Digitrax Sound SDN144PS, Plug n Play N Scale Sound Decoder

Mark Watson Apr 25, 2010

  1. Mark Watson

    Mark Watson TrainBoard Member

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    Well it looks like this one from Digitrax has just hit stores and is said to be manufactured specifically for the IM AC-12. It's price point is very attractive, but how will it hold up?

    Anyone here have plans to use it? I do, though I wont be able to order for another few weeks, but I'd love to hear reviews! :D (I like videos too ;))
     
  2. Mark Watson

    Mark Watson TrainBoard Member

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    Bump. Has anyone got a chance to play around with this decoder yet? :)
     
  3. Powersteamguy1790

    Powersteamguy1790 Permanently dispatched

    I have three of them and installed one in one of my four my AC-12's.
     
  4. Mark Watson

    Mark Watson TrainBoard Member

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    So how is it?

    Whats the sound quality like and how is it's motor control?
     
  5. SteamDonkey74

    SteamDonkey74 TrainBoard Supporter

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    I installed a Tsunami 750 in my AC-12. It might have been easier to just wait for this one, but so far I am pleased with the performance of my Tsunami.
     
  6. redone1992

    redone1992 TrainBoard Member

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    Im also interrested in them and how good or bad ?
     
  7. slotcardave

    slotcardave New Member

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    Okay, I got 2 and installed them both into my 2 AC-12's. Install per instructions is a breeze. Real easy, no fit problems. Upon power up here is what happened. Sound Volume is really low. Whistle and Bell sound really good just a little low. Chuff is AC sounding but also very quiet. Adjusted CV58 (master volume) to max 15, very little help. Adjusted CV140 (Chuff Volume) to max 64...no help. Set the locomotive # so I knew system (Digitrax) was "taking" to the decoder. But I could not hear the distintive AC air pumps...I did not try chaning the Air pump type so it could be there. However...the BIG PROBLEM is running. The engine at full tilt "99" in digitrax the engine moves maybe a top speed of 15-20 smph. It barely moves even after a long distance it never gets up any speed. Changed CV2 (vstart) to 2, CV6 (Vmid) to 128 and CV5 (Vmax) to 255...help it get from 15 smph to 20 smph. Still really slow. Chuff increases like it should to a machine gun sound. Put 2nd AC-12 on track and it did exactly the same thing. Did a factor master reset CV8 to 8 and everything ran still the same except the loco # went back to 03 like it should. Any help in this are of the speed issue would help me out. I think I have covered all the basic "1st try this" things and it has moved on to more "expert" type "try this". Thanks
     
  8. Mark Watson

    Mark Watson TrainBoard Member

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    Thanks for the review Dave. Also welcome to TrainBoard!

    That's very interesting on the motor speed. I've read a few reviews of other Digitrax sound products and they all say similar things about the sound quality/volume, but they then say the motor control is usually very similar to that of any other standard Digitrax decoder, which is generally praiseworthy. Hopefully someone else can help troubleshoot this one.

    On the sound volume, I find there are a few different opinions as to what the appropriate sound level should be. I fall into the category of, I should be able to hear it great standing 3-4 feet away, but when the train reaches the other side of the room it should not be audible except maybe the faint whistle sound.
    Would you consider the sound level on the SDN144PS to fit in that category? Or is it not even loud enough to hear when 4 feet away?
     
  9. Babbo_Enzo

    Babbo_Enzo TrainBoard Member

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    Aside the motor control (I can't comment as I don't have the decoder on hand)...
    the volume reported remind me something : I have the same result when I've replaced the factory speaker (32Ohm) on my Sound-only Digitraxx with an oval 8 Ohm I have!
    Then, checking documentation I discover the different impedance, so order a 32 Ohm with my needed dimensions... everything works!

    What I've noted on these Digitrax family is that SDH164D (6 FX3 Functions) mount a 32 Ohm but the SDN144PS (4 FX3 Functions ) mount an 8 Ohm.... but I "presume both share same Sound/motor electronics?
    New Decoder Announcements from Digitrax | Tony's Tips at Tony's Train Exchange.
    ?????????
     
  10. skipgear

    skipgear TrainBoard Member

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    Lowering the impedence of the speaker should make more power from the audio amplifier in the decoder but possibly cause more heat. If anything the speaker should be louder if you go to a lower impedence, but maybe have a little more distortion.

    I don't agree with the baffle instructions in the Digitrax decoder. The tender shell is not a good enough baffle. An enclosure needs to be created or the speaker needs to mounted in the floor of the tender, directly, not in a baffle above the speaker grille. Your sound should come close to doubling it's output if the speaker is in a proper enclosure.

    I have a one of the Digitrax decoders setting on my bench right now, tyring to decide what to put it in.

