SPL 9945, Channel One 9945 User Manual
Model 9945
Manual
Channel Strip
2
Manual Channel One
Model 9945
Version 1.1 - 5/2000
R & D:Ruben Tilgner
The information in this document has been carefully verified and is
assumed to be correct. However Sound Performance Lab (SPL) reserves the
right to modify the product described in this manual at any time. Changes
without notice.This document is the property of SPL and may not be copied
or reproduced in any manner,in part or full without the authorisation of SPL.
Limitations of Liability:
In no event will SPL be liable for any damages, including loss of data, lost
profits, cost of cover or other special, incidental, consequential or indirect
damages arising from the use of the unit, however caused and on any theory
of liability.This limitation will apply even if SPL or an authorised dealer has
been advised of the possibility of such damage.
Sound Performance Lab
P.O.Box 12 27
D- 41368 Niederkruechten, Germany
Phone +49 - 21 63 / 98 34-0
Fax +49 - 21 63 / 98 34-20
eMail: info@soundperformancelab.com
www.soundperformancelab.com
© 2000 SPL electronics GnbH. All Rights Reserved. Subject to change without notice.
3
Contents
Introduction ................................................................................................................... 4
Principles ......................................................................................................................... 4
Hookup ............................................................................................................................. 5
Connections:
Rear front / Wiring .......................................................................................................... 6
General advises / Connectors ..................................................................................... 7
Operation:
• Preamplifier
Microphone Gain, 48 Volt phantom power, phase reverse,high pass ........... 9
Highpass,Instrument Gain,About levelling,
Instr./Line On - MicOff,Instr. Input ............................................................................10
• De-Esser
On,S-Reduction,Technical Information regarding De-Esser ............................11
• Insert
Insert ..................................................................................................................................12
• Compressor/Limiter
On .......................................................................................................................................12
Limit,Gain Reduction, Noise Gate ............................................................................13
Make Up,Technical Information regarding the Compressor/Limiter .............14
• Equalizer
On,Pre Comp.,Air Band ...............................................................................................15
Mid-Hi Band,Cut/Boost (Mid-Hi),Low Band,Cut/Boost (Low) .........................16
Tip for frequency setting,Distortion ........................................................................17
• Output
Output,Mute ...................................................................................................................18
• Headphone Monitor
Playback,Volume,Phones ...........................................................................................19
• Displays
S-Detect., Clip, Signal,Warm Up .................................................................................20
Gain Reduction, PPM-Output .....................................................................................21
Power supply .................................................................................................................21
Specifications ...............................................................................................................22
Block Diagram ..............................................................................................................23
Measurements ..............................................................................................................24
Warranty ..........................................................................................................................26
Copy Master ...................................................................................................................27
Notes .................................................................................................................................28
4
Introduction
SPL is mainly known for the development of highly specialized audio-tools.
Our philosophy, ”one product for one task”,is aimed at fast and simple operation in conjunction with high processing quality, to ensure highest musical
performance.
With Channel One SPL have produced a complete channel strip which for
the greater part is based on the processing concepts already successfully
realized in other products. The very complex task of a channel strip profits
particularly from the innovative techniques that have always allowed the
operation of SPL equipment to be efficient and objective.The ususal recording day is to a high degree determined by a series of opposing time limits –
the ”highly paid” singer/speaker desires a quick recording; however, if technical preparation takes a long time because of unsuitable equipment, time
will be lost, increasing the costs and souring the working environment.The
Channel One in all cases however allows fast production without any loss of
professional precision and diligence.
The Channel One consists of a transistor/tube pre-amplifier with microphone-, line- and instrumental inputs, a de-esser, a compressor/limiter with
noise gate,an equalizer (EQ) section and a headphone monitor.
The Channel One has all necessary tools on board to prepare a recording for
a digital recording system.It offers many possibilities for sound processing –
the total bandwidth of subtle corrections to low-fidelity sounds is available.
The versatility and completeness of the unit permits its use in additional
areas, over and above the purely ”recording channel”facility, for instance in
mixdown,as high quality single outboard EQ or compressor.
To maximize user friendliness and for clarity all modules have been
reduced to the most important regulating and switching facilities. Fast and
effective operation is in no way impeded, quite the opposite – it´s
supported.More time remains to work creatively.
Great value was placed from the outset on high flexibility. An example of
this is the 3 separate inputs for microphone,line-signals or instruments,each
of which has been optimized to its function.
A twin triode tube is utilized in the process at 2 points – one immediately
after the amplifier stage and the other at the end of the chain, so that the
processed signal passes once again through the tube stage. This construction combines the advantages of the transistor pre-amplifier stage (high
performance with minimal distortions and low noise levels) with the
improved musical expression of the tone produced by tubes.
The microphone input can be optionally provided with Lundahl input
transformers. The input transformers deliver a five times enhanced microphone level to the pre-amplifier, an amplification which reduces the equivalent load to the electronic pre-amplifier. The balanced outputs can also be
equipped with Lundahl transformers, which deliver an even warmer and
fuller sound.
Principles
5
Principles
Hookup
A 24 Bit/96 kHz AD/DA module can optionally be provided to enable immediate digital recording.With this AD/DA converter a complete digital insert is
also possible. An additional socket on the Channel One serves the purpose
of delivering a further signal source to the AD converter.
In order to quickly determine all signal conditions, displays for level, gain
reduction, S-detection, clip, warm-up and signal are combined and
contained in a clearly defined display area.
