T L Audio FATMAN FAT 1 User manual

FATMAN
by TL Audio
User Manual
FAT 1 STEREO VALVE COMPRESSOR
TL Audio Limited,
Sonic Touch,
Iceni Court,
Icknield Way,
Letchworth, SG6 1TN,
England.
Tel: [phone], Fax: [phone]
E-Mail: [email protected]
www.tlaudio.co.uk
interstage
Phistersvej 31, 2900 Hellerup, Danmark
Telefon [phone], fax [phone]
www.interstage.dk
-pro audio with a smile

CONTENTS
1 INTRODUCTION
2 PRECAUTIONS
3 INSTALLATION
3.1 A.C. Mains Supply
3.2 Line Inputs
3.3 Instrument Inputs
3.4 Outputs
3.5 Operating Level
3.6 Ventilation
4 OPERATION
4.1 What is Compression?
4.2 Why Valve Compression?
4.3 Overview of Compressor Operation
4.4 Input Gain
4.5 Output Gain
4.6 Gain Make Up
4.7 Program Control
4.8 Threshold
4.9 Ratio
4.10 Attack and Release
4.11 Knee
4.12 Meter
4.13 Compressor On
5 GETTING STARTED
5.1 Connection
5.2 In Use
5.3 Frequently Asked Questions (FAQ)
6 SERVICE
7 SPECIFICATIONS

1INTRODUCTION
Congratulations on purchasing the Fatman FAT 1 stereo valve compressor by TL Audio!
The FAT 1 is the first valve compressor to combine fully adjustable controls with fifteen
preset compression programs, allowing you the choice of creating your own unique settings
or opting for our wide selection of factory programmed presets. Now at last you have
access to professional sounding high quality valve compression for both tracking and mixing.
The FAT 1 combines classic valve techniques with solid state circuitry (known as a “hybrid”
design) in order to achieve the best combination of noise performance and valve warmth.
This makes the FAT 1 ideal for integration into both analogue and digital recording systems,
where extra warmth is required without the penalty of increased noise levels.
The block diagram of the FAT 1 is shown in Figure 1. A solid state, electronically balanced
input amplifier is used to achieve state of the art performance with very low noise, low
distortion and wide bandwidth. An ECC83/12AX7A triode valve stage (run from a
stabilised 100v DC supply) is used as a second stage voltage amplifier, to obtain the classic
valve sound and gradual overdrive characteristics. Like all other TL Audio compressors, the
gain control element of the FAT 1 is based around a special transconductance amplifier,
which avoids the use of VCAs and helps contribute to the smooth, open sound of the unit. A
certain degree of program dependant response is built into the FAT 1, particularly for the
attack and release times, and both soft and hard knee responses are obtainable.
The FAT 1 is a stereo compressor, with a single set of controls to control both left and right
channels. The unit works in linked stereo mode at all times, whereby the control voltages of
left and right channels are linked to ensure that the same amount of gain reduction is applied
to both channels (even if one signal is below the threshold). This ensures that the stereo
image is preserved. However, the FAT 1 may be used in mono by employing the left channel
only, although the processed signal will appear on both outputs simultaneously. A single
illuminated VU meter monitors the output level or gain reduction for both channels.
Line inputs and outputs are provided on each channel, on electronically balanced jack
connectors. These are fully compatible with unbalanced signals, and the operating level of the
ins/outs can be shifted from -10dB to +4dB via a rear panel switch. A pair of front panel
instrument inputs are also provided, thus allowing guitars, basses and keyboards to feed
directly into the FAT 1, removing the need for a separate DI box.
Please read this manual fully before installing or operating the FAT 1.

2PRECAUTIONS
The FAT 1 Stereo Compressor requires very little installation, but like all electrical
equipment, care must be taken to ensure reliable, safe operation. The following points should
always be observed:
-All mains wiring should be installed and checked by a qualified
electrician,
-Ensure the correct operating voltage is indicated on the rear panel
before connecting to the mains supply,
-Never operate the unit with any cover removed,
-Do not expose to rain or moisture, as this may present an electric
shock hazard,
-Replace the fuse with the correct type and rating only.
Warning: This equipment must be earthed.
3INSTALLATION
3.1 AC Mains Supply.
The compressor is fitted with an internationally approved 3 pin IEC connector. A mating
socket with power cord and mains plug is supplied. All mains wiring should be performed by
a qualified electrician with all power switched off, and the earth connection must be used.
The unit is specified for operation on nominal 230V a.c. mains only. If the power cable or
mains plug supplied with the unit is not suitable for use in your country, refer to your dealer
for a replacement.
Warning: attempted operation on the wrong voltage setting, or with an
incorrect fuse, will invalidate the warranty.

