adding sound to old Athearn GP38-2

Discussion in 'Scratchin' & Bashin'' started by scottcn, Apr 28, 2007.

  1. scottcn

    scottcn Member

    I have an old (~15 y) Athearn GP38-2 that I would like to upgrade to DCC with sound. One problem is figuring out where I could put the speaker. My first thought was to replace the molded-on radiator fans and/or screens with something see-through and then mount an upward-facing speaker under them.

    Does anyone know if the Cannon and Co. fans are actually see-through? From my Walthers catalog, I can see that there are several levels of detail but I can't tell if the fans are open on the bottom (i.e., sound could get through) or not.

    Any alternate suggestions for speaker placement?

    The unit runs pretty well (or rather, used to before I broke part of the truck assembly while dismantling it but that can be fixed) so I'd like to upgrade the engine rather than just buying a new engine with sound pre-installed. Besides, this GP38-2 was my first good (non-trainset) engine back in the day so it has some sentimental value as well.


    - Scott
  2. Squidbait

    Squidbait Recovering ALCO-holic

    I think that the problem you're going to find with this unit is not so much having an opening for the sound (less than crucial), but finding a decent-sized speaker to fit in the shell. It's pretty tight in there. Unless you're willing to sit it in the cab, you'll have to stuff it under the radiator fans. The shell is narrow - you won't get a 3/4" speaker in there easily.

    As for cutting the shell to get louvers or fans, I wouldn't worry too much about it. The sound will get out the bottom, and all you're going to lose are the high frequencies, which with such a tiny speaker you're going to have in abundance.

    That said, if you're willing to go the extra effort and upgrade the fans, the Canon ones are see-through, as are the Smokey Valley ones.
  3. UP SD40-2

    UP SD40-2 Senior Member

    Scott:wave:, i would put the speaker in the cab, honestly its really the ONLY place you CAN put a decent sized speaker:wink:. 99% of my engines have the speaker in the cabs. don't worry about "holes" for the sound to get out, more the enough sound will make it out without putting any openings in the shell. :mrgreen:-Deano
  4. scottcn

    scottcn Member

    Thanks Squidbait and Deano! Not having done this before, I thought that the sound would be muffled if I didn't have any openings in front of the speaker. Glad to hear (no pun intended :-D) that isn't a serious issue!

    Now to find a suitable speaker and the money to buy a DCC-sound decoder. Unfortunately, the hobby budget is a bit thin now :)() with all the spring-time gardening and home improvement work going on around here.

    Thanks again for the help guys!
  5. Squidbait

    Squidbait Recovering ALCO-holic


    You might be able to fit a Miniatronics 15mm x 25mm speaker in the space over the rear truck, under the rad fans: [​IMG]

    It'll depend on the sound decoder you choose. I did one with an MRC decoder, and had to mount it in the dynamic blister, just because it was too wide to fit anywhere else... lots of cutting and filing.

    The other thing you should be aware of is that you get what you pay for with respect to sound. I'm not too impressed with the current line of MRC sound decoders... they sound pretty cheezy to me. I haven't heard their new Brilliance line yet, so maybe they're better.

    The Soundtrax decoders are pretty decent, as are the Loc-Sound ones. The QSI ones in the Proto 2000 and BLI locos are decent too, but AFAIK, they're not available separately.
  6. scottcn

    scottcn Member

    Squidbait, Thanks for the insight into decoders and speakers. After looking around tonight, I think I am leaning towards a LokSound decoder. Will need to get out my GP38-2 and measure to see how big of a speaker I can cram in there.

    Thanks again for the helpful advice. I just love this place (white background and all :))!!

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