Gainlab Audio BISHOP User manual

Op OPERATION AND SAFETY PRECAUTIONS
■Use only grounded electrical outlet!
■Do not open the device and don’t do any modifications on it!
■Do not attempt to repair or replace any of the components unless
specifically instructed to do so in this guide.
■Pay attention to not put any solid matter (flammable things, coin,
nail etc) or liquid (water, alcohol etc.) inside device.
■Do not twist or break the power cord or place heavy objects on it.
Doing so may damage the cable and cause a short circuit.
Damaged cables can cause fire and electric shock!
■Protect the device from intesive external shock! (for example:
falling down)
Never use the device in following conditions:
■Extreme temperature
■Moisture
■High humidity
■Rain
■Dust
■Heavy vibration
In the following cases, turn off the machine immediately, unplug the
power cord, and contact us ([email protected]):
■If the mains plug of the appliance is damaged
■If you notice smoke or an unusual odor
■If any object or liquid gets inside the device,
PLEASE NOTE THAT THE GLA-MP1 BISHOP IS INTENDED FOR PROFESSIONAL
USE. IT’S NOT A CONSUMER ELECTRONIC DEVICE. ITS INSTALLATION AND USE
REQUIRE CERTAIN PROFESSIONAL SOUND ENGINEERING KNOWLEDGE AND
SKILLS. LACK OF THIS KNOWLEDGE MAY RESULT IN MALFUNCTION, DAMAGE OR
PERSONAL INJURY.

■If the device has been exposed to rain or other moisture,
■If the device does not operate normally
■Do not connect the appliance to a mains socket to which an
electrical appliance controlled by an inverter, switching power
supply (eg. refrigerator, washing machine, microwave, air
conditioner) or a appliance with a motor is connected.
■Depending on the use of the electrical devices, power supply
noises may cause a malfunction or audible noise on this unit. If a
separate electrical outlet cannot be used, connect a noise filter
between this and the other electrical appliance.
■The unit heats up during several hours of continuous
operation. This is normal and not a cause for concern.
■Turn off all devices before connecting the device to other devices.
This will prevent damage to speakers and other equipment.
■Use of the unit near amplifiers or other equipment that contains a
transformer may cause noise. To resolve this issue, relocate the
device or move it away from the interfering device.
■Noise may be caused by using a wireless communication device
near the device, such as a mobile phone. Such noise can occur
when making, receiving, and diverting a call. If you experience this
problem, move the wireless device away from the device or turn it
off.
■This unit may interfere with radio and television operation, so do
not use near such receivers.
■If the device is transported to a location with a very different
temperature and / or humidity, moisture may condense inside.
Using the device in this condition may result in damage or
malfunction. Therefore, wait a few hours for the moisture to
completely evaporate before using the appliance.
Cl CLEANING AND MAINTENANCE
Clean the appliance daily with a soft, dry or slightly damp cloth. Use a
soft, abrasion-free cloth to remove stubborn dirt. Then wipe the device
with a dry cloth. Never use benzine, thinner, alcohol or other solvents,
strong alkaline or acidic cleaners as they may cause discoloration and
deformation.

In INTRODUCTION
The BISHOP All Tube Channel Strip is a fully symmetrically designed
recording channel with an All Tube system, featuring a two-stage
amplification, dynamic processing, and tone control options.
Symmetrical in nature, it does not asymmetrically alter the received
balanced signal. All Tube implies that only electronic tubes are involved
in the amplification process. It's two-stage because it can engage a
secondary stage alongside the main amplification stage for greater gain
if desired. It is equipped with a dual slope optical compressor, each with
individually adjustable threshold points. It features a two-position AIR
band switch capable of emphasizing high frequencies. When combined
with the dynamics control, it can achieve all of this within the context of
the audio material. As the gain reduction on the compressor increases, a
corresponding boost occurs in the high frequencies.
Ps PREAMP SECTION
The main control element of the
preamp section is the dual gain
selector knob located on the left
side of the VU meter. This knob
regulates the preamp gain and
facilitates switching between the
different preamp stages. The internal
scale, which we refer to as the Low
PREAMP SECTION TONE CONTROL SECTION
DYNAMICS SECTION
INPUT SELECTION
PREAMP AUX.