3.2 Line Inputs.
Each channel has a 3 pin TRS jack socket on the rear panel, which will accept balanced or
unbalanced line inputs providing the mating plug is suitably wired:
Balanced inputs:
-Screen = Ground,
-Tip = Signal Phase (“+” or “hot”),
-Ring = Signal Non-Phase (“-” or “cold”).
Unbalanced inputs:
-Screen = Ground,
-Tip = Signal Phase (“+” or “hot”),
-Ring = Ground.
Good quality screened cable should be used, particularly for microphone or low level
sources, to prevent hum or noise pickup. Refer to Figure 3 for rear panel connector
identification.
3.3 Instrument Inputs.
Each channel has a 0.25” jack socket on the front panel (see Figure 2). A 2 pin (mono) jack
plug is required, which should be wired as follows:
-Tip = Signal Phase (“+” or “hot”),
-Screen = Ground.
3.4 Outputs.
The outputs via 3 pin TRS jack sockets on the rear panel, and may be configured for
balanced or unbalanced connection. Balanced operation is always preferable to maintain
maximum headroom and signal to noise ratio, but can only be used if the following equipment
is also capable of balanced operation:
Balanced outputs:
-Screen = Ground,

-Tip = Signal Phase (“+” or “hot”),
-Ring = Signal Non-Phase (“-” or “cold”).
Unbalanced outputs:
-Screen = Ground,
-Tip = Signal Phase (“+” or “hot”),
-Ring = Ground.
3.5 Nominal Operating Level.
A switch on the rear panel allows the line inputs and outputs to be matched to equipment at
a nominal operating level of +4dBu or -10dBu. Most professional equipment requires
+4dBu (approximately 1.2V rms), but some small mixing consoles, portable tape
recorders or domestic audio equipment require -10dBu (approximately 225mV rms). If
the operating level is not known, the switch should be set to the position which results in the
best signal to noise ratio, whilst preserving sufficient headroom.
3.6 Ventilation.
The FAT 1 generates a small amount of heat internally, mainly due to the valve heater. This
heat should be allowed to dissipate by convection through the top grill, which must not be
obstructed. Do not locate the compressor where it will be subject to external heating, for
example, in the hot air flow from a power amplifier or on a radiator.
The FAT 1 may be free standing (using the self-adhesive feet supplied), or mounted singly or
in pairs in the optional FAT-RACK 3U high 19” rack tray.
4OPERATION
4.1 What is Compression?
Compression is an essential but often misunderstood process in modern recording. Put
simply, compression reduces the ratio between the loudest and the quietest levels of an audio
signal, which is known as reducing the “dynamic range” of that signal. Before the introduction
of compressors the only way this could be achieved was by “gain riding”, whereby an
engineer would control the fader manually in order to try and anticipate very large levels
(which might distort the signal) or very low levels (which may get lost in noise). The
introduction of compression devices meant that this process could be controlled
automatically, allowing the engineer to get on with more productive jobs!

Many instruments and voices have a very wide dynamic range which needs to be controlled.
A singer, for instance, may be singing quietly one moment and very loudly the next, and
unless compression is applied the vocal won’t “sit” correctly in the mix, in addition to the
problems of distortion on loud passages and noise on quiet ones. Thus with compression you
are effectively turning down the loud bits and turning up the quiet bits, to achieve a more
even and controllable level.
But there are other benefits of compression as well -applied properly, it can add punch and
excitement to music, as well as fattening up sounds and creating a more professional
sounding recording. With the FAT 1, you have the added benefit of valve stages in the signal
path, which create a warmth and presence just not obtainable with solid state or digital
products.
4.2 Why Valve Compression?
Valve compression yields a particularly special sound which has become very sought after,
particularly with the widespread use of digital products. The reason valve equipment sounds
special is due to two things: harmonic distortion and natural compression. When the signal
through a valve is increased, it tends to generate a particular type of subtle and desirable
distortion, called “second harmonic” distortion. This has the effect of thickening and warming
the sound, and the more the level you feed to the valve stages, the more of this harmonic
distortion will be produced. You should be able to hear this effect as you increase the Input
Gain on the FAT 1.
Secondly, valves will tend to naturally compress an audio signal, again particularly as the
signal level is increased. This itself also contributes to the warmth produced by the FAT 1.
4.3 Overview of Compressor Operation.
The FAT 1 offers two distinct ways of working: manual or preset modes. In manual mode,
all the compressor controls are active and adjustable, so that compression settings can be
created from scratch to suit the user’s taste. In the fifteen preset modes, the Threshold,
Ratio, Attack, Release and Knee controls are disabled and each is fixed internally at a value
that is selected to give the best results with that particular instrument (the presets are titled
‘vocal’, ‘bass’, ‘guitar’, ‘snare’ etc. to indicate the recommended application).
The FAT 1 functions by reducing the gain of the signal when it rises above a certain level,
known as the Threshold. Any signal below the threshold passes through the unit unaffected.
Above the threshold the gain of the signal is reduced, and the degree of gain reduction is
determined by the Ratio control. The Ratio control is calibrated in dBs and is simply the
change in output level that results from a given change in input level.
The Attack and Release switches are used to control how fast the compressor reacts to the
audio signal. The Attack switch governs how quickly the FAT 1 acts to compress the signal

