Overstayer IMPERIAL CHANNEL 877 Series Operator's manual

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IMPERIAL CHANNEL 8776A
REFERENCE v1.1
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INTRODUCTION
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The 877 series modules are self powered, self contained channels that can be used on their
own (no chassis required) or as part of a larger framework for recording and mixing.
The 8776A features mic, line, and instrument inputs, as well as filters, 4 band eq, FET limiting,
and controls to shape and exploit the harmonic character of the circuitry throughout. Modules
can be mounted vertically in dual, quad, or a 10 space rack-mountable chassis (5RU high).
Audio connections are via XLR and TRS connectors with access to several points in the signal
path.
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The Imperial Channel’s preamp and drive amps were inspired by late 60’s English solid state
consoles. Their primitive design makes them incredibly forgiving with a wide range of
nonlinearities before overt clipping (a wide sweet spot), and with that they are generous with
low order harmonics, and can be driven into full distortion. These stages are ‘cushioned’ in this
design allowing them to be used exploited in new ways.
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The concept of the channel is to have a fluid interactive chain, where creative decisions can be
made by immediately by turning controls and switches. Multiple stages distribute the rounding
and harmonics, each with different characters. The HARMONICS stage at the end of the chain
has MAS circuitry, and can ‘control’ peaks, and smooth harsh frequencies, allowing the
equalizer for instance to be approached creatively and aggressively. As an example, the
proportional Q bells have a large amount of gain and can be driven almost to the point of
oscillation, which can sound raw on its own, but driven into the harmonics circuitry can be
‘absorbed into the signal and become a band of harmonic distortion.
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FEATURES
●Microphone, line, and instrument inputs
●Transformer coupled input and output
●Multiple discrete gain stages
●High and low pass filters
●4 band equalizer with high and low shelving boosts, and 2 fully sweepable mid bands
●FET Limiting Amplifier with sidechain filter and 3 position attack and release controls
●MAS harmonics
●Independent preamp (dry) and channel (wet) output faders for parallel processing
●Polarity, pad and phantom power
●4 segment level and gain reduction metering
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Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

SAFETY AND INSTALLATION
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Installation
1. Before attaching the DC plug of an adaptor to equipment, please unplug the adaptor
from the AC power and verify the unit is within the voltage and current rating on the
equipment.
2. Keep the linkage between the adaptor and its power cord tightly as well as connecting
the DC plug to equipment properly.
3. Protect the power cord from being trodden on or being squashed.
4. Use only an approved power cord, do not defeat the safety grounding pin which must
be connected to earth at all times (do not use a ground lift).
5. Keep good ventilation for the unit in use to prevent it from overheating. Do not install
near any heat source or device that produces heat.
6. An approved power cord should greater or equal to SVT, 3G×18AWG or H03VV-F,
3G×0.75mm2.
7. If the final equipment is not used for long period of time, disconnect the equipment
from power supply to avoid being damaged by voltage peaks or lightning strike.
Warning / Caution !!
1. Risk of electrical shock and energy hazard. All failure should be examined by a qualified
technician. Please do not remove the case of the adaptor by yourself!
2. Risk of fire or electrical shock. The openings should be protected from foreign objects
or dripping liquids.
3. Using wrong DC plug or forcing a DC plug into an electronic device may damage the
device or cause to malfunction.
4. Adaptors should be placed on a reliable surface. A drop or fall could cause damage.
5. Do not use or install in places with high moisture or near the water.
6. Do not use or install in places with high ambient temperature or near fire source.
7. Disconnect the unit from the AC power before cleaning. Do not use any liquid or
aerosol.
8. Please contact your local qualified recyclers when you want to dispose this product.
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Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

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GETTING STARTED
To get a sense of the signal flow and gain structure, you can start
with the settings pictured, which uses the balanced LINE IN A
input, but the process is the same for MIC and INST.
PREAMP GAIN
To set the preamp gain, adjust DRIVE to 0, CHANNEL fader (upper)
to 10, and the meter switch to VU1. EQ, HPF, LPF, LIM, and HARM
should all be bypassed. Adjust the GAIN control for roughly unity,
which should fall between 1 and 3 leds on the meter (4 is at
clipping).
EQUALIZER
Adjust the CHANNEL fader down to ~7/8 to give some headroom
(especially for low boosts), and engage the EQ to the middle
position (EQ IN). The EQ is capable of large boosts, so you may
also need to adjust the GAIN to maintain headroom. You can
sweep the shelves, which are passive and broad to get a feel. The
bells are proportional Q and have a wide frequency and boost/cut
range. This allows them to be used ‘sensibly’ but also in their
extremes of gain approach self oscillation. The EQ IN switch up
position is a special mode that allows cleaner low boosts at higher
DRIVE settings.
HARMONICS
Engage HARM (middle position is stronger 3rd, upper 2nd) to see
how it interacts and can ‘control’ the eq boosts. Increase DRIVE,
compensating with the CHANNEL fader to get it’s feel, with and
without HARM engaged. The threshold of the HARM circuitry is
lower than the threshold of the DRIVE amplifier, so it can be
driven somewhat cleanly if desired. The HARM smooths, rounds
peaks, and generates low order harmonics, and is critical in that it
allows all the blocks ahead of it (Filters, EQ, Limiter) to be used
more broadly (somewhat of a safety net to get wild).
DRIVE
DRIVE is post shelves and pre bells, so you can shape tonally into
it and after it. Increase DRIVE, compensating with the CHANNEL
fader to get it’s feel, with and without HARM engaged. DRIVE is
post shelves and pre bells, so you can shape tonally into it and
after it. The threshold of the HARM circuitry is lower than the
threshold of the DRIVE amplifier, so it can be driven somewhat
cleanly if desired. DRIVE can go deep into distortion, and
experimenting with HARM settings has a dramatic effect on how
raw or smooth this can sound.
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Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

