Wickness Models, 6 Greenlea Crescent, Collin, DG1 4PR    douglas@wicknessmodels.co.uk

DCC Sound and testing advice

Advice On Installing and Testing Sound Decoders

There are many ways to fit a sound decoder to a locomotive so it depends how you see it to some extent, in most cases it is relatively straightforward to either hard wire or plug in and locate the decoder but the speaker location can present problems.

The beauty of using sugarcube speakers is that they are easy to locate and happy to produce sound levels when exposed or when located in a tender with a vent for example. The attached baffle makes this possible. Standard speakers are also very good but usually larger and a little harder to locate, one tip for obtaining maximum sound levels with these is to use black tack (or any tack) to fill the little voids where the speaker baffle joins the drive unit (there are 6 in a standard ESU speaker), this will increase sound volumes dramatically.

Sugarcube speakers will produce good sound levels whether located in an enclosed space or exposed on the floor of a cab for instance. For all kinds of speakers make sure to locate the speaker with the drive unit (metal part) facing up if on the floor or down if stuck to an upper roof with black tack and ensure no live chassis parts can come into contact with the speaker terminals as this will cause a short damaging the sound circuits on the decoder. Also be sure that any loose function wires not in use are isolated with tape or heat shrink as a short through one of these will damage the decoder. It is in fact possible to wrap the whole speaker with kapton tape to prevent shorting and there is little or no reduction in sound depth and quality as a result.

The baffle on any speaker can also be removed and filed down to make a fit if necessary with little loss in sound quality, just file it to the size required and re-attach to the drive unit with a few spots of superglue.

There are a couple of things we recommend to test sound installations:

Firstly use a controller with a dedicated low current programming track so that when an installation is complete you can test it by putting the loco on the programming track, and reading back the decoder address or any other CV setting. This ensures that if there is a short anywhere in the installation no damage can be done because you have tested it in a limited current or low current environment. To explain this more fully, if you can communicate with the decoder all is good, if not, or if a short circuit error is reported on the controller there is a problem with the installation. You can then remove the loco from the track and trace the problem safe in the knowledge that no damage has occurred as a result of the test before exposing your hard work to full power on the main line.

Secondly, decoders themselves can also be tested prior to installation using a decoder tester connected to a dedicated programming track circuit on a suitable controller. By connecting the decoder to a decoder tester like the one we offer here you can establish that any sound decoder is fully functional before tackling a time consuming conversion.

On a final note concerning expense and risk, we recognise that sound decoders offering a genuine range of functions and realistic sounds for specific locos are an expensive investment. If disaster strikes we will replace any damaged Zimo MX range decoder at a cost of £30 including postage. The damaged one is sent for repair by us and we put it back in to stock when it returns from the manufacturer, meantime you get an immediate replacement (subject to current stocks of course). For ESU decoders replacement is at ESU’s discretion, they will replace any sound decoder which has no visible short circuit damage (i.e. scorching), free of charge but may levy a cost if there are signs of obvious short circuit damage.

Have fun and enjoy your sound installations, it can be very rewarding!

Douglas
Wickness Models

Wickness Soundscape Decoders on Loksound can be purchased here for all gauges

Zimo Sound Decoders with Youchoos soundtracks (60 steam, 30 diesel) can be purchased for all gauges here