Bachmann's LNWR Improved Precedent is very simple to convert to DCC Sound, as it already has a SugarCube-style speaker on
board. A 21pin sound decoder (MX644D or MX644C for example) simply plugs in and off you go.
With the Zimo sound decoder, you may find that you need to tune the BackEMF settings for the coreless motor... we found
CV#56=22 to be a good option, giving good smooth control.
We used our LNWR Webb Coal Tank sound profile.
The factory-fit cube speaker is hidden under the PCB - it is a fairly low-power 15x11mm component, and is pretty quiet, but it
does make the conversion to sound simple, as long as you don't want too much volume.
Kit: MX644D; SugarCube7; SACC16 + 4x 470uF Tall Tantalums
The tender is really very short on space, so options for better kit are limited. However, we did find space along the side
walls for some Tantalum capacitors, in this case joined to a SACC16 connection kit (LifeLink would also work).
We also managed to create just enough space for a SugarCube7 speaker, which is joined in parallel with the factory speaker to
improve the overall sound considerably. The extra speaker needed to be covered in Kapton tape so it doesn't short-circuit on
Kit: MX644D; Dual SugarCube24X15X06; SACC16 + 5x 470uF Tall Tantalums
Our next example removes the weedy factory-fit speaker and puts in a dual SugarCube24X15X06 instead. Some additional work is
requried to create more space for this, and we were a little disappointed that only a 6mm high speaker would fit, but still, it
is overall an improvements, so worthwhile.
We also added an extra Tantalum, bringing it to 5x 470uF - a decent backup in this model.
Here are a few shots of 2 examples...