Athearn SD40 and MRC 1634 sound decoder


C

CP6027

Member
I installed a MRC 1634 sound decoder into a Athearn SD40. This is basically the same install as I did with a Tsunami and a RTR AC4400. The step by step is very similar to this thread Tsunami and a RTR AC4400

The difference is that I removed the rear weight and screwed a piece of sheet metal in it's place. This provides a place to mount a mini oval speaker facing up. This shell has the see through top fans that are perfect for letting the sound out.

Here is a video of the SD40 running on YouTube.

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Neat work and installation. I'm interested in your impression of that oval speaker too. If it sounds good, it would solve some space problems.
 
jbaakko said:
Nice work, pretty clean install too. How do those oval speakers sound?
Click to expand...

I think they sound great. Your limited in how much bass you can have with a speaker that small. I consider it in scale sound as deep sub woofer bass would seem wrong for such a small model. There is a link to a YouTube video of the SD40 in action running around my Atlas True-Track temp layout so you can see how it sounds. I'm always looking for a way to put a larger speaker in but there is usually just no room.

Jerry
 
Does removing the rear weight impact performance? I have several Athearn RTR SD45's that I want to upgrade for sound. I've read about several options: installing the speaker in the nose or cab; grinding the rear weight to fit an upward facing speaker; or buying an ultra-thin speaker for fitting on the rear weight.
Has anyone successfully installed DCC sound without removing the rear weight?
 
I installed a similar setup in an SD40-2 and SD45, and I had to remove the weight. I've found that by removing the weight, the leading truck (if long hood forward) will find any and every track problem I have (including ones I didn't know I had). I don't know how the original poster's results have been, but I've stopped putting sound in my SDs until I figure out how to either improve my track work or add weight to the locomotive.
 
ICG/SOU said:
I installed a similar setup in an SD40-2 and SD45, and I had to remove the weight. I've found that by removing the weight, the leading truck (if long hood forward) will find any and every track problem I have (including ones I didn't know I had). I don't know how the original poster's results have been, but I've stopped putting sound in my SDs until I figure out how to either improve my track work or add weight to the locomotive.
Click to expand...

I hear your pain. I went through alot of trouble trying to get sound installed in these Athearn models, now I'm sticking with factory installed DCC & Sound locos only.

"DCC ready" my A$$... LOL
 
As shown below, using CP6027's method and custom-fitting some lead weights might just do the trick without having to grind-fit the stock rear weight, i.e., steel plate, then thin slab of lead under the speaker as well as at the rear of the speaker. It might not be the same weight as the original rear weight but it would be very close.

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