Sutton's Locomotive Workshop British Railways Sulzer Type 2 Operating Manual - page 17
10. Digital sound operation
Introduction
Installing sound into a model locomotive significantly increases its cost. We believe
it should, correspondingly, increase its value. In our experience, too many sound-
fitted models fall well short of this expectation. We understand the frustration many
experience using restricted operational features usually provided with sound-fitted
models so we were determined to give you the freedom and the tools to decide how
your model’s movement and sounds interact.
We set ourselves the challenge of providing the ‘best ever’ sounding Class 24
model, incorporating as much user-control as possible. In both these regards we
believed our aim has been achieved, thanks to cutting-edge technology and the most
up-to-date recording methods and equipment. This model is notable for being the
first ready-to-run diesel to be factory-fitted with Austrian-made, high-performance,
DCC decoders from ZIMO Elektronik.
Close co-operation with ZIMO’s development team in Vienna has provided new or
enhanced control features ideally suited to British diesel operations. Our understanding
of the prototype and the software has enabled us to provide you with a sound project
able to simulate all normal operational sound and movement combinations. This
installation allows more realistic sounds to be deployed across a wider range of
operating conditions. The sounds have been programmed in such a way that you,
the user, may change the way that the sounds respond to your driving style or needs.
This avoids the need for reprogramming and additional costs that would imply.
The sound output of this model was judged to be the most authentic in a audio test,
which included a number of enthusiasts and professional railwaymen. Credit for this
must go to Paul Chetter, who is widely regarded as the leading authority on ZIMO
programming. Thanks to unprecedented recording access, his skill, enthusiasm and
attention to detail have created an exclusive sound project that will satisfy the most
ardent ‘Baby Sulzer’ fanatic. The distinctive ‘spluttering’ exhaust notes of the Sulzer
power unit have been faithfully recreated and will be instantly recognisable.
A truly successful project is one that captures the essential characteristics of the
locomotive. This includes how the model responds to control inputs, the relationship
between track speed and engine sounds, the balance of individual sounds within the
mix and how the installation affects the final results.
Please spend a few moments to read these notes which have been produced so that
you may obtain the maximum satisfaction from this revolutionary ZIMO sound
scheme. Some of the new features will not operate to their full potential if you use 14/28
speed steps. If at all possible, please ensure you use 128 speed steps to take maximum
advantage of these controls. Individual locos may require some fine tuning that you can
achieve with your DCC controller.
Sound specification
The model is fitted with a ZIMO MX645 PluX22e DCC sound decoder, tuned to a
pair of high-end miniature 8Ω loudspeakers housed in custom-designed plastic
enclosures mounted within the die-cast chassis. This arrangement was devised to
provide the best possible audio experience from the restricted space inside the
model. The decoder is also connected to a pair of energy storage capacitors.
The MX645 is a technologically-advanced chip, which is highly regarded because
of its impressive specification that includes a 40kHz ‘silent’ drive with back-EMF
sampling. Despite its relatively small size, it packs an incredibly powerful 3W audio
amplifier and an accommodating 1.2A continuous (2.5A peak) current rating. All
features, including up to ten function outputs, switch input and SUSI connections
are available for customisation. This model is configured to run ‘straight from the
box’ with ZIMO’s legendary silky-smooth motor control.
Our loudspeakers were originally designed for portable consumer devices, such as
smartphones and tablet computers where high quality sound is required but physical
space is constrained. It is the world’s first miniature speaker featuring advanced silicon
membrane technology optimised for extended low frequencies. The result is superior
bass performance over that expected from such a small device.
Premium ZIMO decoders have special on-board circuitry, described as an ‘electronic
flywheel’, to manage capacitors used as external power supplies. These are the stay alive
energy storage capacitors already included on the model’s PCB (or the replacement
SC68 supercapacitor upgrade). Once the decoder is attached, via the PluX connection,
it does all the charging and monitoring automatically.
ZIMO’s ‘Smart Stop’ system is unique and highly sophisticated. It is designed to avoid
stopping on an electrically ‘dead’ spot. As the loco is slowing down, just before it stops
completely, the decoder monitors the availability of power from the track. If it detects
poor supply - a speck of dirt for example - it prevents a final stop. Instead it keeps the loco
moving at minimal speed, using power from the connected capacitors if necessary. The
track conditions are continuously assessed and as soon as favourable power conditions
return, the decoder will stop the loco. The capacitors will be recharged during the
dormant period ready to supply power again when required. These movements are
very small and the monitoring so frequent that under normal operation it is almost
impossible to see it happening. However, it has the potential to transform running
characteristics and provide reliable starting in less than perfect conditions.
The system should not be regarded as an alternative to good permanent way
cleaning and maintenance, but it can be a real help if the wheels are not entirely clean
or the trackwork is uneven. The circuit assists in preventing unscheduled stops, sound
interruption and flickering lights. It can make the difference between successfully
crossing a dead frog or stalling on the points.
SLW Class 24 Operating Manual
Page 33
Page 32
SLW Class 24 Operating Manual