ESU 58731 LokSound 5 Micro Direct NMRA DCC Sound Decoder - Decoded

Last Updated 231223

ESU 58731 LokSound 5 Micro Direct NMRA DCC Sound Decoder - N Drop-in Board for Kato GS-4, Euro, Japan Type and others (s.a. EM13)

Originally posted on The Railwire: A Forum for Modelers by user peteski, last updated December 06, 2022, 01:11:12 PM.

This information is shared by and republished here with permission of author.


LokSound V5 58731

The LokSound 5 58731 is a decoder designed for plug-n-play installs into Kato models which are equipped with the EM13 format dummy DC plug.  Those are usually used in steam loco tenders, and also in some passenger MU models like ICE4 set.  As designed, that Kato's EM13 interface format is only for motor function, but the decoder also includes three hardwired function outputs (front/back headlights, and AUX1).


Here is a partial diagram of its power circuits. It is handy that ESU decided to provide the raw rectified voltage output (+U), or as it is often provided as the "blue" wire on other decoders.  It is normally used as the common positive for devices connected to the function outputs, and it is a perfect place to connect the positive lead of either add-on stay-alive capacitors, or even a keep-alive module.  Connecting additional capacitance to the B, C, or D circuits is not required or recommended.  I provided those details for informational purposes only.

The negative/common/ground connection is available on any of the green colored areas of the decoder.  My recommendation is to just solder the negative lead of a keep-alive device or capacitors to any of the gold-plated copper visible in the lettering strokes. If needed, the blue solder-mask coating can be carefully scraped to expose more of the copper area.


This is the layout indicating the main components of the decoder (for informational purposes).


Here is the info about the electrical connections. Handy when the decoder will be used in custom installs.  Note that the function outputs (headlights and AUX1) do not have any on-board resistors. Those have to be added externally.

I also included info on trimming the PC board if that might be useful in custom  installs.  I'm planning on trying it in the rear of a Kato wide body diesel (like E8). There is also likely a possibility to trim about 0.1" off the decoder's arms, but I have not confirmed it yet. It should fit nicely over the top of the metal chassis in the rear (while keeping the original Kato light board).


And lastly are the decoder's dimensions.

With only 3 functions  is a rather simple decoder, but I think it might be useful in installs other than just what it was intended for.