once it has risen above the threshold, while the Release switch controls how quickly the
signal returns to normal once it has dropped back below the threshold level.
The Knee switch controls the shape of the FAT 1 compression curve. In “Soft Knee” mode,
the response curve of the compressor around the threshold is gentle, so that the compression
effect is more subtle and musical. In “Hard Knee” mode, the curve is more severe, so that
signals above the threshold are “squashed” more aggressively. This yields a more audible and
pronounced compression effect.
The Gain Make-Up control is positioned at the output of the compressor stage, and allows
the signal level to be brought back to the same loudness as the uncompressed signal.
4.4 Input Gain.
The Input Gain control sets the level of the signal to the input stage of the compressor and is
variable between -20dB and +20dB. This allows a wide range of signals to be fed into the
FAT 1, and also allows the valve stages to be driven to a variable degree. Each channel of
the FAT 1 has a triode valve stage positioned between the input circuit and the compression
stage. Increasing the input gain pushes more signal level into the valve, thus generating more
harmonic distortion and creating that special “valve sound”. At the same time the output level
can be turned down to preserve the same level at the outputs, so a choice of sounds is
available. For a more pronounced valve sound, turn up the input gain and reduce the output
gain, and vice versa for a cleaner sound. Don’t be afraid to push the FAT 1 hard!
As well as driving the valves harder, increasing the Input Gain control setting will also tend to
push the signal towards and possibly over the compression threshold setting, so this control
will have a pronounced effect on the amount of compression taking place, even in the Preset
modes.
The Input Gain control is active at all times, whether the Program control is set to Manual or
Preset modes.
4.5 Output Gain.
This controls the level at the FAT 1 outputs, and again is variable between -20dB and
+20dB. This control effectively acts like an output fader, and is very useful when recording
direct to tape or hard disc through the FAT 1. You may find that some digital recorders
require a good deal of input level in order to register a 0dB reading on their meters. This is
normal, since many digital recorders are designed to preserve headroom and keep the signal
well below the 0dB clip point -thus preventing the recorder distorting. The FAT 1 provides
ample gain to drive digital recorders, but you may find that the Output Gain control has to be
set to higher levels for this reason (see also section 3.5 on operating level).
The Output Gain control is active at all times, whether the Program control is set to Manual
or Preset modes.

4.6 Gain Make Up.
While the subjective sound quality of the signal can be improved by compression, the overall
signal level will be reduced when gain reduction is taking place. The Gain Make Up control
is designed to boost the compressed signal by between 0 and 20dB, in order to bring back
the level to the same loudness as the uncompressed signal. Without this control, comparing
the original and compressed signals becomes difficult, since there would be a level drop each
time the compressor is switched in: therefore it is normal to adjust the Gain Make Up control
so that when the ‘compressor on’ switch is activated, the audio signal remains constant in
level.
Unlike the Output Level control, the Gain Make Up control is active only when the
‘compressor on’ switch is engaged. Once the Gain Make Up has been adjusted, use the
Output Level control to set the overall output level of the FAT 1.
Assuming the compressor is activated, the Gain Make Up control is active whether the
Program control is set to Manual or Preset modes.
4.7 Program Control.
This 16 way rotary switch enables factory preset compression settings to be selected for
different types of audio signal. The ‘Manual’ mode enables the Threshold, Ratio, Attack,
Release, and Knee controls to be adjusted, along with the Input Gain, Output Gain and Gain
Make Up controls (which are active at all times). In this mode the FAT 1 works like a
standard compressor in the sense that the user can create their own unique compression
setting and have full control over it at all times.
In all the other 15 program settings, the Threshold, Ratio, Attack, Release and Knee
controls are pre-selected and fixed within the FAT 1 to give optimum results for that given
type of signal. Thus these controls are disabled and will have no effect when adjusted, unless
the user returns to ‘Manual’ mode. In the Preset modes, all the user has to do is select the
required preset and then adjust the Input Gain, Output Gain and Gain Make Up to taste (see
particularly section 4.4 on Input Gain) The 15 presets are shown in Table 1.
The way the Program control works is by using a digital switching circuit to replace the
controls mentioned by a series of fixed components (in the case of Threshold and Ratio) and
on/off switch values (in the case of Attack, Release and Knee). This doesn’t mean that the
signal itself is converted to digital format within the FAT 1: it simply means that the signal
parameters are controlled digitally.
How did we create the Program settings? Simply by operating the unit in Manual mode and
arriving at an optimum set of adjustments for vocals, keyboards, basses, guitars, drums and
stereo mixes. These settings were then programmed into the FAT 1, and as a result we’ve

