Decoders - Why so many different ones?

[Anonymous]

[?] I am new to the DCC systems and do not realy understand why a manufacturer say "DIGITRAX " would offer so many different decoders. I can understand one with sound and one without. Is it that each year model as a new number or ?
Thanks for any and all your help.
ennout

[cacole]

There are many different decoders because there are many different locomotive manufacturers, and no decoder can fit every one of them. Some locomotives require specialized decoders that are in the exact same shape as the constant lighting circuit boards that are in them. Kato, Atlas, Proto2000, Bachmann, etc. each require a different shaped decoder.

[Anonymous]

Beyond loco specific decoders, there are also issues of size, number of functions, and current draw to be considered.

[BR60103]

I just read an article on adding DCC to a Japanese 6 unit electric train. This required a decoder in each car, and 3 different types. End units had interior lights plus headlights but no motor; coaches required lights only and the power car required motor and interior lights but no headlights.

[hdbob]

ok so how do you know what decoder to buy?

[tstage]

Richard & Bob,

Go to a web site like Tony's Train Exchange, Litchfield Station, or Loy's Toys and get their recommendation. You can also e-mail or contact the manufacturer of the locomotive in order to get their preferred decoder recommendations, as well. Tony's web site is very helpful because he has the decoders listed so that you can compare prices, features and/or shortcomings:

http://www.tonystrains.com/productcompare/decoder_comparison.htm)

There is usually a price to fit all pocketbooks.

There's also a handy link on Tony's main page called "DCC for Beginners" that you may find quite helpful to you. Here's the link to Tony's web site:

http://www.tonystrains.com/index.html

Tom

[jfugate]

Here's a general guide so that you know which kind of decoder to buy.

FLEET DECODERS
Cheap low-end decoders ($20 price range), also called *fleet decoders* usually have basic motor tuning capbilities, but don't have extra features to tune loco performance like back EMF. Also cheaper decoders tend not to have any extra function features like gyralights, rotating beacon, or ditch lights.

But these cheap decoders are *ideal* for outfitting a lot of locomotives cheaply if the locomotive already performs well on straight DC and you don't need anything beyond a basic headlight. (Most modern locomotives run very well, so are great candidates for fleet decoders)

FEATURE LOADED DECODERS
Fancier decoders ($25-$40) usually have back EMF and lots of extra lighing functions. Back EMF enables the decoder to tell how hard the motor is working and compensate for it, making loco performance smoother. This is most often useful if the loco has a tight mechanism or you run on tight curves or through lots of complex trackwork.

Applied and tuned properly, back EMF can make a loco glide through complex trackwork with a silky smoothness that's hard to achieve any other way. But you can overdo back EMF so the loco will run at a constant speed up hills, down hills and around curves without you ever needing to touch the throtte. While a cool trick, that's not very realistic and can lead to montony in a real hurry.

More to come in this discussion in a second post ...

[jfugate]

More on deciding which decoder to buy ...

SOUND DECODERS
The next price bracket up ($70 - $150) in decoders involves the addition of sound. Sound decoders typically also have motor control features. Pricing at the low end generally has fleet decoder level motor control, while pricing at the high end either adds sound features or begins to add more feature-rich motor control, adding things like back EMF.

Sound decoders depend on function keys to provide various sounds, so you will need to make sure your DCC system throttle has lots of f-key capabilities (F8, F12, or even more) if you intend to do a lot with sound in your locos.

DECODER FORMAT VARIATIONS
The other thing that affects decoder variety is the decoder formats, as in different ways they can be mounted in your loco. Here's a basic rundown on the common formats (each of these will be a different decoder type):

- No plug ... just wire pigtails you have to hardwire in
- 9-pin edge card ... no wires, just connects to a 9-pin edge connector
- 8-pin decoder plug with short wire pigtail (plugs into loco circuit board)
- 8-pin decoder plug with long wire pigtail (plugs into loco circuit board)
- 8-pin decoder plug built into decoder ... no wire pigtail at all
- Athearn loco harness for Athearn locos with no circuit board
- Kato/Lifelike circuit board replacement (decoder replaces loco circuit board)
- Atlas/Genesis circuit board replacement (decoder replaces loco circuit board)

So now take the 3 main decoder categories I listed, then multiply them by all the installation formats I show above and you can see how you can get all the vast array of decoder options listed.

[BR60103]

And multiply in a few other qualities like amperage/motor load ...

[Tilden]

There are a lot of different decoders to make things easier for the modeler. Depending on your comfort level with electronics, it is Possible to wire up any loco with a basic fleet decoder with plain wire harness. Possible, but not easy. Selecting (and paying for) a decoder specifically designed for a given unit that just drops or plugs in, saves a lot of time and frustration.

[claycts]

QUOTE: Originally posted by hdbob

ok so how do you know what decoder to buy?

Easy ask Randy or Spacemouse they are both a walking base of information. Glad you asked I was wondering why there was not a fits all and them some for just certain units.