# DCC for Accucraft Big Boy



## pwiegner (Mar 9, 2008)

Hello,
My Accucraft Big Boy is equipped with a Phoenix 2-k-2 sound board but no DCC decoder. The loco rests on a roller bench and draws approx. 1 Amp. when running in analog modus. The manual says nothing about DCC. Any suggestions?

Peter


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## HPC (Jun 18, 2010)

Hello,
we have equipped our Accucraft Big Boys with Zimo MX 66 Decoder. It is easy to install the decoder, but you have to make a change on the sound decoder settings.
best regards
peter


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## Greg Elmassian (Jan 3, 2008)

It might be nice to put 2 decoders in it, to accurately portray the 2 powerplants, and to give the chuffs that go in and out of sync. 

For the value of the loco, I would use 2 of the MX690 decoders, and sell your phoenix to help offset the cost. 

Regards, Greg


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## pwiegner (Mar 9, 2008)

Hello Peter(also?),
how did you manage the installation of the Zimo decoder? Is it necassary to disassemble the tender? How goes the wiring?

Peter


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## Cougar Rock Rail (Jan 2, 2008)

It might be nice to put 2 decoders in it, to accurately portray the 2 powerplants, and to give the chuffs that go in and out of sync. 


You shouldn't need two decoders if you use the Zimo --they probably can handle two pulse inputs for the independant chuffing. Massoth sound decoders definitely have this ability. I agree with Greg to use the Phoenix for something else and put in a sound decoder. 

Keith


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## Greg Elmassian (Jan 3, 2008)

Train-Li, the importer of Zimo, used 2 decoders for the reasons I gave. I was curious also, since the QSI will also do the independent chuffing by BEMF detection. 

Maybe Axel will weigh in here. 

Regards, Greg


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## Cougar Rock Rail (Jan 2, 2008)

Maybe they used two to be on the safe side because of the high current draw from such a big loco?


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## Greg Elmassian (Jan 3, 2008)

I thought Axel stated it to get the 2 distinct prime movers independent. When you use BEMF chuff, not every system can correctly interpret 2 motors in parallel. 

I was under the impression that the Accucraft did not draw nearly as much as the USAT one, for example. 

Paging Axel.... 

Greg


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## Axel Tillmann (Jan 10, 2008)

....... finally the page reached me ....









So OK, here are a few thing to consider.

1. We did the BigBoy of USA Trains. This engine is equipped with two pitman motors which together have a stall current of >5A. In addition there are so many light bulbs installed that this adds another 1.5A and each of the smoke units utilize at peak about 1A.

2. Even if we wouldn't have used for security reasons two independent decoders,t here are a couple of other good reasons to do so. The USA BigBoy has two independent smoke units that with the ZIMO implementation are used to generate chuff synchronized smoke. While SoundDesign has on their schedule a specialized sound decoder to simulate 2 independent chuff origins, that still doesn't solve the problem that we only have one specialized fan output for the chuff synchronized smoke. But each of the smokestacks has to be connected to its own fan control to be only active with the chuff of the respective engine output. So no matter how you slice and dice it, I need two independent decoders for that regulation. Also both smoke units would have overloaded the maximum low voltage output.

3. Until proven otherwise (waiting for that sound project) I believe the "ouot-of-sync bahavior" achieved by two decoders is far more realistic than the simulated one. I have seen the random in and out of sync behavior with two decoders and I am willing to see if the simulation will come close.

4. The sound out of two different amplifiers into two different speakers is so more distinct and clear than all the sound into one single speaker.

So given the fact that the total current could have potentially overheated the decoder, that the implementation seems to be more perfect (two independent smoke unit controls), and the engine cost to sound upgrade ratio justifies to shoot for the top.

One word to the speakers. The speakers that were in the engine were not was their salt. I strongly recommend top notch speakers (and I don't mean Chinese pots). I personally have searched a long time to find great speakers, even for small spaces and I am glad to have found them.

As far as the Accucraft engine. You can't measure your current requirement on roller stands. Put the engine on the track under DC and let it start running. I have a college push the engine down and hold it in place while I increase the power and observe the Amperage - what you get then is the stall current. At startup with lots of cars or up the hill you might get close to stall current. Now count all your light bulbs, firebox if any, etc., + measure the smoke unit now you know what the decoder has to deliver.


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## pwiegner (Mar 9, 2008)

Hello Axel,
due to the size and weight of the Accucraft Big Boy I will leave it on roller stands as a static display. So the the current will not excede 1 to 1.5 amps. I will try a ZIMO decoder or an ESU LokSound XL which gives the possibility to modify the chuff by CV settings.

Peter


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## Axel Tillmann (Jan 10, 2008)

Peter:

ZIMO also offer chuff influence via CV settings:

CV 267: Chuff sound Frequency if you uze the technique of "virtual cam sensor"
CV 268: switching between real and virtual cam sensor
CV 269: Accentuating the lead chuff (Beyond what might be already in the sound sample itself
CV 270: Future for very slow movement - not yet implemented) 
CV 271: Manipulating the fast speed chuffs which helps to keep the sounds more distinct if desired (less portotypical but sometimes more wanted in our model world)
CV 275-277 Loundness control of chuff beats (various adjustments)

A large variety of ajustments.


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## HPC (Jun 18, 2010)

Hello Peter,
sorry, but I have read your question today. First apologize if my englisch is not always correct. We are here in Gemany 4 guys with Accucraft Big Boys. In my engine I am using a Zimo 690 Sounddecoder, the other one has an Phönox Big Sound 2K2 sound decoder as yours. We are using ZIMO MX1 multi protokoll .


Installation Zimo 690 Soundecoder

This is a **** of work. I have changed all light to 16V mini lamps. The Zimo sound for the Big Boy is not as good as the Phönix sound. My own Big Boy was modifed this way. But this is not my favorite solution.


Phönix Big Sound with Zimo MX 69


First a remark. In this version you have 2 decoder in the engine with differend DCC adresses. Depending on your DCC you must change between the 2 adresses. The zimo adress is for driving the engine, the other is for the Phoenix Big Sound with all the sounds.

Yes you should disassemble the tender. As far as I remember there are 6 screws. The reason for that is, that you can not reach the Phönix Big Sound through the opening of the coal imitation. The access to all components is much easier if you disaasemble the tender. In the Phoenix handbook on side 15 is a very simple wiring diagramm for DCC. Motor and track should be connected on 4 pole green terminal block of the Zimo MX 69. The phoenix Big Sound must be connected with the track additional. *When we have done this, we have had no sound.
*

Additional you have to change the set up of the Big Sound. Ours was configured for DC. You have to change this now to DCC. We have used the Phoenix computer interface to change the settings.

Additional remarks:

One Zimo MX 69 or MX 690 is more than enough for the Big Boy. There is no power problem even with very long trains.! 
Both solutions are not really state of the art. The smoke generator is poor. There are much better solutions described in the Mobazi forum.


I hope this was a little helpful.

best regards
Peter


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