Adding DCC Sound - Doubly Complicated?

[Stephen in Kerry]

I've decided that I am going DCC for my first every layout (based on Trackmat Extension 4 in the current Hornby Track Plans book.)

I'm getting close to ordering the track and will probably buy the locos separately, rather than starting with a 'set'. I'll therefore probably start with some DCC fitted and DCC ready locos, as I especially want to have an industrial section to the layout, including shunters similar to that driven by my father.

DCC is largely a mystery to me - as is much of railway modelling to be honest, and I've just downloaded Nigel Burkin's book 'Practical Introduction to Digital Command Control...' to my Kindle, to help throw some light on the subject for me.

What I'm not clear about - and something that isn't really explained in the Hornby catalogue - is whether DCC sound needs an additional decoder (I assume it does), and how complicated (or possible) it might be to fit 2 decoders in the same loco, especially smaller models.

Your advice is welcome.

[Rog RJ]

You only need the sound decoder. It does everything. Most sound decoders come without a speaker, so you will usually need to buy a speaker too.

TTS decoders come with a speaker but it's not very good and you might want to investigate alternatives.

[Stephen in Kerry]

UPDATED: @Rog(RJ) thank you for the quick and helpful reply. Much appreciated. However, another question it threw up for me was... if I buy a DCC fitted loco, will it always have sound?

And if not, is fitting two decoders in the same loco impossible?

Apologies in advance for the newbie questions.

[Rog RJ]

Unless it says sound fitted or similar, a DCC fitted loco will not have any sound capabilities. If you really want sound, replace the no sound decoder with a sound decoder and sell the removed decoder.

Hornby locos that have TTS fitted will have TTS as a suffix to the "R" number eg R3395TTS.

Older Hornby sound fitted models, which were made before TTS decoders came out, had XS as a suffix.

Basically, read model descriptions carefully.

[Stephen in Kerry]

@rog (RJ), thank you again - I'm learning a lot here!

[Going Spare]

You can't mix DC and DCC control systems on the layout unless they are totally isolated electrically from each other.

DCC-ready locos will not run on a DCC layout without a decoder being fitted and I think I am correct in saying that DCC-fitted locos will often not work on a DC layout.

[Stephen in Kerry]

@Going Spare there's nothing in either of my previous posts to suggest I intend to mix DC and DCC (I don't).

When I said I would use a mix of DCC fitted and DCC ready locos, I meant that I would fit decoders myself if not already fitted.

I'm really asking about whether I need 2 separate decoders in the same loco, when adding sound to a DCC loco.

[Lyd 85B]

As Rog says, ask the right questions about DCC when you buy any loco. More modern ones may be described as DCC Ready (it is fitted with a socket that can take a decoder), DCC On Board (it has a factory-fitted decoder - usually non-sound), or TTS (Hornby's own factory-fitted sound system). Older locos may be DCC Compatible but with no on-board socket (the decoder, or a socket, needs to be soldered into the loco), and Non-DCC Compatible, which usually applies to older split chassis models. The latter are capable of conversion, but it's a bit of a faff and not for the beginner. Learning about DCC has been very rewarding for me and I have done many conversions, but I'm always learning more.

[Stephen in Kerry]

@Lyd 85B, when I was teaching at university my motto was, knowing the right questions to ask is more important than having the answers. Your helpful post really backs up that idea.

[96RAF]

Correct Stephen. You may notice in many posts we spend a long time wrestling the real problem out of some posters by way of iterative questioning until we get to the root of the matter, whereupon we can advise accordingly.

[Bulleidboy]

Also remember a DCC Ready loco will have a blanking plate fitted into the socket. This needs to be removed before fitting the decoder of choice. Do keep to blanking plate - should you decide to take out the decoder it is best to refit the blanking plate immediately.

[Fishmanoz]

Answering the question is there ever any need to fit 2 decoders - No. You either fit a sound-capable decoder or non-sound, not both. Sound decoders have all the same capability to adjust, control and run locos as non-sound, plus they have sound.

[Stephen in Kerry]

@Fishmanoz, thanks for that very clear answer, I wish the Hornby catalogue was so easy to understand.

[ColinB]

This subject seems to come up time and time again. It is pretty difficult most of the time to find room in the loco for one decoder let alone two. Then we have the fact that there is only one socket. Usually the instructions that come with the loco, of late it tells you where to fit the DCC sound decoder or normal decoder.