Scale Trains Dash 9 Sound Upgrades [Benson Locomotive Works]

[kiwi_bnsf]

The C44-9W was the latest and greatest on the BNSF in my 1999 era, and was being delivered in numbers (but thankfully hadn't yet displaced all the interesting older power).

I have ATSF, BNSF, UP, SP and NS Dash 9s on my roster. I'm a huge fan of the Scale Trains Dash 9 — Scale Trains have relieved my wallet of a lot of cash (all my Kato units have been sold — they can't compete with the level of detail, nor the accuracy of details like ditch light locations, handrail styles, steps, aircon units, grilles, fuel tank air tank detail etc etc).

With my recent New Adventures in Loco Hi-Fi (https://www.therailwire.net/forum/index.php?topic=55532.0) I turned my attention to the Scale Trains Dash 9 to see if the running quality and sound could be improved.

In terms of chassis design, there is not much free space to spare. I ended up cutting off a chunk of the upper frame in order to sneak in an Iowa Scaled Engineering Power Keep keep alive between the rear drive shaft and the decoder. This only adds 940 microFarads of capacitance, but makes a huge difference to the reliability of the sound. The ground and +12V connections for the keep alive are located on the upper side of the ESU Loksound V5 Next18 board itself (please excuse my terrible soldering)…

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With the right orientation of the keep alive and careful application of kapton tape, you can wedge everything in and just clear the drive shaft. The clearance of the drive shaft is very tight, so it may be necessary to shim it a bit with 0.25mm styrene (I will try one of the TCS KA-N1 keep alives for my next install, as this has a smaller footprint).

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As an aside, the resistor and diode configuration on the Iowa Scaled Engineering Power Keepers means firmware and sound files can be loaded onto the ESU decoder without having to disconnect the keep alive.


Next up was the speaker. The stock speaker is actually quite decent — an 11x15mm unit with an integral chamber that is sealed with double-sided tape to the underside of the chassis. However, it sounds inferior to my own custom 3D printed "Benson Locomotive Works" speaker chambers that I've been testing with my Kato SD40-2s.

So with much gritting of teeth, I milled away as much of the fuel tank as I dared. I kept the two screw threads that attach the fuel tank, but I got rid of the motor mount screw holes entirely. This left the plastic motor mounts to deal with…

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This necessitated a speaker enclosure designed with integral motor mount holes. I stuck with the Ole Wolff 9x16mm speaker as this sounds good in my SD40-2. A smaller 9x16mm allows a fully enclosed chamber with a reasonable wall thickness for rigidity. Space is really tight, so I also included channels for routing the wires flush. The total internal volume of the chamber is only 850 cubic mm…

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Here's the finished enclosure installed. I'm really happy with the tolerances that are possible with the AnyCubic Photon Mono X 6K 3D printer. The screw mounts for the motor are nice and strong. The speaker is a press fit, and some thin CA seals it well…

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Here is a video comparison of the Scale Trains stock speaker vs the Benson Locomotive Works upgraded version (the sound file and settings are identical)…

     

Overall I'm really happy with this upgrade. Probably the most time consuming aspect is the disassembly and re-assembly steps. It is possible to do this with only re-soldering the wires to the speaker, but it does necessitate completely disassembling the trucks in order to be able to work with the bare frame. I took the opportunity to paint the outsides of the copper pickup strips black, and the wheel centers rust brown. I also carefully cleaned the axle holders and applied the tiniest amount of Peco conductive lube — performance seems a little better (although I still need to tweak the BEMF settings a bit more).

I think I'll be able to do the next Dash 9 in the queue in about 2-3 hours from start to finish 

I hope this inspires others to hack up their Scale Trains Dash 9s.

[tehachapifan]

Sound great!

I did my own custom installs on two of these as well, although not quite as in depth as yours.

What sound file is that and does it have that compressor as the default or did you import it? I imported that same compressor into mine, but it didn't trigger the high idle like the default compressor did.

[kiwi_bnsf]

Sound great!

I did my own custom installs on two of these as well, although not quite as in depth as yours.

What sound file is that and does it have that compressor as the default or did you import it? I imported that same compressor into mine, but it didn't trigger the high idle like the default compressor did.

You have a good ear — it's the stock Scale Trains sound file but with the compressor sound swapped out for a slightly better "whoop" compressor. To be honest, I'm still on the hunt for a better whoop compressor — none of the ESU sound files seem to capture it properly.

I hadn't realised that the stock Scale Trains compressor was tied to logic to change the idle — I will have to see if I can recreate that in the sound project.

[Dwight in Toronto]

Damn, the fit & finish of that speaker enclosure and it’s placement supercedes an OEM factory job, let alone the magnitude of sound quality improvement.   What an upgrade!

[Ed Kapuscinski]

If you need help with fitment of the keep alive, you might want to try using wires pulled from Cat 5 cable. I did that on my F40PH and it was pretty handy.

[peteski]

Nice compact install Al Tim!

If you need help with fitment of the keep alive, you might want to try using wires pulled from Cat 5 cable. I did that on my F40PH and it was pretty handy.

Wire from CAT5 cable? 
That is 24AWG (0.205mm²) usually solid, copper wire.  Thick and stiff!  Even if the conductor is stranded, it is still awfully bulky for any N scale DCC installs.

Judging by the colors, I believe Tim used the standard ESU decoder wire they use in their wired installs.  It is 30AWG (0.05mm²).  The diameter of the conductor is only 0.010", and the OD if the insulation is just 0.020" (which is about the same as just the CAT5s conductor's diameter).  The strands in ESU wire are very fine, making the wire super flexible.

[kiwi_bnsf]

Nice compact install Al!

Wire from CAT5 cable? 
That is 24AWG (0.205mm²) usually solid, copper wire.  Thick and stiff!  Even if the conductor is stranded, it is still awfully bulky for any N scale DCC installs.

Judging by the colors, I believe Al used the standard ESU decoder wire they use in their wired installs.  It is 30AWG (0.05mm²).  The diameter of the conductor is only 0.010", and the OD if the insulation is just 0.020" (which is about the same as just the CAT5s conductor's diameter).  The strands in ESU wire are very fine, making the wire super flexible.

You are correct — I used ESU decoder wire. I've found this to be very easy to work with (both in terms of soldering and bending).

Who is this Al you speak of? 

[MK]

He's confusing you with the other Kiwi.   

[peteski]

He's confusing you with the other Kiwi.   

I was!    Fixed!  Sorry!