Deciding between Digitrax decoders

[gigasaurus]

I am trying to understand the difference between 2 digitrax decoders for use in my Athearn ready to Roll GP60M.

The DH123D says it has Function Output at 2-125 mA.

The DH163 says it has Function Output at 6-500 mA.

Could someone please help me understand what this means? How those mA differences affect me and which I should choose? I'm interested in learning, so it would be great to understand these things.

Thank you.

[locoi1sa]

The 123 has 2 function outputs rated at 125 miliamps. The 163 has 6 output functions rated at 500 milliamps. Two function is front and rear light and six function would give you front and rear plus 2 ditch lights and maybe even number board or any other lighting function.

        Pete

[gigasaurus]

Thanks very much Pete.  So in the 123 features description where it says it supports realistic effects (like mars, ditch lights ...) is that implying if you didn't have a front and rear light, you could hook up 2 ditch lights if you wanted instead (to take advantage of the "2" lights supported)?

Also, this is a newbie question: when its rated at 500 mA does that mean you need light bulbs that can handle that current?  Or does the difference in those 2 ratings mean that lights are brighter?

Thanks again.

[rrinker]

 2 function decoders only have front and rear lights. Not all effects are supported on the DH123. So just ditch lights and no headlight will likely not work with that decoder. If you want the headlihgt plus ditch lights you will need at least 3 functions, 4 is a more common number.

 The current rating is a bit of onconsistency in Digitrax's documentation. The DH123 has 2 functions, each of which can handle 125ma. That means you can apply up to that much load without burning it out. Use LEDs, they don;t heat up the shell and draw just a fraction of the current. Light bulbs, definitely hte 1.5V ones Athearn uses, need resistors, which also generate heat. Even a 14V bulb usually needs a resistor, because incandescent bulbs have inrush currents which can exceed the function rating on the decoder. Boo Athearn for still using light bulbs after every other manufacturer has switched to LEDs.

 The DH163 has 6 functions, buit each one cannot handle 500ma, 500ma is the total you are allowed to draw from all 6 at the same time. Each individual one can handle 125ma, but you cannot load all 6 to that level, that would require 750ma.

 One thing to keep in mind - you are NOT limited to using decoders only of the same brand as your DCC system. As such, might I suggest TCS, they have much better motor control than the Digitrax decoders, they work better with LEDs (LEDs require different ways of dimming them than incadescent bulbs), and the TCS web site is filled with pictures of installs which you can use to help with yours. If your loco has a 9 pin plug on it, you can get a T1A and just plug it in, that has 2 functions for front and rear lights, or you cna get the T4A which will plug in and has 2 extra functions for ditch lights. If you need more, there's the T6 which has 6 functions, so you can have the headlights, ditch lights, and a beacon on the roof or something.

 Here is the install in the GP60:

http://www.tcsdcc.com/public_html/Customer_Content/Installation_Pictures/HO_Scale/Athearn/GP60/GP60.html

 

           --Randy

[richhotrain]

Great reply, Randy.  Thanks for sharing.

A lot of people, myself once included, don't understand a lot about decoder selection.

The number of functions clearly influence the capabilties of the decoder as it relates to the lights display and operation.

The current rating is critical to avoid damaging the decoder or burning out the lights.

As far as incandescent lamps are concerned, I learned the hard way by installing a 12 volt incandescent lamp in my prized Proto Heritage NKP 2-8-4 and melting the number boards.

And, lastly, when it comes to lights, incandescents versus LEDs, Athearn wins the booby prize.

Rich

[MisterBeasley]

The DH163 decoder supports plugging in a Sound Bug, the Digitrax low-budget add-on sound only decoder.  The DH123 does not.

Have you thought about sound in this engine?  If you're planning to eventually add sound, you'd might as well do it now.  Tsunami and LokSound are probably the ones to look at.  By the time you put in a DH163 and a Sound Bug, you're close to the price of one of the high-end decoders, but no where near the quality.