Gain scale, handles amplification ranging from +6dB to +40dB and can
be accessed by setting the Gain switch to the lower position. The
external scale, known as the High Gain scale, manages amplification
between +26dB and +60dB and is accessible by toggling the Gain switch
to the upper position. In High Gain mode, alongside the primary preamp
stage, a secondary stage capable of +20dB gain is activated. The
illuminated scale indicator clearly shows which mode is currently
active. The Low Gain mode boasts significantly better signal-to-noise
ratio and distortion values compared to the High Gain mode. The choice
of mode depends on the required level of amplification for the given
situation. For amplification needs maximum of +40dB, the use of Low
Gain mode is recommended, as it suffices for most recording scenarios.
Px PREAMP AUXILIARY FUNCTIONS
The additional functions of the preamp
are situated around the Power switch
on the left side of the front panel. The
PAD switch engages a -20dB attenuator
to handle potentially excessive input
signals that the Bishop might
encounter. The Phase switch inverts the
polarity of the incoming signal, which
can effectively address intermodulation
issues arising from variations in
microphone placement, especially in
multi-microphone recording setups.
The Phantom Power switch activates
the power supply of +48V required for
microphones that rely on it. Most
condenser microphones necessitate this type of power supply, while the
majority of dynamic microphones do not.
PRIOR TO ENABLING PHANTOM POWER, PLEASE VERIFY WHETHER THE CONNECTED
MICROPHONE REQUIRES THIS KIND OF SUPPLY. CONNECTING PHANTOM POWER TO
A MICROPHONE THAT DOESN'T NEED IT CAN LEAD TO DAMAGE.

Nt NOTE: GROUND THE RECEIVING SIDE
If the Bishop has a microphone connected to it with an external power
supply, there is a possibility that a so-called ground loop may form
between the Bishop's power supply and the external microphone's
power supply, which can have an undesirable impact on the signal-to-
noise ratio. In such a case, the "always ground the receiving side" rule
comes into play. Therefore, on the sending side, which is the side of the
microphone's power supply, the ground lift switch must be used, or a
cable should be used that breaks the grounding on the microphone's
power supply side. Additionally, there is the option to use a ground lift
adapter connector as well.
So SIGNAL SOURCE SELECTION
The signal source selector can
be found to the left of the Gain
Mode selector switch. In its
center position, which is the
default setting, the Bishop
expects a microphone-level
balanced signal at its input. In
the lower position, it anticipates
a symmetrical or asymmetrical
line-level signal for the preamp.
The upper position, on the other
hand, is intended for instrument
input. The instrument input is

designed for high-impedance asymmetrical signals, which are further
linked to the preamp via a matching buffer. The gain of the input buffer
can be adjusted using the Drive potentiometer. The appropriate Drive
parameter will vary based on the internal structure of the connected
instrument. It is strongly recommended to utilize the instrument input in
Low Gain mode, alongside an appropriate Drive setting, as this approach
maintains the signal-to-noise ratio at a manageable level due to the
asymmetrical signal and high impedance.
When it comes to connecting
input sources, it's possible to
connect microphone and line
signals to both the front and rear
panel connectors, while the
instrument input is only available via the
combined front panel connector. Generally, devices connected to the
front panel always take priority. For instance, if microphones are
connected to both the front and rear panel inputs, the microphone
connected to the rear panel input will remain inactive until the
microphone connected to the front panel input is disconnected.
Dc DYNAMICS CONTROL SECTION
Moving to the right of the VU meter, you will find the instruments and
controls of the optical compressor directly. The compressor can be
activated or deactivated using the switch located below the reduction
meters. The compressor in the Bishop utilizes optical compression,
employing Light Dependent Resistors (LDRs) for dynamic control,
similar to units like the LA2A or CL1B. While most dynamics processors
allow for setting a single threshold point, the Bishop's compressor
enables the setup of two threshold points, which is why we refer to it as
a Dual Slope optical compressor.
A typical use of this compressor involves applying the majority of
dynamic control on the first knee of the curve, followed by a much
steeper second knee to handle sudden and abrupt amplitudes. This
approach allows the compressor's sound to remain manageable and
LINE INPUT MIC. INPUT