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LIMITER
Set DRIVE back close to 0, and engage the LIM IN, then adjust the LIM IN control to set the
desired amount of limiting, and compensate with the LIM OUT control. Setting the LIM IN
switch to the top SC HPF position engages the limiter with a hpf on the sidechain. Set the
meter switch to LIM to show gain reduction on the meter. The limiter comes after the eq and
DRIVE, and before the HARM circuits, so when it is engaged, DRIVE effects how hard the limiter
is driven, and LIM OUT effects how hard HARM is driven.
PARALLEL MIXING
The PREAMP fader, which is essentially a dry signal (unless the GAIN is overdriven) allows the
parallel mixing with the fully processed CHANNEL fader and the dry MIX fader. The faders are
additive so they may require balancing to maintain headroom. The preamp fader has an
access point on the rear panel, and any other signal from the unit (EQ, or LIMITER for
example) can be patched here. An external signal (effects, pedal, etc.) can also be patched
here.
*The Imperial Channel is as much an instrument as a classic channel. It has several gain stages
that are collectively capable of massive amounts of gain. High and low frequency instability
and noise are possible especially at high gain settings, extreme limiting, and LMF shelf boosts,
so be aware to keep headphone and speaker levels in check at all times.
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Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

SIGNAL FLOW
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Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

FRONT PANEL CONTROLS
INPUT SWITCH
LINE - Selects the balanced line input as the source (LINE IN A), in
this mode unity will be ~8 on the GAIN control.
-20 - Selects the microphone input as the source, padded 20 dB
MIC - Selects the microphone input as the source.
INSTRUMENT INPUT, POLARITY SWITCH
INST IN -Selects the high impedance unbalanced INST IN as the
source, over-riding the LINE, -20, MIC switch. If nothing is plugged
into the INST IN connector, the source is unbalanced LINE IN B,
which can accept higher level signals than the INST IN, and can be
better for synths, drum machines, etc. that have higher output
levels.
POLARITY +/- - Changes the polarity of the balanced LINE or MIC
signal.
PHNT - Engages phantom power to the microphone input.
GAIN - Controls the amount of preamp gain.
DRIVE - Controls the gain of the DRIVE amplifier (unity is 0), which is
post shelves (HF BOOST, LF BOOST), and pre bells (HMF, LMF).
FILTERS
HPF - High pass filter selectable between 75Hz, 150Hz, and bypass.
LPF - Low pass filter selectable between 7K5Hz, 15KHz, and bypass.
TRANSFORMER CURVE - Changes the response curve of the output
transformer, 50Hz rolloff with a resonant peak (loading dependent)
EQUALIZER
EQ IN - 3 positions, bypass, EQ in, EQ with curve.
HF BOOST - High frequency shelf boost with 3 selectable
frequencies, 5KHz, 10KHz, 15KHz.
LF BOOST - Low frequency shelf boost with 3 selectable frequencies,
50Hz, 100Hz, 200Hz.
HMF DB/KHZ - High mid frequency bell with >20dB of boost or cut.
LMF DB/KHZ - Low mid frequency band with >20dB of boost or cut.
LMF SHLF - Changes the low mid bell to a low shelf.
LIMITING AMPLIFIER - FET limiter with input (inside) and output
(outside) level controls. Features a selectable 200Hz sidechain high
pass filter and 3 position attack and release controls.
HARMONICS - MAS harmonics stage selectable between stronger
2nd harmonic, stronger 3rd harmonic, and bypass.
PARALLEL FADERS - Dual output faders, one for the full channel
path (wet), and one fed directly from the preamp (dry) for parallel
compositing within the channel.
Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

METER SOURCE - Selects between the preamp (VU1), harmonics (VU2), and gain reduction
(LIM).
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REAR PANEL CONNECTIONS
The 8776A has extensive audio interconnects on the rear panel. Each
circuit block has its own input and half normalled output, allowing
multiple signals to be recorded simultaneously, as well as allowing
the signal flow to be re-configured with patch cables.
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MIC IN
Balanced transformer coupled microphone input.
LINE IN A
Balanced transformer coupled line input.
LINE IN B
Unbalanced line input.
INST IN
Unbalanced high impedance instrument input.
PREAMP OUT
Direct output post HPF.
EQ IN
Direct input pre Equalizer, normalled to the PREAMP OUT.
EQ OUT
Direct output post Equalizer.
COMP IN
Direct input pre Limiter, normalled to EQ OUT.
COMP OUT
Direct output post Limiter.
HARM IN
Input pre Harmonics, normalled to COMP OUT.
HARM OUT
Direct output post Harmonics.
LINE OUT
Balanced transformer coupled line output.
AUX
The AUX jack provides access to the PREAMP (dry) fader, allowing an
alternate signal to be mixed in, either from another point in the unit,
or externally (pedals, etc.).
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Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice

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8776A PATCHING EXAMPLES
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EXAMPLE 1 (left) - Re-arranges the signal path to put the LIMITER before the EQ.
EXAMPLE 2 (middle) - Makes the PREAMP fader (dry) post EQ. Alternately the AUX can be fed
from the COMP OUT to blend the Limiter with the Harmonics.
EXAMPLE 3 (right) - Allows an external device to be blended in parallel using the PREAMP
fader. The external device can be fed from any output in the signal path.
Copyright © 2018, Overstayer Recording Equipment, Inc.. All rights reserved. All features and specifications subject to change without notice