A special feature of the printed circuitry layout is the central star ground
wiring scheme:
Disturbing influences that could affect the ground paths are minimized in
that the audio-ground is separated from the ground of the remaining equipment. This leads, in the truest sense of the word ”clean”, to considerably
improved tonal quality.The scatter free toroidal transformer, manufactured
to SPL tolerances, supplies the equipment with the necessary voltages and
forms the basis for a clean electrical supply to all parts of the circuitry.
Carefully select a place for setting up the Channel One. The unit should be
situated away from heat sources and direct sunlight. Avoid installation in
environments exposed to vibrations, dust, heat, cold or moisture. Keep the
unit away from transformers or motors or any other unit that could generate
large variations in power supply or cause electrical interferences. Do not
install the unit in proximity to power amplifiers or digital processors. You
may consider placing it in a rack containing other analog gear. Such placement can prevent interference from Word Clock,Smpte, MIDI,etc.
• Do not open the case. You may risk electric shock and may damage your
equipment.
• Leave repairs and maintenance to a qualified service technician. Should
foreign objects fall inside the case,contact your authorised dealer or support
person.
• To avoid electric shock or fire hazards do not expose your unit to rain or
dampness.
• In case of lightning unplug the unit. Please unplug the cable by pulling on
the plug only; never pull on the cable.
• Never force a switch or knob.
• To clean the case use a lint-free cloth. Avoid cleaning agents as they may
damage the chassis. Manufactured in standard 19" EIA format, it utilises two
rack units.
• Please support the back of the unit whenever it is being mounted into a 19"
rack (especially important when touring).
6
Connections
Rear Front / Wiring
7
Connections
General Advises
Connections
Connectors
Again, while Channel One’s housing is EMV-proof and protects against HFinterference,placement of the unit is very important since it amplifies microphone signals as well as other unwanted signals. Before connecting the
Channel One or any other equipment turn off all power. Adjust the voltage
setting on the back so that it corresponds with the power conditions.
The following graph shows the correct wiring for connecting unbalanced
signals to the balanced XLR connectors:
Unbalanced signals with mono jack plugs may easily be connected to the
balanced jack connectors without level differences (see “Analog Outputs“ on
page 8).
Mic connector
The Mic connector is used to plug in microphones of any type (dynamic,
condenser or tube microphones etc.). If 48 V phantom power is required for
some mics, switch on the 48 V button. For further information please read
“48 V-phantom power“ on page 9.
Line connector
The balanced Line connector serves to connect line level equipment. It is
recommended to route the Line input to a patchbay. This allows easy and
fast selection of various line signal sources.
Insert connectors
The balanced Insert connectors (Send and Return) are used to integrate
further units into the signal path of the Channel One.The Send connector is
placed behind the De-Esser, the Return connector is located in front of the
Compressor/Limiter. This also allows to record the pre-amplifier signal via
the Send connector while another input signal can be fed into the Channel
One’s Compressor/Limiter/EQ sections for further processing.
8
Connections
Connectors
Analog Outputs
The Analog Outputs deliver balanced output signals. Lundahl output transformers can be equipped optionally.
Since both connectors are working in parallel, unbalancing one connector
also unbalances the other one.If for example a mono jack plug is connected
to the jack connector, the XLR connector is switched to unbalanced operation as well.
A/D Input 2
This connector serves to feed a further signal to the optional AD/DA
converter. Two different signals can be converted at the same time. If no
signal is fed to the A/D Input 2 connector,the output signal of the Channel
One is routed to both channels of the converter.The maximum input level
should not exceed +12dBu to avoid clipping of the converter (+12dBu
represents the digital full scale level,0 dBfs).
Playback Inputs
The playback signal is connected to the unbalanced Playback Input jacks to
direct it to the Headphone Monitor. If a mono playback signal is available,
only the Left connector must be connected.The signal will then be present
on both channels. The Right connector should be used, if only one channel
should appear on one side of the headphones. In contrast to all other
connectors the Playback Inputs are unbalanced.
GND Lift
The GND Lift switch separates internal ground from chassis ground. The
switch should be activated to eliminate ground loop humming which may
occur if the Channel One is connected to units with another ground potential.
9
Operation
Pre-amplifier
Microphone Gain
The Microphone Gain control determines the preamplification of the microphone signal. The preamplification values extend up to + 65 dB. If Lundahl
input transformers are fitted the scale values are to be increased by + 14 dB.
Please refer to "About levelling" on page 10 for further information.
48 Volt phantom power
The 48 Volt phantom power in the Channel One serves to supply condenser
microphones which are equipped with in-built preamplifiers. A precise
construction and disturbance free electrical supply are the main requirements for their trouble free operation. In the Channel One the voltage is
maintained at a precise 48 V and delivers a maximum current of 14mA. This
is sufficient for all types of microphones.
WARNING:All microphones with balanced, ground free output (including
tube microphones) can be operated with phantom power switched on.The
following procedure is to be adhered to: Firstly connect the microphone to
the Channel One, then switch on the phantom power – you can now
commence work.When recording has been completed firstly switch off the
phantom power then wait 30 seconds before disconnecting the microphone from the Channel One.This allows residual voltages to be discharged.
Phantom powering is only used with condenser microphones.With any
other type of microphone it is to be switched off ! An unbalanced microphone is not to be used with phantom power switched on!
Phase Reverse
The phase inversion function reverses the polarity of the microphone signal.
When the button is pressed the phase is rotated through 180º.The phase
inversion function is often useful, for instance to correct a headphone
monitor signal which is possibly wrongly phased. A singer/speaker can
actually hear himself during recording as well as over the headphones.
Incorrect polarity leads to an unnatural tone and to drastic tonal changes, if
the distance to the microphone is varied.We recommend that you check the
polarity and correct it if necessary before commencing recording.
Loading...