detailed the settings for each preset in Figure 4, should you wish to re-create any of the
presets in manual mode, and adjust them to suit your own application.

Table 1: Presets.
Number Preset Title Typical Applications
1 Vocal 1 Light, subtle compression for softer vocal
performances. Soft knee, fast attack and release.
2 Vocal 2 Medium compression for more obvious control. Soft
knee, fast attack and slow release.
3 Vocal 3 Hard compression for powerful performances. Hard
knee, fast attack and slow release.
4 Keyboards Designed for synth pads, strings etc. Soft knee, slow
attack and release.
5 Bass 1 Medium compression for electric, acoustic and synth
basses. Soft knee, slow attack and release.
6 Bass 2 Harder compression for electric, acoustic and synth
basses. Soft knee, slow attack and release.
7 Acoustic Guitar Soft knee, fast attack and fast release.
8 Electric Guitar 1 Medium compression for recorded or DI’d guitars.
Soft knee, fast attack and release.
9 Electric Guitar 2 Harder compression for recorded or DI’d guitars.
Hard knee, fast attack and release.
10 Snare Drum For tight control of snares. Hard knee, fast attack and
release.
11 Kick Drum For tight control of kick drums. Hard knee, fast attack
and release.
12 Kit Ideal for compressing stereo acoustic drum kits, drum
machines and sampler drum loops. Soft knee, fast
attack and release.
13 Mix 1 Lighter compression suitable for pop mixes. Soft
knee, fast attack and release.
14 Mix 2 Medium compression suitable for rock mixes. Soft
knee, fast attack and slow release.
15 Mix 3 Heavy compression suitable for dance mixes. Hard
knee, fast attack and slow release.
4.8 Threshold.
The FAT 1 functions by reducing the gain of the signal when it rises above a certain level,
known as the Threshold. Any signal below the Threshold passes through the unit unaffected,
while signals above the Threshold have their gain reduced (and are thus ‘compressed’).

The FAT 1 has a variable Threshold control, adjustable between +10dBu and -20dBu.
Unlike some compressors, the Threshold control on the FAT 1 starts at a ‘plus’ value in the
counter-clockwise position, and decreases to a ‘minus’ value as you rotate the control
clockwise. The reason for this is as you turn the Threshold control on the FAT 1 clockwise
(i.e. towards the negative region) then the degree of compression will increase. We think this
is logical, whereas the common method of turning the control ‘down’ to achieve more
compression is not -but beware, some other compressors may work in this way!
The Threshold control is only active when the Program control is set to Manual mode. In all
of the Preset modes it is disabled and the Threshold value is fixed internally.
4.9 Ratio.
Once the input signal has crossed the threshold, the degree of gain reduction is determined
by the Ratio control. The Ratio control is calibrated in dBs and is simply the change in output
level that results from a given change in input level. An uncompressed signal will have a 1:1
compression ratio -every 1dB change in input level results in the same 1dB change in output
level. A compression ratio of 1:3, for instance, means that a 3dB change in input level will
only give a 1dB change in output level. For more severe compression, simply turn up the
Ratio control.
The FAT 1 offers a wide range of ratios from 1:1.5 (gentle compression) through to 1:30
(limiting). Limiting effectively clamps the input signal at the threshold level no matter how
much the signal is increased: this can be useful when trying to ensure that the signal doesn’t
exceed a certain level -for instance to prevent a digital recorder distorting through overload.
The Ratio control is only active when the Program control is set to Manual mode. In all of
the Preset modes it is disabled and the Ratio value is fixed internally.
4.10 Attack and Release.
The Attack time of the FAT 1 is switchable between 0.5mS (‘Fast’) and 5mS (‘Slow’). At
0.5mS attack, the compressor is fast enough to compress a 1KHz signal in less than half a
cycle, effectively preventing the overload of any following equipment which has limited
headroom, such as a digital processor, tape machine or transmitter. Fast attack times are
used to compress a signal quickly, so are suitable for audio signals with sharper transients
such as drums. However, if you want the initial leading edge of the signal retained (for
instance the initial click of a bass guitar) then a slower attack time can be employed, and
slow attack times can also be useful on sustained sounds like synth pads.
The Release time of the FAT 1 is switchable between 0.2S (‘Fast’) and 1.5S (‘Slow’). The
Release setting is important because if it is too short, the compressor gain recovers too
quickly with the result that there is an audible ‘pumping’, ‘breathing’, and sometimes low
frequency distortion. In these cases try using a slow release time.

