The NEW home for the "OLD" Tutorials Tip & Tricks

Tutorials, Tips & Tricks -->>

Tutorials, Tips & Tricks -->>


Email or call 317-201-4974 to discuss your project today!



Streamlined Backshop Services is an authorized dealer for all major DCC manufacturers including:


CT Elektronik

DCC Specialties


ESU-Electronic Solutions

Lenz USA

MRC Corporation

NCE Corporation

QSI Solutions



TCS-Train Control Systems

Zimo USA


Be sure to contact us if you don't find what you are looking for.  We can ship most items in 5-7 business days.



Be sure to visit our YouTube channel at 
Streamlined Backshop Services to see video demonstrations of some of our projects.


Be sure to visit our store,Streamlined Backshop Services, where you can purchase many great items like DCC Decoders and Command Stations, DCC Installation Parts, Locomotives and Rolling Stock, Ready-To-Run Sound Cars, and our exclusive custom-engineered truck pick-ups.


Be sure to visit our friends at www.hoseeker.netwhere you can find parts lists and diagrams of all your vintage and contemporary locomotives.



ESU LokSound 

73900 Select 21MTC Speaker Wiring


Today, I offer some comments about connecting speakers to the new ESU 73900 LokSound Select NMRA DCC Sound Decoder 21MTC Connector decoder.  

By the way, these comments apply to ESU 54499 LokSound V4.0 NMRA DCC Sound Decoder 21MTC Connector and ESU 64499 LokSound V4.0 M4 Muli-Protocol 21MTC Connector as well.


You will notice the only wires on this decoder are two brown wires for the speaker connection.  Some DCC-Ready locomotive models use internal circuitry on their adapter board to connect to the speaker to the decoder.  This can be referred to as an integral speaker installation.  This is one of the advantages of the 21MTC connector.  Pins 9 and 10 on the integral 21MTC Connector are reserved for speaker connections.


The ESU 73900 LokSound Select NMRA DCC Sound Decoder 21MTC Connector has two ways to connect the speaker.  Pins 9 and 10 on the integral connector and the two brown wires.  The two brown wires are used for an isolated speaker installation only.  They are not required and can be removed when the model incorporates an integral speaker installation.


If, for example (and I won’t say exactly how I learned this), you plug the ESU 73900 LokSound Select NMRA DCC Sound Decoder 21MTC Connector into your ESU 51900 LokTester Decoder Test Set so that you can program it with your ESU 53452 LokProgrammer Set AND you connect the two brown wires to the speaker connection not thinking that the ESU 51900 LokTester Decoder Test Set features an integral speaker installation. 

When the process of loading the sound file is finished, you switch to Cab Driver to test the installation and you get nothing.  A mute sound decoder.  Bummer.  You stare at the whole mess for a few minutes and have another one of those “light bulb moments” when your focus lands on those two brown wires.  

You think out loud, “Oh yeah, I bet that ESU 51900 LokTester Decoder Test Set has an integral speaker installation...”

ESU LokSound 21MTC Connection Diagram



You can purchase many great ESU products today from my online store


Streamlined Backshop Services