Features and Specification - SQN-5S
Mixer
Inputs
|
Five transformerless balanced inputs using XLR-3 type
female connectors. Each channel is switchable for:
-
Powering:
- a) 12V T (Din AB)
- b) 12V Phantom
- c) 48V Phantom
- d) Dynamic (150 to 600 Ohms)
-
Attenuation:
- 0dB, -10dB or -20dB
Setting an internal switch on each channel enables
automatic insertion of an extra 10dB of attenuation
when mic powering is selected. This is achieved
without compromising the noise performance of the
microphone.
-
Bass Cut:
- Flat, -6dB or -16dB at 50Hz
-
Line Attenuation:
- Adds 50dB attenuation before the mic
preamp.
|
| Sensitivity |
-78dBu for nominal line level (PPM4, 0VU)
with the channel gain at maximum and the master gain at
0dB |
| Max Level, Mic Inputs |
-20dBu (+4dBu with full attenuation) |
| Noise Figure |
-130dBu (A weighted) from a 200 Ohm
source. |
| Frequency Response |
20Hz to 20kHz +0, -1dB, referred to
1kHz. |
| Crosstalk |
Isolation, channel to unrelated channel:
75dB at 1kHz, 60dB at 15kHz. |
| Channel Configuration |
The mixer has five input channels, all of
which have the same input selectors, bass cuts and
attenuators. The routing arrangements for CH1 & 2
differ from those for CH3, 4 & 5. |
Channels 1 & 2
[GANG 1-2] |
The operation of the CH1, CH2 pair is controlled by the
GANG 1-2 switch on the front panel. This switch has three
positions:
- Twin MONO [O] in which the channels are unganged
and each input channel can be routed to either or both
of the output channels.
- Stereo [S] ganging in which the Channel 1 fader
controls the gain of both channels and a stereo balance
control on the side panel comes into play.
If required, a factory modification allows the CH2
fader to control the relative level of CH2 so that
equality of level is achieved with the CH2 fader at
maximum. This can be useful as an MS width control when
handling MS without decoding.
- Mid-Side [MAT] ganging in which the Channel 1
fader controls the gain of both channels and the
Channel 2 fader acts as an image width control. The
incoming signal is assumed to be in MS format and is
matrixed to AB. The stereo balance control remains
active and will balance the matrixed signal.
|
| Phase Switch |
A front panel switch inverts CH2 phase.
This also interchanges left and right in an MS encoded
signal. |
| Channel 3 |
CH3 can be routed to LEFT, RIGHT or to a
PANpot. |
| Channels 4 & 5 |
Each of CH4 and CH5 can be routed to LEFT,
RIGHT or CENTRE (both). |
 |
Monitor Return Inputs
|
Two sets of monitor return inputs are provided
EX1 on a combined 12-Way connector[A]:
Balanced inputs with a range of sensitivity from -20dBu
to +20dBu for loudness parity with the internal
monitoring. EX2 on a 3.5mm jack [EX2]:
Unbalanced inputs of similar sensitivity.
The sensitivity is adjusted by a screwdriver preset on
the base, with an internal range switch.
|
| Mixing Bus Inputs |
The SUBSIDIARY I/O connector [B] carries
two inputs directly into the summing amplifiers.
Sensitivity is 0dBu for +8dBu at the balanced outputs with
the master gain set at 0 and can be trimmed
internally. |
| Balanced Outputs |
Two pairs of line drivers are
provided.
The No.1 outputs are available on a combined 12-Way connector [A] and the No.2
outputs on a 5-Way XLR connector. |
| Line Drivers |
The line drivers are electronically
balanced sources with a clipping level of +22dBm into 600
Ohms. Distortion at the nominal peak level of +8dBm is less
than 0.01% with a 600 Ohm load 20Hz to 20kHz. Output
resistance is below 10 Ohms and it is permissible to
forcibly unbalance any of the outputs without it affecting
the others. |
| Output Attenuators |
Switches on the base allow attenuation by
50dB at either set of connectors for microphone level
feed. |
| Unbalanced Outputs |
Two stereo 3.5mm jacks, UB and UB2 carry 220 Ohm
unbalanced outputs at 6dB below the main outputs, while
the 3.5mm jack UBM carries Mic-Level signals at 50dB
below the main outputs.
The SUBSIDIARY I/O
connector [B] shares the UB2 220 Ohm unbalanced
output.
|
Direct Outputs,
All Channels |
The SUBSIDIARY I/O connector [B] carries the five
unbalanced, pre-fader mic preamp outputs at a nominal
level of -10dBu peak from a 220 Ohm source resistance.
If a link to ground is made on the connector,
post-fader outputs are available instead. If a further
link is made, CH4 and CH5 are removed from the mix and
the signal routing for CH3 is changed so that selecting
PAN for CH3 will switch the channel out of the mix.
A presettable line-up tone for aligning external
recorders is provided, ganged with the main tone. Its
level of -10dBu corresponds to the preamp output with the
fader at 5 and peak level at the mixer output. The output
level (and tone) may be attenuated by 6dB using internal
switches.
|
| Meters |
Twin peak reading, logarithmic level
meters with Peak Programme Meter (PPM) dynamics. Scaling
may be BBC PPM, Nordic Norm, or
SMPTE.
