SA-DEC-4-DC & S-DEC-4-DC from LDT (Littfinski): 2 sturdy accessory decoders used underย the biggest model train layout in the world!
LDT (Littfinski DatenTechnik)
LDT is a (medium-sized?) manufacturer based in Germany, though their website is available in a few languages. They have a large range of DCC (and Motorola) products for digital model trains.
Iย suspect not so many people have heard of LDTย (I hadn’t until I started shopping for trains in Germany). Why do I have those modules, and why are they worth mentioning here? Two reasons:
- The decoders are available (at least) EU wide. They are indeed sold by the German chain store Conrad Electronics, that I often mention here. This means the decoders are available through the nationalย Conrad websites (conrad.de, conrad.nl,ย conrad-electronic.co.uk…) and through the global Conrad.com.
- LDT products are used under many large layouts. Including the largest & awesomest model train layout in the world: the Minatur Wunderland in Hamburg. LDTย describes in details which models are used in Hamburg on this page.ย That sure speaks well for the reliability of the LDT modules.
Specs & pictures
Theย SA-DEC-4-DC & S-DEC-4-DC are two completely separate devices. They look alike, andย it made sense to review them together since they share a very common purpose under our layouts:
- SA-DEC-4-DC – DCC 4x Relay decoder (German:ย Schaltdecoder)
4 independently operated bi-stable relays ย (for any item that needs constant power, e.g. lighting).
- S-DEC-4-DC – DCC 4x Switch decoder (German:ย Magnetartikeldecoder)
For 4 double-coil switches (for standard N-Scale switches with coils and 3 wires).
Ready to use or DIY kits
Before having a look at theย SA-DEC-4-DC & S-DEC-4-DC decoders, a few words about the LDT philosophy.
Most modules are available in 3 versions:
- DIY Kit – read to be soldered with the board and all needed components
- Ready to use board
- Ready to use board with plastic housing.
Obviously, the DIY kits are cheaper. Since the components are normal-sized, anyone with a bit of soldering experience should be able to build the modules successfully (20-30 minutes).
Conrad seems to onlyย sell the first 2 versions, but you can buy the separate plastic housing if you want to:
- SA-DEC-4-DC – DCC 4x Relay decoder
DIY Kit: ย Conrad no.ย 212172
Finishedย board:ย Conrad no.ย 212180 - S-DEC-4-DC – DCC 4x Switch decoder
DIY Kit:ย Conrad no.ย 212113
Finishedย board:ย Conrad no.ย 212121 - Plastic case LDT-01 for both models: Conrad no.ย 240015
Programming
Those modules are, by design, extremely simple. There are no CVs, no complicated settings. For both decoders, programming is done the old fashioned way, in a few seconds.
Just press the programming button, send an order from your command station, the module then takes the corresponding address and the 3 following (e.g. send 1, modules gets addresses 1 to 4).
Tests and impressions
The switch decoder works well with classic pointsย (in my case, Fleischmann N).
Unfortunately, the relays on the relay decoder are a bit noisy. This is not unusual, since relays are actual mechanical devices. I use these to switch some layout lights on and off.
I have had those modules under different versions of my layout for more than 4 years. Some I had bought as DIY kits, othersย as ready to use modules. Those modules have always worked completely reliably, although my layout isn’t as intensively used as the Hamburg Wunderland !
Conclusion
The LDT switch and relay modules are single-purpose no fuss devices. They do little, but they do it very well. Programming couldn’t be easier, and if you can solder, the DIY kits will save you a bit of money (e.g. as of July 2014, the switch decoder for 4 switches costs about โฌ21).ย Beginners can get the ready to useย devices.
My personal choices have evolved. Because my layout is always evolving, I now prefer to buy universal modules. Those can be reprogrammed for any purpose (switches, lights, signals). The drawback is they areย more complicated, and sometimes more expensive.ย I recently reviewed the advanced Qdecoder Z2-8+ย which is now one of my favorites.
Despite this change of heart, LDT modules still operate many essential parts of my layout. I would still recommendย them to people looking for simple & reliable DCC devices.
External links
- The official LDT page for the switch decoder (“Turnout decoder”):ย http://www.ldt-infocenter.com/dokuwiki/doku.php?id=en:s-dec-4
- For the relay decoder:ย http://www.ldt-infocenter.com/dokuwiki/doku.php?id=en:sa-dec-4
The relay decoder is erroneously called “switch decoder” in English by LDT. Do not confuse it with the actual switch decoder, called “Turnout decoder” by LDT.
I always try to be fair and square when giving grades, see the details about the evaluation criteria here !
Reminder: I am a hobbyist and these articles only represent my personal views. I am not receiving any compensation, in any form, from the brands or stores mentioned here. The product names, marketing names, and brands mentioned here are the property of their respective owners.
LDT is known by several hobbyists (at least by me!). Donโt
know about the switch controllers, but I have few of their S88 occupancy
detector modules which perform very well. Available in France in specialized
hobby shops.
Thanks Alain. I wasn’t so lucky, in France for 7 years, I never heard about LDT ๐
Don’t hesitate to share French retailers that you would recommend, so I can mention them on the FR version of this post!