Adjustment of the attack and release times allows unobtrusive compression to be applied to
virtually any audio signal, but should very short transients occur the time constants become
signal dependent, generally reduced, to prevent a slow release leaving a ‘hole’ in the signal
after the transient. Also, a fast release setting will be extended by a slow attack setting. This
type of automatic control means that the flexibility of the FAT 1 is greatly extended without
the extra complication of fully variable attack and release controls.
The Attack and Release controls are only active when the Program control is set to Manual
mode. In all of the Preset modes they are disabled and the Attack and Release values are
fixed internally.
4.11 Knee.
The Knee switch enables the FAT 1 to be operated in two different modes -Soft Knee or
Hard Knee. Soft Knee mode offers a gentle compression curve around the threshold point,
and is traditionally employed to yield a more subtle, musical type of compression effect. The
Hard Knee setting causes the full compression ratio to be applied immediately the signal has
passed the threshold point, so tends to produce more pronounced and severe compression.
The Knee control is only active when the Program control is set to Manual mode. In all of
the Preset modes it is disabled and Knee setting is fixed internally.
4.12 Meter.
The FAT 1 is equipped with an illuminated VU meter. The Meter switch enables the FAT
1’s VU meter to monitor one of two parameters. When switched to ‘Output’ the meter
reads the audio output level, and is calibrated to read 0VU for a +4dBu output level. The
reference point may be internally adjusted by your dealer if required. Increasing the Output
Level control on the FAT 1 towards the +20dB setting will cause the FAT 1’s meter to
move further towards the red area and possibly to the end of the scale if sufficient gain is
applied. This is normal, particularly if driving a digital recorder where large input levels are
required.
The meter may be switched to indicate the amount of compression occurring. If the signal is
below the threshold, the meter will indicate 0dB: i.e. no gain reduction. As the signal passes
through the threshold, the meter will start to indicate the gain reduction at the compressor
stage (this will be a negative value, so the meter will move to the left, away from 0VU).
Note that this reading won’t include any extra gain make-up applied.
4.13 Compressor On.
This switch enables or disables the compressor stage, thus allowing an A/B comparison to
be made between the original untreated signal and the compressed signal. An associated
status LED indicates when the compressor is active.

5 GETTING STARTED
5.1 Connections.
There are various ways that the FAT 1 can be connected into your audio system. The three
most common are:
a) As an instrument front end
b) Connected to a channel insert point
c) Connected to a group or master insert point
To use the FAT 1 as an instrument front end, connect the output(s) of the FAT 1 directly to
the line (not mic) input of your console, recorder or sound card. The FAT 1 has balanced
line outputs for professional sound quality, but can easily connect to an unbalanced line input
(see Installation section 3.2). Once the outputs are connected, simply feed your instrument
into the front panel jack input(s) on the FAT 1. Recording direct to the multitrack recorder
(thus bypassing the console) is a common technique these days as it keeps the signal path
short, and of the highest quality. No unnecessary console stages are passed through, thus
maintaining quality.
Many mixers have sockets called ‘insert points’, which allow processors such as dynamics
devices and EQs to be patched in-line into the mixer signal path at various points. The most
common points that insert points are provided are in the channel, group and stereo master
sections. Patching the FAT 1 into the channel insert point means that any signal passing
through that channel will pass directly though the FAT 1. Compressing a vocal, for instance,
can be achieved by connecting the microphone directly to the console mic input, then
connecting the FAT 1 into the console insert point. The mic signal will be amplified by the
mixer before being passed into the FAT 1’s inputs via the mixer insert ‘send’ connection.
The outputs of the FAT 1 connect back to the insert ‘return’ connection, thus returning the
signal to the mixer and ensuring continuous signal flow.
Group insert points are used to compress sub-grouped signals such as drums or backing
vocals. It’s common to mix an entire drum kit to a stereo group, then use a pair of group
faders to control the overall level, rather than having to adjust each individual drum level. If
you then wish to compress the overall stereo kit signal, you can connect the FAT 1 to the
relevant group insert points, using the same ‘send and return’ technique as the channel insert.
Having compressed individual tracks while recording, it is common to apply compression to
the stereo mix while mastering it to 2 track tape, DAT or CD. Doing this will help fatten the
sound further and control levels. Like the channel and groups, the stereo L/R mix buss will
normally have a pair of insert points to facilitate this. If not, the FAT 1 can be connected in-
line with the mixer’s main stereo outputs, ahead of the master 2 track recorder.

