Motor and Sound Decoders for N Scale Kato SD90/43mac and Kato F40PH

Tim Holmes Dec 13, 2020

  1. Tim Holmes

    Tim Holmes TrainBoard Member

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    When I first bought these 2 locos, I made a bad mistake and put in MRC decoders which have been no end of troubles. So I want to replace them. I am looking for some kind of a drop in decoder replacement. Sound is important but moreso is motor control. I run an NCE powercab -- I found the digitrax SDXN146K1E -- which looks good and digitrax is a good name -- but what I am wondering if there is something better -- I googled for Drop In decoder for Kato SD90/43MAC -- and got a hit on the digitrax one as well as some others that are not obviously sound as well as motor decoders -

    So some of you that are DCC gurus -- what do you recommend? and why

    Tim
     
  2. RBrodzinsky

    RBrodzinsky November 18, 2022 Staff Member TrainBoard Supporter In Memoriam

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    I put ESU LokSound wired decoders in mine (but never took any photos). One should be able to install using the Select Direct Micro decoder (73100) which is a semi drop in, but you still have to put in the speaker (or, there are some of us who can do installs).

    The Digitrax decoders are not on the same level as ESU or Zimo, and you will probably want to enhance the enclosure of the included speaker (a good speaker and enclosure is essential for enjoyment of the sound experience), but they are decent.
     
    Tim Holmes likes this.
  3. BigJake

    BigJake TrainBoard Member

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    I have no experience with sound decoders, but I recently bought two new Kato SDP40F locos, with factory installed decoders. One loco has a TCS K7D4 decoder, and the other has a Digitrax DN163K4A decoder. I noticed differences between the decoders, at least in their stock configuration. These were my first two DCC locos.

    1. During programming, the Digitrax decoder alternates the motor direction for pulse responses, so the locomotive does not move very far, even when doing a full read of all registers. The TCS equipped loco moved significantly further, and only in one direction, during programing or reading back the registers. It actually made it most the way around my test loop when reading all registers. If you have a short programming track, make sure you have bumpers on the ends, and if your programming track is part of your layout, make sure you place the locomotive in the right direction to ensure it does not wander out onto the rest of the layout during programming.

    2. The low speed performance of the TCS decoders was significantly better than the Digitrax decoders. I could slow the TCS equipped loco down to a very slow, yet steady, crawl (~1 tie per second). I could not get near that with the Digitrax equipped loco. I have not tweaked their settings, other than setting the address=road#, so it may very well be possible to achieve equivalent (or better) performance on the Digitrax decoder (or both).

    3. TCS has an extensive online library of installation articles, with photos, for their drop-in and semi-drop-in decoders into multiple different locomotives on their website that will be very helpful as I equip my existing fleet of DC locomotives. Digitrax has some articles, but at least the ones I looked at were not as complete or well-illustrated.
     
  4. french_guy

    french_guy TrainBoard Member

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    I did try the MRC1808 sound decoder ($65 on Amazon) a few months ago for my Kato SD90/43MAC...Install was easy, it worked OK, but I didn't think it was worth the money so I returned it. I thought at this time I would get the exact same one but directly from XL Systems for $39......
    But now I think I might just go w/o sound.....sound makes sense wit ESU, but they are much more expensive and no drop in
    So for a no sound decoder, are the TCS (such as K2D4) much better then the Digitrax (DN163K2)?
    @ BigJake: you said you will try to tweak the Digitrax to have the same results than the TCS for low speed......were you successful?
     
  5. BigJake

    BigJake TrainBoard Member

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    French_Guy,

    Sorry, I have not tried yet. May be awhile yet, with Christmas and all...
     
  6. BigJake

    BigJake TrainBoard Member

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    I did a little more research. The TCS decoder, as programmed from the factory, enables Back EMF. I'm still trying to figure out if the Digitrax decoder also does that .

    If the Digitrax does not enable Back EMF by default, or if it's Back EMF is configured very differently than the TCS, that could easily explain the difference in behavior at low speeds.
     
  7. viperjim1

    viperjim1 TrainBoard Member

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    I have purchased and installed the XL sound decoders in my f unit katos roughly 6 and very easy to install and sound great for the money and havnt had a problem yet. I plan on getting more pretty soon.
     
  8. french_guy

    french_guy TrainBoard Member

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    There are interesting threads on nScale.net forum about the XL Systems Inc decoders
    https://www.nscale.net/forums/showt...sound-decoders-with-8-Ohm-Sugar-Cube-Speakers
    https://www.nscale.net/forums/showt...stalling-sound-in-a-Kato-E5-speaker-placement
    https://www.nscale.net/forums/showthread.php?48381-MRC-1960-sound-decoder

    Tons of good info from "Gamitzu"......
     
    Sumner likes this.
  9. french_guy

    french_guy TrainBoard Member

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    Hello
    Have you upgraded the speaker, or are the XL Systems Inc decoders 100% stock in your engines?
     
  10. viperjim1

    viperjim1 TrainBoard Member

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    No they are stock and haven't done a thing to them other than install them. They sound great and the value you can’t go wrong. I’ll pm you and send you my email and if you want I’ll shoot a video and you can hear fir yourself.
     
  11. BigJake

    BigJake TrainBoard Member

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    I like the idea of a truly drop-in installation of these sound decoders and speakers!

    I noticed XL Systems' webpage says they have manufactured all MRC's decoders for the last 20 years. Apparently in the past, MRC decoders had a very poor reputation, but perhaps that was more than 20 years ago. Somehow I don't think they would be advertising that they made the early MRC decoders.

