Declamations on Decoders: 2

A while back I promised to update y’all on my Digital Command Control (DCC) saga. Not one to break promises (albeit tardily), here are a few updates.

First: Last time I was singing the praises of the little Digitrax DH-126 decoder. While it’s still tough to beat it for affordability, experience has introduced a couple of caveats.

  • First up: I left the power on to the railroad one night. Next day, two of my units had lost headlights. A few hours shouldn’t blow new bulbs. And, one of them now has a weird thing where the lights will come on for a few seconds, then fade out. Did the decoder overheat? Whenever I get a couple of replacements, I’ll experiment and see if it’s the decoder, or the adapter board causing the problems.
  • Second: It’s getting hard to source them. It’s probably due to this worldwide semiconductor shortage, but it took four months to get TWO of them from one of my train pushers.
  • Third: I discovered that Soundtraxx makes a non-sound decoder board that prices out in the $25 range. While slightly higher than a plain-jane DH-126, you don’t need an adapter board this way, so you’re now about $20 to the good. Plus, these boards have six function outputs. AND, they have a lower profile than the combined adapter/decoder, so they fit very well in confined spaces, such as a geep. The downside is that the function outputs all run at 12 volts, so you must install resistors for lighting effects. In my case I generally use the 1.5-volt microbulbs, which require a 330-ohm resistor in series with each bulb. (That can be as many as six for a single loco.) Fortunately you can buy a pack of 80 resistors on the ‘bay for about three bucks. Keep them on hand. I don’t know the LED resistor value, but online sources indicate it’s somewhere around 1000 ohms. Your mileage may vary.

Second: As promised, I tried installing decoders in a couple of locos which already contained LED headlight circuits. Result? SCORE! These circuits are designed to step down 12 volts to somewhere around 3.5v or so, in the LED safety range. That was always a bit of an issue when running on variable 12-volt-max DC control (lower voltages would not always power up multiple LED’s), but the aforementioned Soundtraxx decoders put out a nice steady 12 volts, and the headlights work famously. The only downside to this is that I had wired the circuits to combine headlights and ditch lights, so I can’t control them separately. But wow, do they light up the landscape. I’m not sure if I will build any more, but these work great. This tells me that the incandescent-bulb circuits in some other units should also work great. That’s the next conversion to come.

Now my Ski Train leader and one of my SP AC4400’s are rockin’ the candlepower!

Third: Sound decoders. I now have a total of five sound-equipped units. I put in another Econami system into an F40PH, the trailing unit on my Ski Train power suite. That EMD 645 sounds fantastic. The fourth installation is actually a factory-equipped unit from Athearn, an SD40M-2 that I just had to have. It has a Tsunami in it. No complaints whatsoever. Well, one. The lights are a bit dim; I suspect the resistor values may be a bit on the safe side.

The fifth one was an experiment with 8-bit sound, an EMD 710 unit from XL Systems. It has the decoder and speaker all for about $45, which would be quite a bargain if it worked out. I’m sorry, but it is just terrible. The loco controls work very well, but the sound quality is reminiscent of crinkling cellophane. Just reedy, and kind of painful. I won’t be buying any more of these. Oh well, live and learn. Sorry, guys.

Next up: two little projects. Thanks to a promo at Soundtraxx, I ended up with a nice Tsunami 2 sound decoder for GE diesels, free. The only issue is that it’s a 21-pin design, and I have no compatible boards. Once I make a decision on which unit gets it, I’ll find a compatible board and do that installation. The other project is to put one of those non-sound Soundtraxx boards into a blue-box GP60 I have that has a strobe circuit installed. Plenty of functions available to drive a little flashing LED! That one should (hopefully) be quick.

OK, that’s it for this time. Next DCC update will be later in the summer, unless something changes. Meantime, check out some of my non-model railroad blog posts. You may like them.


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