MRC Sound Decoder for Kato SD70MAC

Discussion in 'N / Z Scale Model Trains' started by dwight77, Mar 6, 2011.

  1. dwight77

    dwight77 Member

    Hi All:
    I subscribe to Model Railroad News and have found many of their articles very informative. Recently, in October 2010 and February 2011, they had articles espousing how good an MRC decoder with sound was when installed in an N Scale Kato SD80 and a Kato SD45. Since I have a couple of Kato SD70MACs, I was eager to try the MRC decoders. BIG BIG DISAPPOINTMENT. Following is the "Letter to the Editor" that I wrote with my results. Suffice it to say, I won't be purchasing any more MRC decoders with sound until I can see and hear SIGNIFICANT improvements.

    Letter to the Editor
    I eagerly read the article by Steven Goehring in your October issue, Locomotives/Rolling Stock on “Kato’s Big MAC’s a Whopper Deal” about Kato’s SD80MAC and the use of MRC’s 1808 drop-in decoder with sound. Since I have several Kato SD70’s I was hopeful that there might be good things on the horizon for sound in N Scale diesel locomotives.

    In the article, Mr. Goehring reviewed the simplicity of the installation of the MRC 1808 drop-in decoder and some adjustments he made. He then stated, “When I started running the newly sound equipped SD80MAC, I knew I had a winner. It sounded fantastic and my-oh-my, how it ran!” I thought WOW; things are looking up for N Scale sound!!

    Then after the holidays came your February edition and the article, again by Steven Goehring, “Kato delivers quality DCC ready SD45 to N-Scale” and in the article, the sub section “The Big New Feature DCC (and Sound!)”. Again Mr. Goehring had installed an MRC drop-in decoder with sound (#1806-2). He summarized with, “So, with DCC and sound, how does the SD45 run? VERY well, thank you very much!...The sounds are crisp and clear,...This locomotive is simply a joy to operate.”

    I was ready. I checked and found that MRC had a comparable drop-in sound decoder (#1644) built especially for my Kato SD70MAC. I placed my order and eagerly awaited its arrival, presuming it would be equally as good as the ones in your articles. It arrived, and as described, the installation was quick and easy. I put my locomotive on the program track, picked a bell and horn sound and then set the prime mover sound. And then……??????......where is the sound……?????. The horn and bell were audible. To hear the diesel sound, I had to be on top of the unit. I went back to the program track to check the volume….it was maxed out. I looked at every possible adjustment but nothing improved the volume.

    Bottom line, I think the speaker is just too small, not more than ¼ inch in diameter, to produce good volume….I didn’t expect to hear it from 20 feet away; but it would be nice to hear it clearly at 10’-15’. But, it just wasn’t the case in this model configuration…..a BIG BIG DISAPPOINTMENT after reading your articles.

    I am going to look into possibly mounting a larger speaker in the fuel tank to see if I can salvage the decoder purchase; but at this point, I will not be purchasing nor recommending anyone purchase the MRC 1644 drop-in sound decoder for Kato’s SD70MAC. I know it is not one of the exact decoders reviewed in your articles, but I would be hard pressed to think that the results would be much different.

    I greatly enjoy your magazine, please keep up the good work.
    Dwight Sedgwick
    North Fort Myers, Florida
  2. dwight77

    dwight77 Member

    Just for grins, I sent a copy of my "Letter to the Editor" to MRC to see if they had any comments. Below is my email to them and their response. It is almost too funny. To even think that they would market a sound product that they expected to be heard a whopping "almost 1 foot away" is borderline criminal.....and then it better be a silent running mechanism in your locomotive and in a dead silent room.

    Email to MRC
    To: Model Rectifier Corp.
    Having read two reviews in Model Railroad News which combined N Scale Kato Diesel locomotives (SD80 & SD45) with your specifically designed train decoders with sound, I was hoping for a great outcome when I purchased your #1644 decoder with sound specifically designed for my Kato SD70 locomotive.
    Unfortunately, I have not had a good experience and I wrote a "Letter to the Editor" at Model Railroad News (copy below).
    I felt it necessary to also send a copy of the letter to you as it is your decoder I tried to use. I would appreciate any suggestions or guidance you might provide. Your decoder was truly easy to install and it ran the locomotive fine, there just is not any volume to the sound.
    Dwight Sedgwick