    Fifer Hobby Supply explicitly states on their encoder installation page: "WE DO NOT GUARANTEE SOUND QUALITY OR VOLUME ON MRC DECODERS" (emphasis theirs).

    It also doesn't look like they have a programmable motor braking function. (They have brake sounds!) This is not uncommon in less expensive decoders.

    I'm experimenting with programming in high levels of momentum (using acceleration/deceleration register settings), and using the brake function to stop the train more quickly as needed (also programmable effect, when offered.) Once the train is up to speed (heavy trains take a long time!), cutting the throttle to zero appears to make the loco coast (like your automobile), so you use the brakes (function button) to slow/stop it more quickly, just like driving a car.

    So far I like running this way, and it feels more prototypical, but time will tell if I get tired of it... Or of replacing decoders that don't have motor braking. And of course, changing from a loco that has no brake, to one that does and is programmed to need it, or vice versa, can be maddening.

    Programming high momentum (and then needing braking to slow down faster than coasting to a stop) also allows the sound decoder to more accurately portray the speed of the diesel motor (which follows the more rapidly changing throttle), rather than the speed of the train which changes very gradually. With a steam loco, engine and train speed are one and the same, but not with a diesel-electric.
     
  12. Tim Holmes

    Tim Holmes TrainBoard Member

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    Im suspicious of the fact that they claim to make MRC decoders which are just plain trash, but for the price point for a sound decoder, I cant hardly pass it up, I may have to try when the govt gives me my 1400 of my own money!

    TIM
     
  13. Tim Holmes

    Tim Holmes TrainBoard Member

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    Does anyone know if these decoders feature a point where a capacitor can be added as a "Keep Alive"?
     
  14. Sumner

    Sumner TrainBoard Member

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    I just received a Hard-wired version XL sound decoder to install in a N scale U50. The documentation has MRC on it. I'll probably want to install a keep-alive so looked at it today after seeing your post. I ordered some capacitors to use yester day and probably should of looked first at what was going to be involved in the wiring but think I have it figured out. I'll post what I found but I haven't actually done this yet. Hope to at least get the decoder installed during the next week when I find time and will add the keep-alive at that time if the components have come in. So I just added the following to my site here .....

    http://1fatgmc.com/RailRoad/Decoder-1/page-10.html

    ... but will post the keep-alive info from there here.

    ==== Possible use of a Keep-Alive ====

    The next two pictures show how I plan on connecting a 'Keep-Alive'/'Stay-Alive' if I decide to use one with this decoder.

    NOTE: At the time of writing this I have not done this so proceed on your own using the following only if you feel it is workable. I feel pretty confident that it is all correct but take no responsibility for what you might do. Also the soldering is not going to be easy on the decoder for the negative wire.

    [​IMG]

    On the right end of the decoder above is the bridge rectifier circuit. It is comprised of the four square diodes with 'SL' on their tops. I also enhanced the lines you will find going across them that reference how they are oriented in the circuit. I found reference to how to attach a 'Keep-Alive' to a MRC decoder on the Steamlined Backshop site ( HERE ). Please read that info if you are going to do this and note 'the MRC Decoder Orientation For Keep Alive' diagram you will find there. That is what I used to figure this out.

    [​IMG]

    Above is a diagram of the decoder and the wiring as I found it. You might want to check it out and see if you agree. You might be able to solder a positive wire to the 'Keep-Alive' where the blue wire attaches between two of the diodes. Not much room to work there so the other option is connecting to the blue wire past the edge of the decoder at some point where it might go to your lighting. This is probably the route I'll take.

    The attachment point for the negative 'Keep-Alive' wire is also problematic. You need to connect to a point on or between the two diodes in the upper right corner of the decoder shown above. Again I'm not going to try there as it is too crowded. I have traced that connection point to the left side of the decoder where there is a small unused solder pad or at least it looks like one. Not very large, but there, and the other option might be to the component right next to it.Again only proceed with this if you feel good about what I have found at this point.

    ===================================================================

    I realize that you are probably going to use a different decoder from XL but I'll bet you will find a similar situation as shown above,

    Sumner
     
    Tim Holmes likes this.
  15. Tim Holmes

    Tim Holmes TrainBoard Member

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    Cool, Thanks for the explaination --- looks good!!! The response I got from XL systems when I asked them was

    "Kato best engine in world, no need keep alive" (his words)

    TIM
     
  16. Dogwood

    Dogwood TrainBoard Member

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    Here's an example of a KATO N SD43/90MAC with ESU LokSound V4.0 and sugar cube speaker.

    20210315_194005_copy_1024x768.jpg
     
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  17. MK

    MK TrainBoard Member

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    How much of the frame did you have to mill away?
     
  18. Dogwood

    Dogwood TrainBoard Member

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    A little bit for the board and for speaker with baffle. Between the frames on the backside I've milling a groove for wiring. You need enough space between frames and shell. Carefully check the fit of the shell. You also have to consider the Kapton tape (3/8").
     
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  19. Tim Holmes

    Tim Holmes TrainBoard Member

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    How hard is it to disassemble the frame for milling, obviously you cant mill in place, or you will have metal filings in the gear towers, at the same time, I'd like the gears to stay in TOWERS instead of being all over the desk

    TIM
     
  20. Dogwood

    Dogwood TrainBoard Member

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    It's very simple. There are a lot of YouTube clips on this.
     

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