Example 1: Heljan O Gauge Class 55 Deltic (XL socket version) - speakers in the fuel tank

Kit: MS990L; 2x YLR603010

Like a number of Heljan's big diesels, the Deltic has been re-released with an XL-style decoder socket, which should in theory make it simple to fit DCC Sound... and it is pretty simple, but there are a couple of gotchas to be aware of...

There is plenty of space in the fuel tanks for your choice of speakers - we're not showing those here, as the point of this guide relates to the decoder socket.

On taking the body off, we see the XL blanking plate for DC running. In front you can see our Zimo MS990L that we intend to fit.

So, the issue is that the 'XL' standard is not quite as standard as you might hope. ESU's XL (which the model is designed for) provides a single row of pins for servo connection, whereas Zimo's implementation (which provides for more servos), has a 3-row arrangement. There are of course no servos in this model, or any of the Heljan models to date, so they are not required.

So, the first modification is to remove the unwanted servo header socket from the model... take a pair of grippy pliers and slide it up and off (make sure you pick the right header socket!). Once the plastic socket is off, you can simply snip the electrical pins that are releaved.

Our next problem is that there are more pins on each of the remaining 3 sides of the decoder than there are in the headers of the model. They are not required, but the problem is that if you simply push it down into the socket, the extra pins can make contact on the backs of the little white sockets and cause shorts when power is applied. So, once you identify which are the extra (not required) pins, these can be carefully snipped short, just enough that they do foul on anything in the model.

When this is all done, plug it into the model and you're ready to go!

We have a special version of our Deltic MS project with lighting pre-configured to support this model - there are lots of lights!

Example 2: Extra speakers in the body

Kit: MS990L; 2x YLR603010; YLR453520; YLR302815

Having a pair of YLR603010 in the fuel tank is pretty good, but we'd like even more - particularly more bass, and there is space in the body for a bit more. The YLR453520 speaker is key to this as it provides a good rumble.

Start with the same pair of YLR603010 in the fuel tank...

If we position our YLR302815 and YLR453520 carefully, we can fit these in without any modification. The MS990 has 2 speaker outputs, so we join a YLR603010 with the YLR302815 and the other YLR603010 with our YLR453520, each pair in parallel, so we end up with 4 ohm on each pair. The MS990 supports a massive 10W on each channel, so well within capabilities!

To make connection clearer, we solder the speaker pairs to the feet of the socket in the model. Some careful soldering required here, but it is quite accessible.

MS990L plugged in (after removing any unwanted pins that are off the ends of the sockets, and removing the header socket from the model on the side meant for servos).

Wow, what a sound!

Please note that these guides are provided as useful resources for you, as-is. YouChoos cannot be held responsible for errors in the information, or for any damage caused to your models or equipment if you choose to follow any of the steps detailed here.