list; it defines all default parameter settings.
3.8 User Presets
User presets are selected from a rolloff menu just below the Factory presets in the
Preset menu. When you first run a Wave Arts plug-in, there will not be any user
presets and the menu will be empty. When you save a preset using the “Save”
option the preset is added to the User menu. All instances of a plug-in share the
same set of user presets. So, after you save a preset with one instance of a plug-in,
you can go to another instance and find that the preset can be found in its User
preset menu too.

3. Menu Bar and Preset Manager
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You can delete an individual user preset by holding down the SHIFT key while
selecting the preset. The entire set of user presets can be deleted using the Reset
option, described below.
User presets are stored in a text file called “TubeSaturator 2 Presets.txt”. On
Macintosh, the presets are stored in the folder “/Library/Application Support/Wave
Arts/TubeSaturator2”. On Windows the presets are stored in the folder
“C:\Users\<user>\AppData\Local\Wave Arts”. If the preset file is deleted it will be
created automatically by the plug-in.
3.9 Save…
When you have created an effect you want to save as a preset, select the “Save…”
option. You will be asked to name the preset and the preset will be saved in the set
of User presets. If you supply the same name as an existing user preset, the preset
will be overwritten with the new preset without any warning notice.
3.10 Import…
User presets can be written to files using the “Export” function, and read from files
using the “Import” function. Selecting the “Import…” option will first ask if you want
to replace or merge the imported presets. Replacing causes your current set of user
presets to be deleted and replaced with the presets read from the file, merging will
add the presets read from the file to your set of User presets. Then you will be
asked to choose a preset file for importing and the presets are read from the file.
Import can also be used to convert presets from an older version of the plug-in to
the current version. If the plug-in detects presets from an older version and it
knows how to convert them to the current version it will ask you if you want to
convert the older presets to the current format.
3.11 Export…
Selecting the “Export…” option will first ask if you want to replace or merge the
exported presets. Replacing causes the presets in the file to be deleted and
replaced with the exported user presets, merging will add the user presets to the
presets in the file. Then you will be asked to choose a preset file for exporting and
the presets are written to the file.
Preset Export is also useful for making backup copies of your user presets. If you
have a large set of user presets, be sure to export them to a backup file.
3.12 Reset…
Reset is used to delete all of your user presets. Selecting “Reset…” will first ask you
if you really want to do this, and if you confirm, all the user presets are deleted.

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3.13 Tools menu
The Tools menu contains various important options, described below.
3.14 About…
The About option displays important information about your plug-in. An example is
shown below:
On the top line, the plug-in name and version are displayed, along with the current
plug-in format (VST, AU, or AAX). This is useful if you aren’t sure which format of
the plug you are running. The build date of the plug-in is displayed on the next line.
The registration status is always displayed as “PACE License”. A button is provided
for opening the User Manual.
3.15 Open User Manual…
Select this option to open the user manual in a browser. If the manual isn’t found,
you will be asked to navigate to it. Once the manual is opened successfully the
plug-in remembers the location.
3.16 Check for Updates…

3. Menu Bar and Preset Manager
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If you are connected to the internet, selecting this option will launch a browser and
will navigate to the Wave Arts Downloads page.
3.17 Visit Website…
If you are connected to the internet, selecting this option will launch a browser and
will navigate to the Wave Arts home page.

4. Tube Saturator 2
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4. Tube Saturator 2
Figure 4-1. Tube Saturator 2 user interface.
4.1 Overview
The Wave Arts Tube Saturator 2 plug-in is an exact digital simulation of a dual
triode tube preamp with a three-band equalizer. Tube Saturator 2 authentically
recreates the sound of a tube amp being overdriven. It can add a touch of analog
warmth to a recording, or can be driven heavily into distortion.
Tube Saturator 2 features the following:
Dual triode preamp
12AX7 and 12AU7 tubes
Drive control for distortion adjustment
Baxandall 3-band EQ, with pre and post EQ modes
2x oversampling mode
Wet/dry mix and output gain
Bypasses for saturation and EQ
Accurate analog circuit simulation technology
Analog style metering
Tube Saturator 2's audio routing is shown below:
Figure 4-2. Tube Saturator 2 audio routing.