natural even under extreme operating parameters and level changes. In
terms of controls, the adjustment of the first threshold point is achieved
through the Threshold knob, with the corresponding gain reduction value
indicated by the meter labeled GR1. The setting of the second threshold
point is accomplished using the 2ND Slope knob, with the gain reduction
value for this indicated by the GR2 meter.
As this isn't two separate compressors but rather a single extensively
parameterizable dynamics processor, the gain reduction for each slope
can change depending on the level distance between the individual
threshold points and how the audio material fills this range. Therefore,
it's advisable to review the first threshold point setting after adjusting
the 2ND Slope.
The Bishop's compressor primarily serves as a supplementary
component to the preamp. The setting of compression ratio and knee
value is done simultaneously using the Character switch, which offers
three levels (Soft/Medium/Hard). As you progress through the levels, the
compression ratio increases and the knee curve becomes sharper.
Adjusting the compressor's timing is achieved via the Time Constant
rotary switch, which offers six positions as presets. The first automatic
mode attempts to determine the timings based on the nature of the
incoming audio material. The remaining five positions offer attack and
release values from fastest to slowest. If you wish to use two Bishops
simultaneously while having both compressors engaged, it may be
necessary to link the compressors of the two units. This can be achieved
using the SC.Link connector located on the back of the Bishop, using an
asymmetric Jack-Jack cable. In terms of practical implementation, it's
advisable to proceed as follows:

1. Connect the two Bishops using the Jack-Jack cable.
2. Set the Character and Time Constant rotary
switches to the same position on both units.
3. On one unit, leave the Threshold and 2ND Slope
knobs in their default positions, while on the other
unit, adjust the desired reduction values for both
slopes.
As a result, both Bishops will display similar reduction values, depending
on the signal entering the compressors, of course.
Oa OUTPUT ATTENUATOR
Located below the tone control section is the rotary
switch for the output attenuator. This allows us to
create a -12dB attenuation in 5 steps on the Bishop's
output. This can often be useful, for instance, to
compensate for the gain reduction caused by the
compressor. By adjusting the preamp's Gain control
upwards while using the output attenuator, and then
depending on the compressor's gain reduction,
turning down the output attenuator, we can achieve
the output level before compression.
OUTPUT LINE INPUT MIC. INPUT
SC. LINK
OUTPUT LINE INPUT MIC. INPUT
SC. LINK
SIGNAL
GROUND
SIGNAL
GROUND

Tc TONE CONTROL SECTION
On the top right side of the Bishop, you'll find
the controls for the filter section, which
determine the tonal characteristics of the
sound processed by the Bishop. The HPF
switch activates a simple high-pass filter
designed to eliminate potential muddiness in
the low-frequency range. One common issue
this can address is the proximity effect often
seen with large-diaphragm condenser
microphones. We recommend starting with
lower frequency values when experimenting with this. In this case, begin
with a 60Hz low-cut filter, and if that doesn't resolve the issue, then
switch to 120Hz.
The DynAir switch engages the AIR band in two positions. This results in
a gently rising shelving filter with a very natural sound. When using the
Air function, it's a good idea to begin by adjusting higher frequencies.
Start with 30kHz first, and if you're not satisfied with the result, then try
experimenting with 20kHz.
When using the Air function in conjunction with the built-in compressor,
you'll notice that the effect produced by the Air function isn't constant;
rather, it depends on the current gain reduction value of the compressor.
The relationship is such that as the gain reduction increases, the Air
band boosts more.
YOU CAN FIND DETAILED INFORMATION
ABOUT THE PRODUCT IN THE BISHOP USER MANUAL. IF YOU HAVE ANY QUESTIONS,
FEEL FREE TO REACH OUT TO US ON THIS PAGE.
WWW.GAINLABAUDIO.COM