Chuff and steam loco sounds without movement.

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#1
I have converted one of my DC steam locos to Digitrax DCC with sound. On this loco, in particular, The chuff and stuff starts before the loco starts to move, which is about 10 on the controller. It will sit there chuffing away at a good clip without any movement unless I shut it down or wind on the speed knob. I know there is no cam synchro with this setup but it just seems strange that the two functions are completely separate. I have read the Digitrax documents and can't figure it out. It wouldn't be so obvious if the loco started moving with less voltage and I have had no luck affecting that through programming. Any ideas?

Oh, another thought is that I have been unhappy with the puny sound from the Digitrax compared to my BLI loco with Paragon 3. But it just dawned on me that the Digitrax sound would be fine and proportionate with N scale but it is wimpy for HO, even with upgrading to a sugar cube speaker.
 

Iron Horseman

Well-Known Member
#3
I have converted one of my DC steam locos to Digitrax DCC with sound. ..... I have been unhappy with the puny sound from the Digitrax compared to my BLI loco with Paragon 3. But it just dawned on me that the Digitrax sound would be fine and proportionate with N scale but it is wimpy for HO, even with upgrading to a sugar cube speaker.
How did you mount the speaker? Which brand of "sugar cube" speaker & enclosure did you use?
 

Iron Horseman

Well-Known Member
#5
The speaker was mounted in the tender, which had several holes drilled in it. It was actually small enough to mount in the cab roof if I wanted to but I had already drilled the holes for the Digitrax speaker. https://tonystrains.com/product/tds-supersonic-small-speaker/
https://tonystrains.com/product/tds-supersonic-small-speaker/[/QUOTE]Interesting Interesting, unfortunately I've never worked with that particular speaker. It says "enclosure sold separately". Did you get their enclosure for it or build your own?
 
#10
How did increasing the value of cv2 work out?
It was already set to 10. I tried 15 with no change. I kept increasing it by 10's and 20's and got up to 100. At that point, the loco started immediately on step one. Looks like this might be the answer. I will start dropping it a little at a time until I can get a soft start. I will let you know what number I ended up with. Thanks for your help!
 

Iron Horseman

Well-Known Member
#11
I got their enclosure. The speaker snaps in.
The speaker was mounted in the tender, which had several holes drilled in it.
Sorry to ask so many questions but trying to visualize what is really going on. Are the holes drilled in the bottom or through the "coal" on the top? I guess I'm wondering how many of those holes the sound can get through. How did you affix the enclosure to the speaker - silicone? If so are you certain none of the silicone oozed on the inside onto the speaker "cone"?
 
#12
Sorry to ask so many questions but trying to visualize what is really going on. Are the holes drilled in the bottom or through the "coal" on the top? I guess I'm wondering how many of those holes the sound can get through. How did you affix the enclosure to the speaker - silicone? If so are you certain none of the silicone oozed on the inside onto the speaker "cone"?
The holes are drilled through the coal. The sugar cube speaker has no cone. It is flat and neatly snaps into the enclosure. Check the link I attached previously. The speaker sits on top of the decoder held in place with double sided tape. The sound is a bit crisper than the original Digitrax speaker. I tried both of them without the tender shell on and very little volume is lost once assembled. This is my first experience with Digitrax decoder conversions. I don't know how the volume would compare with other brands of decoders. My milepost is the BLI Paragon 3 that is very loud. Every sound on my Digitrax conversion is very soft. The chuff isn't audible when another train is running and the whistle is very week. The bell cannot be heard unless the tender is right in front of you. I tried some of the diesel sounds and they were much better, especially the horns. There is a choice of several diesel programs but only 2 for steam. The one I am using is the better of the 2.
 

Iron Horseman

Well-Known Member
#13
The holes are drilled through the coal. The sugar cube speaker has no cone. It is flat and neatly snaps into the enclosure.
Yeah, that is why I put "cone" in quotes, that flat surface is the part that vibrates and acts as the cone. If it is hindered by something it will effect the sound.

The speaker sits on top of the decoder held in place with double sided tape.
In my opinion the speaker needs to be anchored solidly to something frame or shell, but even that would not account for such a weak signal as you indicate. Frankly I'm baffled. Perhaps I should have started with two obvious questions. Which exact decoder is this, and have you checked the value of CV-58? I say CV-58 because the Digitrax sound decoders I have, use that for the master sound volume? By default the one I am looking at (SDXH166D) has it set to 9 of 15.
 

Iron Horseman

Well-Known Member
#16
Already at max volume. Bummer, I was hopping that would do the trick. My last guess would be maybe a bad capacitor? To answer your question, I've not used that unit in a while, but don't recall having volume issues.

As for the synchronization issues, with that decoder model, look at CV-133. Supposedly if one measures the diameter of the driving wheel (in scale inches), and enters that value into CV133 it should synchronize electronically. How I don't know, as the wheel could be hooked to the motor with an infinite posibities of gears & ratios. But is should be an easy way to slow or speed up the chuffs to match the wheels. The SDH166D manual also says the white wire on the sound harness is for a synchronization cam when combined with setting CV133 to 128. None of that, for any settings there in, explains why it would sit there and chuff with no motion. !?!!

Sorry I think I am out of, ideas / suggestions.
 
#17
Already at max volume. Bummer, I was hopping that would do the trick. My last guess would be maybe a bad capacitor? To answer your question, I've not used that unit in a while, but don't recall having volume issues.

As for the synchronization issues, with that decoder model, look at CV-133. Supposedly if one measures the diameter of the driving wheel (in scale inches), and enters that value into CV133 it should synchronize electronically. How I don't know, as the wheel could be hooked to the motor with an infinite posibities of gears & ratios. But is should be an easy way to slow or speed up the chuffs to match the wheels. The SDH166D manual also says the white wire on the sound harness is for a synchronization cam when combined with setting CV133 to 128. None of that, for any settings there in, explains why it would sit there and chuff with no motion. !?!!

Sorry I think I am out of, ideas / suggestions.
I have been all up and down with CV-133 and I think the closest was with a setting of 125, based on trial and error. That is where I am now. There is no syncro cam and the white wire is clipped off. I did hear back from Digitrax and they said to increase the starting voltage which I did, again trial and error. Now, the loco starts right on level 1 so the chuff isn't a problem. It starts abruptly at level 1 which I wish was a little softer but it doesn't sit there and chuff with no place to go.
 



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