DCC sound into a double-header with dummy loco

[retroman]

Good morning,

 

I'm sure this has been asked before, I've done a search but nothing obvious appears.

 

I have a Bachmann Class 25 with a worn motor/driver train which requires complete renewal.  Rather than  do that, I was thinking of removing the innards of the old loco and buying another Class 25 with DCC sound, with the intention of running them as a permanent close-coupled pair with a loudspeaker in the dummy.

 

Is this possible?  If so how do I wire the second speaker to the chip?

 

Excuse the ignorance, I'm returning to the hobby after a five-year gap and DCC has always been something of a mystery to me.  Many thanks in anticipation.

[njee20]

You just need to wire the speaker to the decoder on the powered loco. Assuming a standard 8ohm impedance you’ll want two 8 or 16 ohm speakers if in parallel, or two 4 ohm if in series (I think...). Should be alright. I’d contemplated doing something similar myself. 

Edited June 6, 2020 by njee20

[retroman]

25 minutes ago, njee20 said:

You just need to wire the speaker to the decoder on the powered loco. Assuming a standard 8ohm impedance you’ll want two 8 or 16 ohm speakers if in parallel, or two 4 ohm if in series (I think...). Should be alright. I’d contemplated doing something similar myself. 

That's great.  Many thanks indeed

[retroman]

On 07/06/2020 at 10:32, Richard Croft said:

The easiest way would probably be to use two 8 ohm speakers in parallel through a plug and socket, then you could still use the powered one on its own if you wanted without the dummy connected.

 

Richard

Thanks Richard.  That sounds good (pardon the pun!).

[SRman]

I did this with a pair of Bachmann class 20s, with a 2-pin plug and socket arrangement going through the lowest centre headcode disc recess on one, and skirting the edges of the nose on the dummy unit. In my case the decoder is an older ESU v3.5, so I had to use two 100 ohm speakers in parallel: a small one in the powered diesel, and a much larger bass reflex one in the dummy one. If the plug comes adrift, the sound difference is quite dramatic, being rather tinnier and weaker (no room for anything better in the motored unit).

[43110andyb]

There are some very discreet sockets that can be fitted so if you do split the locos the motorised loco can still be used singularly. I have just fitted one to a class 20, pictured during installation.

[Mark Forrest]

I have also done this with a pair of 20s.  Initially I had motor and decoder in one loco, large speaker in the other, connected via a two pin plug/socket.

The pair were placed on the track without the speaker plugged in and that caused some damage to the (Zimo) decoder.  When I replaced the decoder I added a small "sugar cube" speaker in the loco with the motor to prevent the same thing happening again and so it could be used on its own if needed or connected up as a pair.

[newbryford]

If you do use a 2-pin connector between locos, make sure the socket is on the end/loco with the decoder.

It's not good having a plug on a lead from a decoder that may touch the rails...…..

[43110andyb]

Another pic of the completed duo! Live loco on the right with socket fitted and dummy left with flying lead to plug into its living mate!

[retroman]

On 09/06/2020 at 13:51, 43110andyb said:

Another pic of the completed duo! Live loco on the right with socket fitted and dummy left with flying lead to plug into its living mate!

That's a superb job, very neat!