Kit: MX660; SugarCurve6; SACC16 with 2x 330uF Tantalums; Cab lights; Drivers
This approach to fitting DCC Sound involves Zimo's MX660 PCB sound decoder. The main benefit is that we do not need to modify
the chassis at all, so we do not need to dismantle anything apart from the electrics.
In fact, the trickiest bit is rewiring the model's lights to work with the MX660. I prefer to remove the existing wires from
the lighting boards, and put on some fresh ones, using colours that make more sense in the DCC world (blue for common positive,
white for white lights and yellow for red lights). We also snip out the pickup screw holes from the original PCB to reuse.
The MX660 is a very thin, single-sided decoder, which we place on double-sided tape, which is on turn placed on electrical tape
- used generously to ensure that the decoder doesn't touch the chassis directly. Soldering the orange and grey wires direct to
the motor terminals is a little tricky, and requires a fine point-tipped iron, but everything else is easily accessible.
We use a low-profile YouChoos SugarCurve6 speaker, which sits at one end. We do have to file down a little of the underside of
the end roof fan, but not too excessive - remember this is an easy alternative to modifying the chassis! Of course, the speaker
is fully insulated underneath, as its' electrical contacts must not touch the chassis.
The lighting board wires attach directly to the various AUX pads around the edge of the MX660 - there is no need for resistors
since the MX660 provides its outputs as reduced voltage anyway, so that greatly simplifies the re-wiring. It has 6 AUX outputs,
so we can have headlights, tail lights (and optionally cab lights) all working independently and directionally.
Since the MX660 is so compact, we have ample room to add a small stay-alive too, which improves slow-running quite noticeably.
This is done using a SACC16 kit with 2x 330uF Tantalum capacitors.
In this example, we have also added our own cab lights, and stuck in drivers.
All fitted up, here is our green beast...
Here's another one with pretty much the same kit, done in the same way...
If you don't mind a little bit of grinding, then a much deeper SugarCurve speaker can be fitted without too much trouble. Here
we managed to get a SugarCurve9 in, as well as 3x 470uF Tall Tantalums with LifeLink for stay-alive. The extra depth of the
bigger speaker especially helps with the bassy Deltic sounds.