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The signal is first upsampled to twice the sampling rate if the 2x oversampling
option is enabled. It is then processed by the saturation and EQ modules. The EQ
processing happens first if the EQ is in “PRE” mode, if in “POST” mode the EQ is
applied after saturation. Saturation is achieved by overdriving the tube preamp.
The Drive control adjusts the amount of tube amp saturation by increasing the gain
at the input of the circuit; higher levels of input gain increase the amount of
saturation. In order to keep the overall gain roughly constant, the Drive control also
adjusts the output gain to counteract the input gain, this happens automatically.
The saturated and equalized signal is then mixed with the dry signal, optionally
downsampled, and then the output gain and metering are processed.
4.2 About Tube Saturation
Tube amps have long been revered by guitarists and other musicians as having a
fat warm sound that solid state (transistor) amps lack. This section will describe the
basics of tube amplifiers, their distortion characteristics, and why they sound better
than solid state amplifiers.
We will start with the basic building block of tube amplifiers, the triode, whose
circuit schematic element is shown below:
Figure 4-3. Basic triode circuit element.
The triode consists of a plate (also called anode), a cathode, and a control grid.
These are metal components sealed in a vacuum, usually a glass tube, and hence
the term "vacuum tube". The cathode is heated with an electric heating element not
shown in the above schematic. In operation, a high positive voltage is applied to
the plate. Negatively charged electrons escaping the heated cathode are attracted
to the positive plate, and hence electrons flow from the cathode to the plate. In
electronics the convention is to discuss the flow of positive charge, hence we say
there is a current from the plate to the cathode. The control grid is a metal screen
between the plate and cathode. Applying a negative voltage to the grid impedes the
current flow because the electrons leaving the cathode are repelled by the
negatively charged grid. By adjusting the voltage on the grid, the current flow from
plate to cathode is controlled. The triode functions much like a water valve with the
signal on the grid controlling the current flowing from the plate to the cathode (in
fact tubes are commonly called "valves").

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Figure 4-4. Simple triode amplifier. Input voltage on grid controls the current flow and hence the
output voltage.
The circuit in figure 4-4 above shows how the properties of the triode can be used
to construct a voltage amplifier. In the circuit a 300 volt power supply is connected
to the plate through a 100 kilohm resistor. Current flowing from the power supply
to the plate to the cathode causes a voltage drop across the resistor. With a 100
kilohm resistor, a 1 milliamp current causes a 100 volt drop. The graph in figure 4-
5 shows the relationship between the voltage applied to the grid and the voltage at
the output. With no voltage applied to the grid, i.e. grid at 0 volts, there is
approximately 2 milliamps of current flowing, the voltage drop across the plate
resistor is about 200 volts, and hence the output voltage is 100 volts. With the grid
at -1 volts, there is less current flowing and the output voltage rises to about 170
volts. Hence a 1 volt change in the input has resulted in a 70 volt change in the
output, so this simple circuit can amplify the input voltage by a factor of 70.
Figure 4-5. Relationship between grid voltage and output voltage in triode amp from figure 4-4.
For small swings in grid voltage around -1 volt we see that the graph is reasonably
straight, that is, the amplification is fairly linear and distortion-free, though a small

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amount of distortion is created due to the curvature of the graph. We also note that
this amplifier is "inverting", that is the output voltage rises when the input voltage
drops and vice-versa.
For large negative or positive grid voltages, the graph flattens out because the
amplifier can only produce a limited range of voltages. This means that large input
signals will result in clipped, or distorted, output signals. Clipping is also called
"saturation", which explains the name "Tube Saturator". The nature of the clipping
in a triode differs for negative and positive inputs.
For large negative grid voltages, the current flow nears "cutoff" where there is no
current flow from the plate, and the output voltage approaches the power supply
voltage, in this case 300V. This type of clipping is called "plate cutoff".
For large positive grid voltages the output voltage reaches a minimum which is
determined by the maximum current the plate can pass. However, this type of
clipping does not occur in practice because another phenomenon usually dominates
the behavior. When the grid voltage is positive with respect to the cathode,
electrons leaving the cathode are attracted to the positively charged grid rather
than repelled by it. The onset of grid current for positive grid voltages is rapid, and
the effect is to immediately decrease the input signal voltage due to current flowing
through the internal resistance of the circuit driving the grid. Hence, grid current
causes the input signal to be clipped. The mechanism of grid current clipping the
input signal determines how the amplifier will clip positive input signals.
Figure 4-6. Complete triode amplifier including cathode bias circuit and DC removal circuit.
A complete triode amplifier schematic is shown in figure 4-6. It has a few additional
details missing from the previous example. First there is a "cathode bias circuit"
whose purpose is to apply a small positive voltage to the cathode, in this case
+1.5V. This allows the grid voltage to assume positive values up to +1.5V without
causing a positive grid to cathode voltage which would cause grid current and input
clipping. Hence for small input signals oscillating say between -1 and +1 volts the

