# Digitraxx SDH166 Sound Decoder



## Hutch (Dec 19, 2012)

Just installed one this morning and I'm very pleased with what I got. It doesn't compare to a Soundtrax or anything high end but, for the money, I like it and will buy more of them in the future. When I get a little time I'll make a video. Right now, it's in my Mikado 2-8-2 but I plan to switch it out when I get my Soundtraxx decoder from NIMT. I'll then install it in my little 0-4-0 steamer.

I think it needs a place for the sound to come out and right now there isn't one. I was considering drilling some holes in the coal for the sound to come out. What do you think?


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## mopac (Feb 24, 2011)

I have 1 of those digitrax sound decoder but have not installed it in anything yet. Looking forward to doing so. Glad to hear it sounded ok. I have some tsunamis and
I don't expect it to sound like them but ok is ok. I might do digitrax for some of my diesels but will do tsunamis for my good steam engines. The digitrax is alot cheaper,
no matter what Sean says.

Oh, I would drill holes in bottom of tender.


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## golfermd (Apr 19, 2013)

If it sounds good to you that all that matters. Sounds like you have good one (no pun intended). I am not flush with a lot of excess cash either so saving money is always a consideration for me.


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## Hutch (Dec 19, 2012)

Here's the video.


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## golfermd (Apr 19, 2013)

Link says the video is private.


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## Hutch (Dec 19, 2012)

I fixed it.


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## NIMT (Jan 6, 2011)

mopac said:


> I have 1 of those digitrax sound decoder but have not installed it in anything yet. Looking forward to doing so. Glad to hear it sounded ok. I have some tsunamis and
> I don't expect it to sound like them but ok is ok. I might do digitrax for some of my diesels but will do tsunamis for my good steam engines. The digitrax is alot cheaper,
> no matter what Sean says.
> 
> Oh, I would drill holes in bottom of tender.


Digitrax is cheaper than Soundtraxx, that's very true.


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## Hutch (Dec 19, 2012)

There's really no place to let the sound out of the bottom on this one. Some previous owner in an attempt to get better pickup, put in a huge hunk of steal, 1/2" thick and it's epoxied in. A friend suggested I just cut a hole in the coal area and place a piece of screen. I think that will be the best way to get all the sound out. Maybe I can make it look like something, I don't know what. Holes or screen, I don't think it will have much effect on the look. Maybe I could sprinkle some fresh coal over the whole thing. Now that would look good.

Digitraxx is about $45.00 cheaper when all is said and done. Speaker and baffle is included. It's plenty good enough for the cheaper engines picked up at shows and such. Soundtrax will always go into the better equipment.


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## keymania (May 22, 2014)

*SDH166 chuff not loud*

I just installed the Digitrax SDH166 into a 4-6-2 pacific and can't get the chuff sound loud enough. I also have a 4-6-2 with SoundValue and is superior, and a 4-6-2 with Tsunami which is superb, but costly. I'll have to turn down the volume on the others to balance with the SDH166, but don't to do this.

I've pumped the CVs to max. 140, 58, 142, etc. The alternate crossing gate whistle F7 is barely heard and I can't find how to increase this CV.

I've just drilled holes in the tender which helps slightly. Next I'll move the speaker over the holes in the floor and test again. I have another tender I'll drill holes in the coal and try that. Anyone had experience with this problem?

I have another SDH166 installed in a diesel and is better.


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## D&J Railroad (Oct 4, 2013)

One of the important things with speaker systems is having a good enclosed sound box on the backside of the speaker. Without it, the speaker functions at a significantly lower level.


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## keymania (May 22, 2014)

This sound decoder has a speaker baffle already installed. With the tender shell OFF, the sound volume is tolerable, but still not the volume I'm wanting. I'm tempting to cut the coal load and create an upward projecting sound through some kind of custom coal load.

Any comments on this?


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## Hutch (Dec 19, 2012)

How do you like the sound when it's out of the tender for testing? If that's good enough than I think your idea will work. I've been out of this for a while, is this the $45 or $66 one? I know when they came out with the $66 one I was very impressed with the volume and control. I don't remember what the numbers were.


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## keymania (May 22, 2014)

Hutch said:


> How do you like the sound when it's out of the tender for testing? If that's good enough than I think your idea will work. I've been out of this for a while, is this the $45 or $66 one? I know when they came out with the $66 one I was very impressed with the volume and control. I don't remember what the numbers were.


This is the 8-bit Digitrax $45 sound decoder. It's the same wattage as the 16-bit, and I don't expect any greater volume. Maybe the 16-bit custom sound files are produced with a higher output volume.

Now that I've drilled small holes in the bottom of the tender, the sound is better. Would be better projecting upward through the coal load, but I'm loath to drill this visible part. Maybe I'll try a spare tender shell to kit bash and test.


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## Hutch (Dec 19, 2012)

I don't think you'll ever be happy with it. The next model up is much louder and less problematic than yours. It still can't compete for sound with a soundtrax but it's plenty loud. At least I think so.


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## keymania (May 22, 2014)

I can't get the F7 crossing gate horn volume louder than default. Am I missing a CV for F7 volume?


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## Hutch (Dec 19, 2012)

Sorry I can't help you with that, I've been out of it too long.


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## koocnad (Oct 14, 2021)

This may be a dumb question, but I'm looking for the specs/details on the Digitrax SDH166 decoder, but am only finding details on the the Digitrax site for the SDH166D. Does anyone have an old details sheet they can share or is there a special something to finding the older decoder details? Thanks!!


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## Dennis461 (Jan 5, 2018)

old thread, but what details do you need?


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## koocnad (Oct 14, 2021)

Dennis461 said:


> old thread, but what details do you need?


Looking for the standard digitrax document sheet (describing the wiring, etc). I received an older model (can't tell what make it is) and decoder isn't acting right. Want to make sure it's wired right, etc. For example it, in reverse, it runs for a 1/4 inch and stops, then runs another 1/4 inch and stops....


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## Dennis461 (Jan 5, 2018)

koocnad said:


> Looking for the standard digitrax document sheet (describing the wiring, etc). I received an older model (can't tell what make it is) and decoder isn't acting right. Want to make sure it's wired right, etc. For example it, in reverse, it runs for a 1/4 inch and stops, then runs another 1/4 inch and stops....


wiring will be the same as a SDH166D , reset all to default values and try again.


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## koocnad (Oct 14, 2021)

koocnad said:


> Looking for the standard digitrax document sheet (describing the wiring, etc). I received an older model (can't tell what make it is) and decoder isn't acting right. Want to make sure it's wired right, etc. For example it, in reverse, it runs for a 1/4 inch and stops, then runs another 1/4 inch and stops....





Dennis461 said:


> wiring will be the same as a SDH166D , reset all to default values and try again.


So that same wiring diagram document usually has the CVs and other programming details. Would that all be the same as the SDH166D too? For example, which CV I need to change to revert the decoder back to the factory setting?


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## Dennis461 (Jan 5, 2018)

koocnad said:


> ....... For example, which CV I need to change to revert the decoder back to the factory setting?


Go to the Digitrax web site and download the manual.
CV-8 should be the reset CV, but I had no luck setting it with my JMRI programming track.


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