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USA DCC Standard


RDS

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Whilst out in America recently and because I don't have any particular type of Locomotive, just something that I like the look of on my layout, I bought a (new) American GP40 Diesel, DCC fitted.

 

The Loco was set to id3, the same as the UK and I was able to change the id to my preferred value of 40, using my Elite.

 

Although the Loco runs very well and the lights, both cab and exterior work perfectly, it does emit a rather strange (buzzing?) when it runs.  This is very consistent both forward and reverse and it is also consistent in that it starts the noise when any throttle is applied and before the Loco has actually moved.  I even wondered at one stage if it had some form of sound fitted!

 

So, my question: Is USA DCC compatible with UK DCC.

 

 

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All DCC is to the US NMRA (National Model Railway Association) standard, no matter where the decoders and controllers originate, so there should be no compatibility issues.

 

The DCC power applied to the motor is a square wave of around 10kHz at full voltage with a varying mark space ratio meaning the average value goes from 0 to 15 corresponding to stop and flat out at the limits.  Almost certainly what you are hearing is the motor buzzing at the 10kHz.

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I wouldn't think so.  There is some variation in the DCC frequency depending on your decoder, and maybe your motor has a resonance at around your decoder's frequency.  So a possible cure would be to change decoder brands, no guarantee though.  Conversion to DC using DC power would be the only foolproof cure.

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Hi John.  That's interesting.  Mine is a Bachmann.  Are you suggesting it is a design feature and meant to be like that.  I asked the dealer to run it on his layout in the shop.  He only had a DC layout and it wasn't too quiet in the shop, so I did not hear anything that sounded wrong.  Fishy says running on DC would cure it, so maybe it is just a DCC related 'feature'.  In a way I am glad I didn't suspect anything was wrong with it, otherwise I would not be able to look at it and remember our time in the model shop in York, Maine.  I posted a picture of the sign outside the shop in the 'what's your latest aquisition' thread, around the middle of September.

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RDS, i have a pair of Bachmanns, GP 30, and another in red. They both whine and grumble at low speed, but you notice it less when they speed up . I dont think DC will cure them, it hasnt on mine.. My red one might be a 40, i will look when next up. .None of mine have had more than 60 mins use, on continued running, so that might be something to try. I like it, reminds me very much of american trains,. We have been across 6 times, and my lad, works for apple in Austin. It did not occur to me to buy any locos, when i was there, far too busy, fly fishing, and buying new fly rods. I fished with the indian tribes, on their reservations. brilliant. john

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I have an American HO gauge Bachmann Union Pacific DD40AX Centennial with sound and haven't experienced the buzzing you describe although there is no F number sound function- the sound activates as soon as the address code is selected although the lights are controlled by F numbers.My only issue with the loco - doubtless due to it's length- is that as the loco turns on the outer third radius  the side steps just brush the raised part on the power track which was corrected by filing a fraction of a mm off the side of the rear side steps.Roy 

 

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... the sound activates as soon as the address code is selected although the lights are controlled by F numbers ... 

 

That seems (I nearly put sounds) like mine although the 'sound' only starts when my Elite control is rotated slightly but before the Loco starts to move. The lights are controlled using the normal F0 and F1 functions.

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