SQN-4S
series 1V, Miniature 4:2 Sound Mixer with Portabrace shoulder bag that will
take a recorder and radio microphones, 12 pin Tajimi cable and Tajimi tail with
2 x XLR/M and 3.5 jack return.
The original broadcast quality stereo portable mixer for TV,
film and radio locations
The SQN-4S has been the unraveled Industry standard portable audio mixer since it was the first to arrive on the scene back in 1984.
The new SERIES IV is
the culmination of an extensive development program to ensure that the SQN-4S
remains at the forefront of location sound technology. Extending the control
panel to include all the required functions on one face of the mixer has made
it even easier to use than before.
Newly designed tranformerless
input amplifiers, larger output transformers for low distortion bass, virtually
unbreakable analogue level meters, pre-fade listening, slating microphone, logic
processing of many switching functions leading to a minimal length audio path,
optional feed for four output channels and improved filtering and screening
have all contributed to making it a welcome successor to its illustrious forbears.
The essential information
for connecting to and operating the mixer is permanently printed on the baseplate.
Features and Specification - SQN-4S Series IV
Mixer Inputs
Four transformerless balanced inputs using XLR-3 type female connectors. Channels
one and two also share an XLR-5 type connector.
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, -12dB or -24dB
Bass Cut:
Flat, -4dB or -10dB at 100Hz
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 24dB 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
[GANG]
[MAT]
The mixer is intended to work in several modes. The mode controls affect channel
pairs CH1 & 2 and CH3 & 4. Within the pairs, channels 1 & 3 are
called "first channels" and 2 & 4 "second channels".
Twin MONO [O] in which the channels are unganged and each input channel can
be routed or panpotted to either or both of the output channels.
Stereo [S] ganging in which the first channel fader controls the gain of both
channels and the first channel panpot acts as a stereo balance control
Mid-Side [MS] ganging in which the first channel fader controls the gain of
both channels and the second channel fader acts as an image width control.
Mid-Side Matrix [MAT] matrixing in which each channel pair has a mid-side matrix
which will convert an MS input into AB stereo or vice-versa.
Panning Mode [PAN]. The CH3, CH4 pair has a selectable panning mode in which
the output is treated as MS encoded stereo and the channel signal is panned
to move across the equivalent AB stereo image.
Phase Switch
The second channel of each pair can have its phase inverted by means of a front
panel switch. This has the incidental effect of interchanging left and right
in an MS encoded signal.
Monitor Return Input
Unbalanced inputs with a range of sensitivity from -20dBu to +20dBu for loudness
parity with the internal monitoring. The sensitivity is adjusted by a screwdriver
preset on the base.
Mixing Bus Inputs
Two inputs directly into the summing amplifiers with their gain adjustable inside
the mixer. Maximum sensitivity is 0dBu for +8dBu at the balanced outputs with
the master gain set at 0.
Balanced Outputs
Two line driver amplifiers provide the output channels and each output is available
on both an individual XLR and a combined 12-way connector.
Output Attenuators
The level at either set of connectors can be attenuated by 50dB to provide a
nominally microphone level feed.
Line Drivers
Floating sources (transformer coupled) with a clipping level of +20dBm into
600 Ohms. Distortion at the nominal peak level of +8dBm is less than 0.01% with
a 600 Ohm load 20Hz to 20kHz. The output resistance is switchable from 60 Ohms
to 180 Ohms. At 180 Ohms, with the limiter switched on, the mixer can be worked
into an arbitrarily low impedance load with acceptable distortion. The balanced
Mic-Level send is derived from a separate winding on the output transformer
and has an essentially resistive source impedance of 200 Ohms.
Unbalanced Outputs
A subsidiary connector carries separately buffered outputs at 10dB below the
level of the main line drivers.
Post-Fader Outputs,
CH3 & CH4
Buffered outputs at 10dB below the level of the main line drivers. Channels
three and four may also be switched out of the mixing bus so that they can be
recorded separately.
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. Meter illumination is by permanently
lit glow tubes which consume no electrical power.
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
Switchable [O]ff [M]ono [S]tereo (ganged). Approximately 40:1 compression over
a 17dB range. Attack time constant 0.5ms, release time 100ms. The limiter threshold
is set 1dB below the nominal peak level. An LED indicator for each output channel
shows when the limiter is attenuating the signal.
Line-up Tone
A tone at 1.05kHz which is injected into both channels upon operating a front
panel switch. Two modes are available, [M]ono in which the tone is injected
at a fixed level into both outputs and [S]tereo in which the left hand channel
tone is interrupted for 250ms every 3s. The tone displaces the normal channel
signal.
Monitoring
Headphone amplifiers with adjustable gain capable of driving most headphone
types to a suitable level. The use of headphones with a resistance of between
200 Ohms and 600 Ohms per side will make best use of battery power. The gain
control is on the connector side panel. Please note that with some sets of headphones
it will be possible to produce sound levels capable of damaging the hearing
if the phones gain is set too high. Pre-Fade listening to each 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.
Monitoring Mode Selector
The monitoring mode rotary selector switch on the front panel [PHONES] has the
following functions.
S Stereo
L Left Channel
R Right Channel
L+R Left plus Right
(MS stereo equivalent Left or Phase Check)
L-R Left minus Right (MS stereo equivalent Right)
MS MS Matrix (MS stereo equivalent)
Pre-Fade Listen on each Channel PF 1, PF 2, PF 3 & PF 4
Monitoring Source Selector
A front panel toggle switch selects the monitoring source as either internal
[MXR] or external [AUX]
Slating Microphone
A microphone mounted behind the front panel at the right hand end of the mixer
is brought into operation by pressing a button on the side panel. The output
of the microphone is levelled by a 2:1 compressor and overrides the main 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.
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
life with alkaline cells will be 10 hours when using unpowered microphones.
Battery Test
The right channel meter is fitted with a suppressed-zero scale, brought into
operation by a front panel push button, which indicates the battery voltage
directly.
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
Weight
The weight of the mixer without batteries is 2.2kg
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.
The SQN-4S series IV
mixer offers the professional recordist:
Unsurpassed sound quality
Industry standard acceptability
User friendly ergonomic layout
Tried and tested electronic design
Superior mechanical engineering
Lowest running costs
Highest resale value
Long trouble-free service
The utmost in portability
Efficient factory back-up service
To buy this item please telephone:
Mike Harris 01932 241948