Adding Sound to a Diesel Locomotive

[jonathan]

Folks,

We get a number of threads inquiring about adding sound to locomotives.  So, I'm sharing this sound project in hopes that it's helpful to those who are looking to add sound to their locomotives.

This is a Bachmann F-7A which happens to be DCC ready.  A non-DCC-ready locomotive would require a bit more soldering, but the principle is the same.  I already have a standard motion decoder installed.  Just have to unplug the old decoder:

DSC_1472 by Jon Vogel, on Flickr

I am working a train show this weekend.  While taking a break to shop, I happened across some bargain prices on the necessary parts for this project.

The Soundtraxx Tsunami TSU-1000 for EMD diesels is an early generation product, but perfectly fine:

DSC_1454 by Jon Vogel, on Flickr

This decoder puts out less wattage to the speaker than the newer generation decoders... So I can also get away with using the less powerful speaker.  The newer Soundtraxx decoders are more powerful and require their more robust speaker.  

For this project, I need a 28mm, 8 ohm speaker:

DSC_1457 by Jon Vogel, on Flickr

To save myself a little extra soldering, I also picked up an adapter, to make it easier to connect the decoder to the DCC-ready connector in the locomotive:

DSC_1459 by Jon Vogel, on Flickr

Less than 100 bucks to add sound is pretty good these days.

Now the work begins.  I started by carefully cutting back some of the shrink wrap on the decoder, to expose the spot where I will install the adapter plug:

DSC_1460 by Jon Vogel, on Flickr

This was done, gently, with the blade of Exact Zero (Exact-0 knife).

I used my thumb nail to gently wedge-out the existing plug:

DSC_1461 by Jon Vogel, on Flickr

Adapter plug installed:

DSC_1464 by Jon Vogel, on Flickr

Now to connect the speaker to the decoder.  There are two purple wires for the speaker.  Polarity (+/-) does not matter, since I am using only one speaker.  Here's the little bit of soldering required.  Stripped the wire and tinned the the ends:

DSC_1465 by Jon Vogel, on Flickr

The speaker is already prepped. It has two solder blobs at the connecting points.  This is convenient.  Only takes a second or two to connect the wires.  You don't want to spend a lot of time with heat applied to the speaker:

DSC_1469 by Jon Vogel, on Flickr

Now the electronics are prepped and ready to be installed in the loco.  I start by laying everything out, in position, just to get a feel for how much room is needed to make it all fit:

DSC_1473 by Jon Vogel, on Flickr

I forgot to mention earlier... In the above picture you can see a bit of tape I applied on two wire ends.  These wires are for extra functions:  flashy lights, smoke, whatever.  I won't be using the extra function, and I don't want any bare wires floating around, so I taped 'em.

Now that I've pondered for a while, I think turning the decoder around to face the other direction will save some room and make it easier to rout wires:

DSC_1474 by Jon Vogel, on Flickr

Now that I have a plan, I can mount the speaker.  I'll to work on that tomorrow.  Gotta head back up to the train show.  AND I can't seem to locate my silicone gel at the moment.  

More later...

Regards,

Jonathan

[jonathan]

To continue...

I use silicone gel (fancy caulk) to attach speakers.  Squeeze some out on to a paint stick:

DSC_1475 by Jon Vogel, on Flickr

Then use a toothpick to apply silicone to the speaker mount.  One can also apply some silicone to the speaker rim, BUT be very, very careful not to get any goo on the speaker itself.  I want to get the speaker applied quickly, before the gel starts to set up.  I didn't stop to shoot the gel after application.  Here is the speaker, gently laid on the speaker mount:

DSC_1476 by Jon Vogel, on Flickr

I left it to dry over night.  Felt nice and secure the next morning.

Now it's time to start configuring the wires and decoder as neatly as possible.  The speaker wires fit nicely between the frame and the PCB:

DSC_1478 by Jon Vogel, on Flickr

I had to change and rearrange the decoder a bit.  I mounted the decoder smooth-side-up/bumpy-side-down.  It sits the way it does because the shell needs to fit back down comfortably, without being forced.

In these shots you can see how I set it. Notice the capacitor position, and how those extra-function wires are nested away from the PCB, just in case:

DSC_1479 by Jon Vogel, on Flickr

The tape only serves to make sure the decoder stays in position while I secure the shell:

DSC_1481 by Jon Vogel, on Flickr

Now to find out if all went well. For programming, I use a SPROG II which connects the programming track to an old laptop.  I use a laptop to make the whole shebang portable.  Can take it to the club, train shows, where ever...

DSC_1482 by Jon Vogel, on Flickr

DSC_1487 by Jon Vogel, on Flickr

I have a tough time running the JMRI/Decoder Pro software...  Just not too user friendly in my opinion.  Eventually, I got it figured out.  I was ultimately able to to get the address programmed.  

The software also has a test throttle, so I can make sure the loco runs and makes sounds.  

I may, or may not have to speed match this loco with my other F units, which have decoders but not sound.  Maybe I'll get lucky, and they'll work nicely together without too much trouble.

Project finished for now.

Regards,

Jonathan

[Trainman203]

I may try this one day.  But I can't seem to manipulate a blob of solder less than 1/4 in dia.  I can get someone to do the install for me for $50.  Better to spend 50 than ruin $100 worth of stuff.

[WoundedBear]

Excellent tutorial Jon. Bachmann administrators need to sticky some of these how-to threads into a special folder.

Sid

[Trainman203]

Yes Jon it was great. The problem is that I am "chicken "🐓🐓🐓

[Trainman203]

I thought the purple thing was the decoder.  What's the green circuit board type thing?

[Len]

I thought the purple thing was the decoder.  What's the green circuit board type thing?

The green PCB is the OEM "mother board", with the 8-pin DCC socket on it. The purple thing is the new sound decoder that replaced the original black shrink wrapped motor decoder.

Len

[dutchbuilder]

Come on guys this one is easy.
Just plug and pray.
Try to install a decoder without connector and all black wires.
That's challenging.

Ton

[jonathan]

First, thanks, guys for the kind words!

Second, yes. This was an easy one.  I intentionally picked a less difficult sound project. Hoping this will be helpful to those who are thinking about doing a sound project, but may be intimidated by the complexity.

I could have picked one of my brass steam locos, with no speaker holes, much less any wires. I felt that would be very intimidating albeit impressive. There's someone in my club who lives for that sort of thing. I don't like to work that hard.

If you look back far enough on this board, I remember a couple of members having posted some pointers on difficult DCC projects, requiring frame grinding, wire hunting, and the like. Very cool stuff.

Regards,

Jonathan