Hi everyone.
A friend asked if I could install sound in his Walthers/LL DL-109. I said "sure" - but this turned out to be a lot more difficult than I had imagined.
As usual, I'll cut to the chase with a video of the completed project, using LokSound's dual 539T sound file. After the first prime mover starts up, you'll hear the second do it's startup at about the 20-second mark. Note that the shell has been stripped and readied for painting.
The installation problem with this engine is that there is literally NO space between the frame and the roof of the shell; none. So nothing can protrude above the original frame line. And on top of that, the frame itself doesn't have much excess height to mill off for locating the decoder and speaker.
After taking the engine apart, however, I determined that there were two areas on the frame where I could mill down about 4.5mm. One was about 38mm of length at the rear, which was enough for a wired LokSound Select Micro and a couple of keep-alive caps. The second was at the front - about 18mm of length. That was enough for a 9x16mm speaker with an enclosure made out of .030 styrene, but there was only about 4.5mm of depth - not enough to get me decent sound if I simply built the enclosure as a box around the speaker itself. So instead I turned to the same technique I used for making a speaker enclosure to replace the original factory speaker in my IM SD40-2. This enclosure is very thin (about 4.2mm, including the base), but I made it wider than the speaker itself to add more internal air volume. And this would work nicely once I milled out the front part of the frame.
So here are the installation pics.
This is the disassembled engine frame (BTW, there was white grease all over everywhere - I ended up cleaning everything in my ultrasonic cleaner to get the overflowing grease out!):
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You can see from this photo that there just isn't a whole lot of excess metal at the top of the frame to mill off - you'll hit the flywheel, driveshaft and/or worm gear bearing mounts in very short order. But there is just enough! Here is a photo of the milled frame:
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I milled off 4.5mm from the top-most part of the frame (it curves; my measurement was from the peak of the frame), 38mm of length in the back, and 17mm of length in the front.
I also milled a channel on each side of the frame to attach pickup wires to the phosphor-bronze pickup strips, and I milled a small channel the length of the frame on the outside left edge to stash wires for the speaker and the front headlight LED. Remember, you just can't have wires or anything else sticking up above the frame on this model. Here's a side view of the left side after milling:
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Now it was time to start wiring. First the motor, insulated with kapton tape after soldering the wires:
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Then the pickup wires to the phosphor-bronze pickup strips:
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Next came the speaker - you can see in this photo how thin the speaker enclosure is and note where I have the wires exiting the enclosure (the eagle-eyed among you may see a tiny hole in the top of the enclosure in the photo after this one; I originally had the wires exiting out the top of the enclosure, but that was a no-go due to the lack of clearance between the frame and shell in this loco; so I filled that hole with thick CA, and used a side exit for the wires):
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Here's a view from the top down, with the speaker and decoder in position:
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I saved the original light board, but replaced the horrid orange LED with a golden-white one (make sure to cut the traces so that your new LED doesn't get power from the frame), and used 32-gauge magnet wire to wire it up to the decoder. Then I stashed two 220uf keep alive caps in the very rear. Here's the final installation view (the free wire is the negative wire from the keep alive caps, which I hadn't yet soldered to the decoder):
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Doing this installation was just as challenging in some ways as the VO-1000 I did a few years ago. But it works, and I think those dual 539T prime movers sound wonderful. And BTW - in this sound file, the second prime mover is in sound slot 20. That means you can separately map the second prime mover to a function key and turn it on yourself if you'd like.
It will be interesting to see what Atlas does with this model, if they update the chassis for DCC/sound. Even though I milled off quite a bit, the thing still weighs a ton - there's a LOT of metal in this chassis. But if Atlas redesigns it for a drop-in ESU board, it will look a lot different!
John C.
