# QSI Titan Decoder for Aristo Dash-9: 6 or 10 amp?



## RodSten (Jun 14, 2013)

Hi,

I'm new to the forum and fairly new to G Scale railroading, although I have run HO and O scale for quite some time. I have taken advantage of a lot of great advice offered on this forum and have been able to find answers to most of my questions (Thanks to everyone for your help!), but I haven't found an answer to this one: 

I have a 200 ft ground-level loop with little or no grade in a wooded area of Connecticut. I use a 10 amp NCE DCC system with a Digitrax PS2012 Power supply. I currently run two Aristocraft Dash-9s with QSI Titan 6 amp decoders in consist pulling about 15 stacked intermodal units (about 35 feet). I am going to start running a second train with two more Aristocraft Dash-9s pulling up to 30 feet of freight. Initially the train will also run on the 200 ft. mainline, but I am probably going to build a second internal loop of about 150 ft. I will probably have some questions about powering this larger railroad, but for now my question is this: Are the 6 amp decoders the right ones for the Dash-9s or should I be using the 10 amp decoders? Would the answer be different if I wanted to run 3 or 4 Dash-9s in one consist? What exactly is the difference between the 6 and 10 amp decoders, and under what circumstances would I want to use the 10 amp decoderr?

Thanks!
Rod


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## Jethro J. (Apr 4, 2012)

Rod the 6 amp ones will be fine, I have 18 Dash 9s with the older QSI boards in them and they run fine and I think they are only 3 Amp boards.


J.


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## Greg Elmassian (Jan 3, 2008)

I guess first you need to know the amperage of a Dash 9, which can be 2 amps, up to 3 amps or a bit more in very heavy load situations. 

So clearly even under light load you could not run 4 locos on a 6 amp decoder. 

Due to the poor air circulation in the Dash 9, I would buy the 10 amp version that already comes with a fan. If not, then buy a small 5 volt fan and get the 6 amp version. 

You could use the 10 amp units to power TWO dash 9's permanently coupled. I prefer decoders in all my locos, I don't want any permanent coupling. 

If you do want to save money and couple 2 together permanently, the Titan's dual amplifiers can power one speaker in each loco. 

Greg


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## RodSten (Jun 14, 2013)

I do plan on putting a decoder in each Dash 9. What I was wondering was if I needed a larger decoder for each loco, but it seems that the 6 amp Titan in each loco is enough. 

Thanks J and Greg. 

Rod


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## Greg Elmassian (Jan 3, 2008)

Yes it's enough, but I've had situations with the older QSI's not getting enough cooling in a Dash 9... so try it, and if it overheats than a small $2 fan can be used... 

Don't have that issue in the SD45's or other locos. 

Greg


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## Cougar Rock Rail (Jan 2, 2008)

A friend of mine in our club runs a 12A Massoth system in order to run four big locos and the only decoder that hasn't burned up in his Dash-9's is a Massoth XXL. I would go with the larger decoder if it was me. 
Keith


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## Greg Elmassian (Jan 3, 2008)

Keith the transistors in the QSI are 50 and 60 amp capacity. My reference to fans is that in a dash 9 there is very little venting and heat can build up inside. 

Exactly what decoders did he "burn up"? 

Greg


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## Cougar Rock Rail (Jan 2, 2008)

Heating up in the dash-9's is definitely a problem, you're right. The decoders he burned up were Digitrax and NCE I believe. I think part of the problem is that under constant heavy loads the motors heat up, start drawing more into a vicious cycle... 

Keith


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## Greg Elmassian (Jan 3, 2008)

Interesting, I've not had any significant issues like that, nor have I heard of this issue in dash-9's.... now, there are certain Aristo locos that did have a bad batch of motors (Which Aristo offered replacements for) that did indeed start drawing more and more current, and some would continue until they smoked, but normally this was not a stable condition, i.e. the motors would continue to draw more current over time. 

It would be interesting to know how much current these locos were drawing to see if they were way out of line with most Dash-9's. 

(Also my guess was that your NCE decoder was the free one that came with the NCE set... that is a 4 amp decoder, and an old design, and the digitrax, well, it's really junk, they had a reputation of going bye bye BEFORE I entered large scale!!) 

But we are really derailing this thread, it was which QSI to buy, not a decoder comparision with no holds barred. 

Greg


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