Hornby Large Prairie sound, light and stay alive

[Harlequin]

Here's a quick look at how I have installed an MX645 with two speakers, firebox glow and stay alive in my Hornby Large Prairie.

 

I measured inside the body and worked out there was space to mount the decoder above the gearbox, effectively in the firebox. (This may not be the best place but more of that later.)

 

I removed the 8-pin decoder socket and cut down the plastic moulding that held it. I also removed the coal bunker floor because I wanted the entire bunker/tank space to hold a big speaker and a stay alive supercap.

 

The decoder sleeve was removed and replaced by Kapton tape to make it a bit thinner, then the decoder was hardwired to the pickups and motor leads (which are correctly colour coded by Hornby).

 

A firebox glow orange LED was encased in a small blob of copydex to insulate it from the metal body weight and fixed in place using tackyblack. Wires for speakers and supercap routed around the firebox LED and into the channel provided by Hornby.

 

The front weight was cut down and a YouChoos sugarcube speaker installed directly under the chimney.

 

With all the wiring packaged using more tackyblack and masking tape the chassis looks like this:

You can see the green sugarcube speaker up front and the big Zimo Dumbo speaker sitting on top of the supercap at the back.

 

On the test track everything worked so it was time to put the body on. I milled out a hole roughly where the firebox door should be, cleaned up and slid the body on.

 

 

My measurements were correct - the screws pulled tight with no feeling of anything being stressed! (Phew!)

 

Next to fit the coal load, which is also a speaker grille: A small piece of insect mesh was cut to size and shaped to allow the coal to sink towards the cab. I protected the electrical connection to the speaker with Kapton tape before pushing the mesh into place and gluing on coarse loco coal with copydex.

 

I've synced up the chuff rate and she looks and sounds very convincing on the test track. The only possible downside, which I accepted early on, is that the decoder doesn't have much cooling and so the top of the firebox gets quite warm. I know the decoder will automatically shut down if it gets too hot but so far so good - she's done many circuits without any signs of problems.

 

Videos to follow...

Edited November 29, 2020 by Harlequin

[Harlequin]

Not the best video in the world...

 

 

[Neal Ball]

This sounds great Phil. 
 

I wonder how much of a difference that sugarcane speaker makes.... it would be interesting to compare mine and yours together. The miles makes that a bit tricky!

[Harlequin]

7 hours ago, Neal Ball said:

This sounds great Phil. 
 

I wonder how much of a difference that sugarcane speaker makes.... it would be interesting to compare mine and yours together. The miles makes that a bit tricky!

Thanks Neal,

 

(You should copyright the "sugarcane speaker" as fast as possible before someone else uses it!)

  

 

I am striving to get as good sound as possible from my steam locos. A wimpy lo-fi plastic-box chuffing sound isn't enough.

 

I think the sound quality comes largely from the Zimo Dumbo in the bunker, with the sound allowed to escape more directly rather than bouncing off the track in different directions. I think the sugarcube mainly just adds volume but it also pulls the sound balance forwards, which is useful.

 

I reckon that the most important thing for good sound is the biggest speaker you can fit with a decent enclosure volume and it has to be matched to the decoder's amp output both in Ohms and power. If you have that sorted the next most important thing is a decent sound project because it doesn't matter how good the speaker is if the sound samples are poor quality...

 

It's almost impossible to compare sounds at a distance because there are so many variables involved. Probably the only foolproof way would be to exchange locos.

 

Edited November 29, 2020 by Harlequin

[Piemanlarger]

On 29/11/2020 at 00:23, Harlequin said:

Not the best video in the world...

 

 

 

 

What sound project is this please?

[Harlequin]

8 minutes ago, Piemanlarger said:

 

 

What sound project is this please?

YouChoos "All Prairies":

https://www.youchoos.co.uk/Index-Shop.php?L1=Project&Item=GWRPrairie