# Sound Only Decoder



## ScottyB (Jan 14, 2008)

Gentlemen,

I have a Bachmann Mogul with a Digitrax large scale decoder in it. Been working great for years. Now I want to add sound. Because of the way the loco is wired, I figure the easiest way to do this is to add a second decoder for "sound only" in the tender. After all, there are two track leads already there.


So here's the question: Since I am going to use the new decoder for sound only, and not motor functions, does it matter what the stall rating is on the decoder? I have a Tsunami Light Steam from my HO days that I think would work perfect (with a larger speaker of course) - and it is rated up to 27v track voltage. I know the motor is only 1 amp, but I won't be using that part of the decoder.


I figure just hook up the track leads and walla - sound! Both decoders could be programmed for the same road #, and isolation for programming is easy since one is in the loco and one is in the tender.


Logical? Or am I going to blow this decoder up?


Thanks,

Scott


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## Bill Swindell (Jan 2, 2008)

I think you are correct in every aspect. I have heard that you need to hook up a load to the motor leads on the Tsunami. If you use a DSX or a Phoenix P-5 then they are sound only so they are simple.


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## Road Foreman (Jan 2, 2008)

Scott, 

Digitrax makes the Soundbug as a stand alone sound decoder.. If you use the Tsunami I would follow Bill's advise.. 

BulletBob


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## ScottyB (Jan 14, 2008)

Thanks, 

I'll try the Tsunami and see how that goes. I found a page on Litchfield's site (http://www.litchfieldstation.com/DCC-University/FaqTsunami.htm) about needing to put a resistor across the motor leads. 

If it doesn't work, then I'll just use it for my On30 2-8-0 that really needs some sound! 

Thanks everyone, 
Scott


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## George Schreyer (Jan 16, 2009)

The Tsunami will probably work even if you have to add a resistor to the motor leads to give it some load. However, if it has BEMF, turn that off. Without a motor attached, there will be no BEMF and the decoder may go nuts trying to find some. 

The Tsunami is somewhat limited in sound power, as is the DSX. If this doesn't work for you, then you MAY be better off getting a QSI decoder for the motor and sound and using the Digitrax decoder elsewere.


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## mapper65 (Feb 15, 2009)

I think you will be fine doing it this way. I have an On30 Street Car that I used two decoders in. Used one decoder for motor functions and I installed a sound only decoder for sound. I have a Bachmann Large Scale 4-4-0 that I plan on doing the same thing with. I will be using a Digitrax decoder for motor and lighting functions and at this point I think I'm going to use a Tsunami 1000 in the tender for sound. I don't see any reason what that will not work. Like George said, you may have to add a resistor to the motor leads of the sound decoder but that will remain to be seen. Here is the On30 trolley:

http://www.youtube.com/watch?v=VOislSp9t5Y


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## Trains West (Oct 4, 2008)

you only need to add a load to the motor leads if you want to read back cv's

we have put them in n-scale cars with no load and they do just fine


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