The problems with Soundtraxx decoders prior to the Tsunami.


I have numerous DSD-100LCs in my loco fleet, but they have a few problems that Soundtraxx has addressed and are not in the new Tsunami decoders. At the moment (April 07) there are only Steam Tsunamis, no Diesels.


The previous price for the DSD-100LCs were in Australia, were $65. They have been replaced by the DSD-101LC range that has 3 versions, an Alco and two EMDs, 1st and 2nd Generations at A$94. An 8 ohm speaker has to be provided. Steam Tsunamis are A$165.


The “specific” Soundtraxx decoders for example the 090 range are a little more expensive but have the same problems as the DSD-100LC and 101LCs. These are:


·       Low frequency motor control: This causes the motor to buzz/hum and the level of this buzz/hum varies depending on the type of mechanism. Some of my locos, this buzz/hum is tolerable but others, it is so annoying. No matter what value is programmed into CV 9, it does not reduce the buzz/hum significantly. The best value for me is “230” (the highest PWM motor drive frequency. For these locos, I have fitted a second decoder, just for the motor control for example the smaller NCE N14SR or the TCS T1 or M1. This fixes the headlight problem mentioned below and provides better motor control with CV 5 – Volts Max and CV 6 – Volts Mid, that Soundtraxx decoders don’t provide. I am used to fitting two decoders, as I have a few DSX sound only decoders.


·       Cannot operate LED headlights properly:  LEDs do not stay off when selected off, they continually flash. I have fitted the “Tony’s fix” for this if there is no second decoder. This is a little fiddly but works great.


·       Do not remember headlight selection:  Only fix is with second decoder.


·       Most annoying “sound reset” on the slightest hint of dirty track: These can be reduced somewhat by cleaning and minimal lubrication of the mechanism. Too much oil causes intermittent electrical pick up. I use Peco Electrolube here. At the slightest hint of dirt I still get them and others have reported these irritating “sound resets”. Soundtraxx has recommended for the DSX an addition of a external capacitor that is easily soldered to the relevant “pads” but nothing for the DSD-100LCs. For my DSD-100LCs, I have added my own “Stay Alive” capacitor.


Early DCC decoders had the same low PWM frequency motor drive and quickly good the title of “Noisy” decoders,  that these Soundtraxx decoders have. Modellers complained about the buzz/hum that these decoders caused. All later model DCC decoder have what is called by many as “Quiet Drive” etc. See my PWM article.  


I have two DSD-100LC steam decoders, but I find the sound from these not “appealing” (to tinny) but the diesels are “appealing” enough and provide idle sounds that the steam ones don’t. I set all my decoders to turn off the sounds automatically, after 3 minutes of inactivity. I will put one of these steam DSD-100LCs into “Thomas”. The little kids won’t notice the buzz/hum.


Most of my future loco purchases will be coming RTR with SOUND from Eureka Models that will have a QSI chip included for an extra A$100. This saves me buying ANY decoder and speaker and saves heaps of time and money. They will have back EMF and will be quiet.


If fitting steam sound decoders to an existing loco for the first time then there would be no alternative, just fit the Tsunami at A$165 plus speaker. This will give great performance with a back EMF motor control – the ultimate as far as I am concerned.


My preference for sound has changed from one that wanted idling and more prototypical “correct” sounds to one that is just giving each loco a “sound identity”, a diesel hum or a steam chuff. This enables a generic sound decoder, hence the DSD-100LC but I have to put up with noisy non back EMF motor control. This is something that each modeller will have to sort out. But dollars do count. When there is a fleet of sound locos, the ultimate roster, I have got sound into MORE locos for the same expense. Running eventually a timetable operation on my layout, each loco will only be run for 15 – 30 minutes instead of for hours, so even the type layout operation can determine what type of sound.


Alternative decoders  Apr 07:


Diesels: Loksound & maybe soon Soundtraxx Diesel Tsunamis.

Steam:  Soundtraxx Tsunami and Loksound


Note: QSI Solutions (A part of Tony’s Trains) has promised after market decoders for some time now, but still not here. QS Industries are making these sound decoders.