    MRC Response
    From: Frank V
    Subject: Re: MRC Decoder with sound

    due to the speaker size needed for n scale the volume is not going to be that loud
    normally you should be able to hear the prime mover up to almost 1 foot away...the bell and horn up to 2 feet..this also depends on gear train/mechanism noise from the loco and how quiet the room is.
    if you need more volume you can use a bigger 8 ohm speaker if you can find room for it inside the loco
    we can not supply a huge speaker with the decoder, because it needs to be made so everyone can install it without any major modifications to the loco
  3. Denyons

    Denyons Member

    Hi Dwight,
    I aquired 2 MRC sound Decoders and had the same audio problem due to the tiny speaker.
    I had an H.O. 8 ohm speaker and set about drilling out the frame of my Kato C44-9 loco inside the plasic fuel tank cover to try to fit it. It took a few hours of work to get the speaker to fit in the cavity but I finally had success. I then cut out a rectangular hole for the sound to escape and covered the hole with a piece of very fine screening gluing it in place.
    The wiring was easy as it is just 2 wires to solder onto the speaker after cutting off the small one that came with the decoder. You will need 2 small lengths of wire as it has to reach to the fuel tank area. The sound is now excellant and I am very happy with it even though it was a large amount of work.
    I went through all the sound CVs and chose the ones that I liked best and the results are great.
    I am going to install another MRC that I have but I will try to get a thinner speaker which would take less grinding and milling.
  4. Denyons

    Denyons Member

    Re MRC Sound Decoders
    I forgot to mention that you must make sure that you tape all the cavity before setting the speaker in place to prvent any shorts.
    I used my Multi Meter to check accross the the 2 frame halves to be sure there was no continuity.
  5. dwight77

    dwight77 Member

    This may not be the answer for everyone, but making a “sound box car” has really brought me to a new level of satisfaction in N Scale sound. I used a Micro Trains 50’ Express refer for my project. Additional parts (with approximate costs) were:
    Digitrax SDN144PS Sound Decoder $ 39.10 (Litchfield Station)
    14 x 25 mm 8 ohm speaker $ 5.89 “
    1000 uf 16V capacitor $ 1.59 “
    100 ohm ½ watt resistor $ .15 “
    Richmond Controls axle wipes & bolts $ 3.82 “
    Richmond Controls connectors $ 1.00 “
    Micro Trains 50” refer $ 16.00 ( e-Bay )
    Total $ 67.55

    I used the wiring diagram from Streamlined Backshop Services ( Streamlined Backshop Services Sound Car Kit_Instructions.pdf ) and followed their recommendations on the CV settings on the decoder since I did use the resistor. I did not drill all the holes they show in the car base, but instead built a speaker enclosure out of styrene and mounted the speaker facing upward. In using the refer, I found that in opening the roof hatches, the sound volume was greatly increased. So I glued the doors open, otherwise I was going to loose them for sure.

    The basic sound on the decoder was ok but I found that in downloading the Digitrax sound file for the SD70, I had really good sound. In fact, I may end up turning the volume down a bit, especially when I use it on my home layout. But when my club goes to a show, and we take our N-Trak layout, which is over 20’ long, people won’t be guessing on whether they can hear sound…..they will.

    Another nice advantage in using the Digitrax decoder, by installing the resistor, you can program different ID’s. So I can take the sound car, program a loco number that I want to use it with, and off I go. If I want to run it with a different locomotive the next day, just reprogram the number, and you are ready to run. Also, in using the refer, it doesn’t look out of place immediately behind the locomotive.

    Following are three pictures:
    Top view showing the parts and speaker facing upward:

    Side view, the connectors made life easy:

    Bottom view of the axle wipes. The Richmond Controls axle wipes seem to let the trucks rotate much easier than the wipes that rub against the side of the wheels:

    My plans are to make four sound cars which should give me lots of flexibility, expecially since I can reprogram them as I use different locomotives.
  6. Denyons

    Denyons Member

    God job Dwight. The only drawback would be when you have a engine uncoupling from a train and running into an engine house alone or, pulling out of the engine house to pick up a train.
    Godd idea though for keeping the sound car on a coninuous train.
  7. SR39

    SR39 Member

    Had the same problem with MRC and got basically the same response from them. The problem is not necessarily speaker size. I have 4 Kato E8's with Digitrax SoundFx decoders in them and they are 100% better. Speakers are the same size. I also have 2 BRI E8's that came with Paragon2 sound pre-installed and they will blow you away. They come with the ability to turn the sound down by pressing F8 quickly, which I have had to do. They can compete with our club's HO sound equipped engines with no problem.


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