Massoth DCC Decoders - Can Analog/PWM Be Used?

LGB333

LGB333

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Hi Folks - A customer asked me whether the Massoth DCC Sound and Driving Decoders can be used with DC Analog and PWC mode. I've sent a message to the Massoth Hotline asking the question but they've been a little slow responding during the Flu-19 Virus. Anyone know whether PWC can be used with the Massoth decoders, or any DCC decoder for that matter?

Thanks!
Tom
 
Hi Tom,

*most* modern decoders will cope with PWM power, these days..

But, many Manufacturers will say 'no' to cover themselves.. - What tended to happen, was that the PWM frequency component was detected by the decoder, and it attempted to interpret this 'signal' as commands, which led to strange results.

Of course, it is only when things go wrong, that people shout about it. So you will find stories (but how many are first-hand?) of decoders being fried, shed's burning down, and planes falling from the sky! ;)


I personally have run Massoth decoder-equipped trains, on PWM-powered track, without problems. - At least one of these tracks, those in charge had no idea it was PWM power they were using! :rolleyes:

I have not had / seen a problem.. I have had one loco, come to me for diagnosis / repair, where the owner suspected that it had failed due to track-power on a track he visited was PWM. - Though, when quizzed, there had been a collision, derailment, and 8Amps going 'somewhere' for a couple of minutes.
The input rectifier diodes (on the decoder) had 'let-go'.. I replaced these, and the loco / decoder were fine.

As they say: "Your mileage may vary."
PhilP.
(Gauntlet's on.. Fire away, Guys!)
 
PhilP said:
Hi Tom,

*most* modern decoders will cope with PWM power, these days..

But, many Manufacturers will say 'no' to cover themselves.. - What tended to happen, was that the PWM frequency component was detected by the decoder, and it attempted to interpret this 'signal' as commands, which led to strange results.

Of course, it is only when things go wrong, that people shout about it. So you will find stories (but how many are first-hand?) of decoders being fried, shed's burning down, and planes falling from the sky! ;)


I personally have run Massoth decoder-equipped trains, on PWM-powered track, without problems. - At least one of these tracks, those in charge had no idea it was PWM power they were using! :rolleyes:

I have not had / seen a problem.. I have had one loco, come to me for diagnosis / repair, where the owner suspected that it had failed due to track-power on a track he visited was PWM. - Though, when quizzed, there had been a collision, derailment, and 8Amps going 'somewhere' for a couple of minutes.
The input rectifier diodes (on the decoder) had 'let-go'.. I replaced these, and the loco / decoder were fine.

As they say: "Your mileage may vary."
PhilP.
(Gauntlet's on.. Fire away, Guys!)
Click to expand...
Thanks PhilP for your experience. I'm tempted to tell the person that it should be okay to run the decoder on Analog PWM. I'll also post what Massoth tells me.
 
I know the Marklin LGB decoders do not like analogue PWM, pretty sure my Massoth XLS do not either. You can get a filter from G scale Graphics that will remove PWM from an analogue DC signal. I think its about $20. I have one wired to a DPDT switch so I can provide PWM or linear DC depending if the locos have decoders or not.
 
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Greg Elmassian said:
I have seen decoders go crazy on DC PWM, since they my try to interpret it as DCC.

The best thing to do is as Tony recommends, a single PWM to Linear filter on the output of your PWM controller. Cheap insurance and better running.

Greg
Click to expand...

Wow - Thank you for all the comments about PWM and using an inexpensive filter device. Much appreciated!
 
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