    As far as the AC-12 speed issue, I think it is more of a loco issue than a decoder issue. The AC-12 I played with seemed slow at 12V. When I bumped the system up to 16V, the loco came alive, this is on DC. The motor they chose is a bit of a power hog I think. Bump up your DCC system voltage to the HO setting (16V) if possible and see how it runs.
     
  11. Mark Watson

    Mark Watson TrainBoard Member

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    Is the impedance related to the speaker's ohm? I did some more reading and apparently the SDN144PS has a processor for a 32 ohm speaker, but ships with an 8ohm speaker. Does this mean that if the 8 ohm speaker is replaced with the 32 ohm speaker, it will be even quieter?

    Also, I found this video on youTube of the SDN144PS installed in a Life-Like E7. I love the look of its gyra-light, and the motor control appears excellent, but the audio leaves some to be desired. However, it feels like the issue is not with the sound produced form the decoder and speaker, but that it is just a terrible sound recording. In other words, it sounds like the decoder is able to make good sound, especially for the 40 dollar price tag. But whatever it was playing was probably not not doing it any justice.

    http://www.youtube.com/watch?v=52EZ--4jRFc


    I hope we can still get some more opinions and reviews here. :)
     
  12. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    Not necessarily. If the decoder's amplifier is designed for 32 ohms, it may not be able to put out enough power to drive an 8 ohm speaker with appropriate volume. Not knowing all the detailed specs (it just says 1 Watt), hard to say what it can actually drive, but my bet would be that with a higher impedance, one could get quite a bit more power out of the speaker (P = R*I^2). (To get 1 watt with an 8 ohm speaker requires 350mA. To get 1 Watt with a 32 ohm speaker requires 176mA. The functions are rated for 200mA.)

    This is different than connecting additional, in parallel speakers. That always has the effect of lowering impedance.
     
  13. DCESharkman

    DCESharkman TrainBoard Member

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    From an electrical standpoint, when impedances are matched, then that represents maximum power transfer capability.

    So if the output stage of an amplifier is 32 ohms, then the optimal speaker is also 32 ohms. This may not have as much effect on volume as it would on signal clarity. The two are not related generally speaking. Volume has more to do with the volume of air displaced by the spearker cone, where the fidelity has to do with the clairty of the signal on the voice coils of the speaker.

    It is the combination of the power delivered and the quality of the signal that makes the sound good or bad. Driving at different impedances may generate more volume, but it will also decrease the clarity.
     
  14. Mark Watson

    Mark Watson TrainBoard Member

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    So for the SDN144PS, you're saying a 32 ohm speaker replacement, to match the 32 ohm processor of the decoder, with a proper enclosure (not using the tender shell as a baffle) will be the optimum set up, correct?
     
  15. DCESharkman

    DCESharkman TrainBoard Member

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    That would be true, if an only if the output impedance of the amplifier was truely 32 ohms.
     
  16. Mark Watson

    Mark Watson TrainBoard Member

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    Ok, I just placed an order for this one! I'll be installing it in my AC-12 and providing everyone here with a complete video sample and review. :D :D
     
  17. Mark Watson

    Mark Watson TrainBoard Member

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    My decoder should arrive tomorrow! :D Unfortunately it may be Thursday until I get a chance to play with it.

    In the mean time, has anyone else used the SDN144PS yet or herd/read any additional information we will benefit from knowing? :)
     
  18. sswjim

    sswjim TrainBoard Member

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    I got one last week, the motor drive is very good, but the sound files for the steam and SD38-2 are not very good. I did put a larger speaker (8ohms) and the volume did increase, but still a bad sound file. I base this on my experience with the Lok Sound and Tsunami Micro's. With them you have many more options. The Tsunami has the correct sound file for the Cab Foward with the weseee air pump sounds. The only good thing about the SDN144PS is the price.
     
  19. Mark Watson

    Mark Watson TrainBoard Member

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    From the video we found on YouTube and reviews of other Digitrax Sound decoders, this is pretty much what I'm expecting. But as far as sound output, do you think this could be a great little decoder (given the price) if we are able to find a better sound file?

    I have high hopes for the motor control, and I expect the volume, though reportedly low, will be just right for my preferences.
     
  20. river_eagle

    river_eagle TrainBoard Member

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    I have so far installed two, one in the AC, (Challenger 3985 sound set)and one in an HO Aerotrain.
    For the AC, I cut the weight into sections so that speaker could mount directly to tender floor, and glued the weight pieces back into the tender around the speaker.
    I set the BEMF CVs (55, 56, 57) all to zero, and speed and performace inproved greatly, so I'm sure that with a bit of tinkering, those can be dialed in for best overall effect.
    As for sound, the supplied speaker works fine, but I'm sure the bigger optional speaker mentioned in the install instructions, would help.
    Decoder can handle an 8 ohm speaker just fine, as that's what I used in the HO Aerotrain, round 18mm 8ohm with enclosure mounted in 1st car.
    Decoder motor functions, as preset were fine for the Aero, with the only adjustment being the standard bump of CV2 to two.
     

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