5.2 In Use.
Having connected the FAT 1, it’s time to put it into action! Here’s a simple step by step
guide:
a) The first stage is to set up the gains of the unit. With the Compressor switched out, start
with the Input and Output Gains and Gain Make-Up at 0dB.
b) With the Meter set to read ‘Output’, adjust the Input Gain to achieve a peak reading of
around 0VU with the chosen source material.
c) If more output is then required then adjust the Output Level control accordingly.
d) Now depress the Compressor ‘On’ switch, and depress the Meter switch to read ‘Gain
Reduction’.
e) Using the Program control, select a suitable preset to suit the instrument or mix you are
listening to.
f) The meter should now register that some gain reduction is taking place. If not, or you
wish more gain reduction to occur, increase the setting of the Input Gain control.
g) When gain reduction is taking place, you should notice that the output level is reduced. By
switching the Compressor On switch in and out, you can compare the levels and the
subjective sound quality of the original and compressed signals. With the Compressor
active, use the Gain Make-Up control to set the level so that when disabling the
compressor, there is no level drop. This way you can A/B the signals without the levels
changing.
h) Switch to Manual mode. You will now find that the Threshold, Ratio, Attack, Release
and Knee controls become active. Start with the Threshold at +10dB, Ratio at 1:3,
Attack and Release at ‘Fast’, and Knee at ‘Soft’.
i) While continuing to meter gain reduction, gradually turn the Threshold clockwise towards
-20dB. While doing this you’ll notice that compression will start to take place and the
meter will start to register some gain reduction. The further towards -20dB you move, the
greater the gain reduction that occurs. Aim to get around a maximum 3-4dB of gain
reduction occurring as a starting point. You should also notice that increasing the Ratio
setting causes more gain reduction to occur.
By referring to Figure 4, you can see the settings that we have used to create the fifteen
program presets, so you may want to manually duplicate these settings and then use them
as a starting point, then adjust to suit your own tastes.

5.3 Frequently Asked Questions (FAQs).
Q: The FAT 1 is a stereo unit yet there is only one set of controls, Why is this?
A: The FAT 1’s single set of controls affect both channels simultaneously, since
the unit always works in linked stereo mode. To operate in mono mode, simply run
your mono signal through the left channel input/output (either the line input, or the
instrument input if applicable).
Q: The Threshold, Ratio, Attack, Release and Knee controls aren’t working.
A: This is because the Program control is not set to Manual mode, and these
parameters are all fixed within the FAT 1.
Q: Why is it I occasionally get some LF distortion on certain settings?
A: This happens when a Fast Release time is selected on certain bass-heavy
sources. The compressor is then forced in and out of gain reduction within an
individual cycle, and thus distortion is caused on the lower frequencies. Selecting a
slow attack/release time will cure the problem.
Q: Can I use the preset settings on instruments other than those recommended?
A: Absolutely. If it sounds good, use it!
Q: The Gain Make-Up control isn’t working.
A: This control is only active when the ‘Compressor On’ switch is engaged.
Q: The FAT 1 is a stereo unit but there is only one valve in it. Why?
A: The unit employs a single ECC83/12AX7A dual triode valve, so called
because it features two separate valve stages within one glass housing. Each
channel of the FAT 1 employs one of these stages.
Q: How long do the valves last before they need replacing?
A: This very much depends on the valve itself, whether the unit is left switched on
all the time and how much the unit is moved around. On average we’d say
about three years. The valve itself is easily sourced and relatively inexpensive -
contact your dealer for details.