VU meters can also be provided. The meters are
normally calibrated with the mixer driving a bridging load
of 10k Ohms. While the mixer is operating the meters are
illuminated by low power light emitting diodes. |
Line Output
Level |
The nominal line level is normally set at
0dBu for PPM metered mixers and +4dBu for VU metered
mixers. Peak level, which is used as a reference for the
limiters, is considered to be 8dB above this setting. Other
calibration levels are readily available to order. |
 |
| Output
Limiters |
[O]ff [M]ono [S]tereo (ganged) Attack time
constant 0.5ms, release time 100ms. The limiter range is
20dB. An LED for each output channel indicates limiter
action. This Graph shows the
entry into limiting on a steady signal for a nominal peak
level of 8dBu |
| Line-up Tone |
The Line-up tone is a sine wave at 1kHz
with distortion below 0.1% which is inserted into both
channels, displacing the audio output. When the
[GANG 1-2] switch is in either of the ganged
positions, the left hand channel tone is interrupted for
250ms every 3s. The tone switch on the front panel is a
three position toggle, shared with the Slating
Microphone. |
| Monitoring |
The mixer has a pair of headphone
amplifiers with adjustable gain. The outputs are available
on both quarter inch and 3.5mm jacks and are capable of
driving most types of headphone to a suitable level.
Pre-Fade listening to four of the input channels is
possible as is MS matrixing of the two output channels so
that an MS recording may be monitored in the equivalent AB
stereo. The headphone gain control is a tall knurled knob
easily accessible at the front of the left side panel. |
Monitoring
Mode Selector |
The monitoring mode rotary selector switch on the front
panel [PHONES] has the following functions.
- S Stereo
- R Right Channel
- L Left Channel
- MS MS Matrix (MS heard as AB stereo)
- L-R Left minus Right (MS stereo equivalent
Right)
- L+R Left plus Right
(MS stereo equivalent Left or Phase Check)
|
| Monitoring Source Selector |
A front panel toggle switch selects the
monitoring source as either internal [MXR] or
external [AUX] |
| Pre-Fade Listen |
A pair of front panel toggle switches
selects Pre-Fade Listen for channels 2 or 3 and 4 or 5. The
switches are three position, centre off. |
 |
| Slating Microphone |
A microphone is mounted behind the front
panel near the centre of the mixer. When in use, the output
of the microphone is levelled by a compressor and displaces
the normal audio, appearing on the mixer outputs and in the
monitoring system. While the microphone is active, the
monitoring mode automatically reverts to the internal or
[MXR] setting. The Slating Microphone switch on the front
panel is a three position toggle, shared with the Line-up
tone. |
| Batteries |
Eight AA size cells housed in a
quick-change compartment. The acceptable range of voltages
is 6 to 24 Vdc allowing the use of most cell
technologies. |
| Battery Drain |
135mA at 12 Vdc with unpowered mics.
Battery life with alkaline cells will be about 10
hours. |
| Battery Test |
The right channel meter is fitted with a
suppressed-zero battery voltage scale, brought into
operation by a front panel push button. |
External
Power |
A supply in the range 6 to 24 Vdc may be
used. The maximum consumption will be 2.5W and quiescent
consumption, without microphones, 1.6W. The input terminals
float with respect to ground. Either (or neither) side may
be grounded at will, thereby allowing the use of floating
supplies or grounded supplies of either polarity. There
will be no possibility of hum-loops being formed. |
| Power Distribution |
The mixer carries two four-way connectors,
one of which [DC] gives access to the internal batteries
for charging and also serves to connect to an external
power source. The second connector [PT] is an output which
provides a switched, short circuit proof connection to the
power supplied to [DC]. This allows the mixer to be used as
the focal point for a system of interconnected devices, all
controlled from the mixer’s power switch. |
| Temperature Range |
The mixer is designed to work over the
temperature range of -20 to +60 °C. |
| Dimensions |
The dimensions of the mixer case are:
Height 47mm, Width 297mm, Depth 161mm |
| Construction |
The outer case of the mixer is made of aluminium. The end
blocks holding the connectors and the panpots are milled
from solid aluminium bar. Inside the mixer is an inner
compartment of steel, tin-plated after forming, which
contains all of the circuitry that might be sensitive to
radio frequency interference. The top and bottom of this
compartment are sealed by copper screens and rf gasket
material and all inputs to and outputs from this
compartment are filtered. The circuitry is constructed on
multi-layer printed circuit boards with internal ground
and power planes which ensure the integrity of the
internal grounding system.
All control knobs are special to SQN and are turned
and milled from solid aluminium bar. The internal battery
compartment is milled and bored from a solid block of
polyacetal engineering plastics material and the moving
parts are aluminium and stainless steel.
All labels and legends on the mixer are permanent. On
the end blocks they are engraved; on the front panel they
are printed into the hard-anodised surface; on the
baseplate they are reverse printed on a polycarbonate
label.
The mechanical construction is a development of a
system which has proven in the past to be resistant to
mechanical damage.
|
| Weight |
The weight of the mixer without batteries
is 2.1kg |