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cathode bias ensures linear distortion-free amplification. The second addition is a
"DC removal circuit" on the output which removes the large constant power supply
voltage. So, instead of the output ranging from say 0 volts to 300 volts, the output
will range from say -150 volts to +150 volts.
Figure 4-7. Left: 100 Hz input sinusoid. Right: resulting response of the complete triode amplifier for 1
volt input (blue dotted), 2 volt input (green dashed) and 4 volt input (red solid).
The response of the complete triode amplifier is shown in figure 4-7. On the left is a
single period of a 100 Hz input sinusoid with amplitude of 1 volt. On the right are
the outputs of the amplifier for different input amplitudes: 1 volt (blue dotted plot),
2 volts (green dashed plot), and 4 volts (red solid plot). One can clearly see that
the 4V input has caused an output that is clipped. However, the clipping is smooth
with rounded edges on both positive and negative waveforms. The other important
factor is that the output waveform is asymmetrical: the negative amplitudes are
greater than the positive amplitudes and the shape of the positive and negative
clipping is slightly different. The positive input causes a negative output which is
clipped due to grid current, while the negative input causes a positive output which
is clipped due to plate cutoff.
Transistor amplifiers have very different characteristics. They are very linear until
they hard clip, and the hard clipping characteristic is the same for positive and
negative inputs. Hence, transistor amplifiers will clip by producing square waves
whose positive and negative shapes are symmetrical. The symmetry is important
because it determines the harmonic content of the distortion. Symmetrical
waveforms as produced by transistor amplifiers produce odd harmonic distortion,
for example a 100 Hz tone would produce distortion harmonics at 300 Hz, 500 Hz,
700 Hz, etc. Asymmetrical waveforms as produces by tube amplifiers also produce
even harmonic distortion, for example a 100 Hz tone would produce 200 Hz, 400
Hz, 600 Hz, etc. in addition to the odd harmonic products. The even harmonics,
being octaves of the original tone, have a different (and many would say more
pleasing) timbre than the odd harmonics.

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In summary, the basic triode amplifier can produce linear distortion free
amplification for small input signals. Larger input signals cause clipping, but the
saturation characteristics are very smooth. Hence the onset of distortion is very
gradual rather than abrupt and the distortion is less harsh. There are different
mechanisms responsible for positive and negative clipping, this results in
asymmetrical distortion and the production of even harmonic distortion products
which gives a more musical tone.
4.3 About the Technology
What makes Tube Saturator 2 special is the technology used to simulate the tube
sound. On the surface, it appears similar to a myriad of other plug-ins that purport
to reproduce the sound of some analog circuit. However, under the surface, Tube
Saturator 2 uses technology that really does accurately reproduce analog circuits.
The technology, aptly called “circuit simulation,” is not new. The best known circuit
simulation program, called “SPICE,” was developed at UC Berkeley in the 1970s.
Using SPICE, an engineer can enter the schematic of a circuit and then simulate its
operation with a very high degree of accuracy. SPICE was not intended to simulate
circuits in realtime; typically SPICE users simulate circuits for brief periods of time
to verify proper operation with particular input signals. Wave Arts has developed
circuit simulation software similar to SPICE which has been optimized to run in
realtime, hence it can be used as the basis for digital audio effects. This technology
was used to implement the original Tube Saturator plug-in. However, it was still
very CPU intensive, and there was demand for the same authentic sound quality
with significantly less CPU consumption.
For Tube Saturator 2, we’ve taken another step forward. In order to greatly speed
up processing, Tube Saturator 2 uses large tables of pre-calculated data output by
our circuit simulator. Using the pre-calculated data speeds up the processing with
negligible decrease in accuracy. To ensure accuracy, we carefully compare the
output of the data-driven model with the original circuit simulation and adjust the
data sampling until the two models match with a high degree of precision.
4.4 Tube Saturator 2 Schematics
Tube Saturator 2 combines a Baxandall 3-band equalizer and a two stage triode
preamp. The circuit schematic for the equalizer is given in Figure 4-8.