The advent of new SoundTraxx Tsunami-2 and ESU Loksound V5 DCC sound decoders have changed how modelers can use their DCC system's Program Track. A little background regarding the use of the Program Track is in order:

When DCC first came out, part of the spec was for the programming track (service mode). Since it was expected that locomotives would need to have decoders added and there was a high probability of wiring errors, the spec limits the current on the program track to 250mA to prevent decoder damage in the instance of a wiring error. Most command stations met this requirement by simply using a series resistor to limit the current. This worked quite well until sound decoders came out. Sound decoders generally have quite large input capacitors to store energy so that the sound will not be affected by short power losses to dirt, frogs, etc. The problem was that the sound decoders could not draw enough current through the series resistor to charge the input capacitor in time to meet the programming requirements. Enter the Power Pax. The Power Pax uses a circuit breaker to limit the current to less than 250mA, but allows up to 250 mA to quickly charge the input capacitors on sound decoders. The Power Pax does not provide any programming signal, it simply repeats the programming signal produced by the programming track, but at a higher available current than the standard programming track. As you may know, that has worked well for nearly 20 years.

Enter the newest generation of Tsunami-2 and Loksound V5 decoders.

  • Neither the Tsunami-2 or Loksound V5 should be used with a program track booster [such as the Power Pax or SoundTraxx PTB-100]
  • We tested all versions of SoundTraxx Tsunami-2 and ESU Loksound V5 decoders using a NCE PH-Pro 5 amp system & Digitrax DCS210
  • We were able to successfully read & program all addresses [short & long]
  • We were able to successfully read & program all cv values

So the bottom line is the Power Pax and/or PTB-100 may work with whatever older sound decoders you have so far, but the newer more complex sound decoders may need their own programmer [or none at all]. That's why we recommend the NCE Power Cab. You can use it as a normal throttle on the layout, but also use it for service mode to program and read back CV values. To the best of our knowledge, the Power Cab has modified its timing so that it will work with the various new decoders that won't work with the original service mode, and of course it has 1.5 amp capability to charge and power up any sound decoder.