I'm setting up a new layout and wonder if anyone can help me with a question about the DC Master. I'm about to start the layout wiring but need to make sure this will work. I have a BLI SD40-2 with DC Master sound control and a Tech 4 260 transformer. I plan to run a bus wire around my layout and stub feeders down from the track to make the connections around the track. My question is will this cause a problem with the DC Master? They say to run the variable DC from the transformer to the DC Master unit and then run the red wires from the unit to the track. I cant really make the red wires the bus wire because they are such a small gauge. Will it still work if I connect the DC master to a part of the track but in all the other spots have the feeders that are connected to the main bus and then directly to the DC power pack? There are no insulation sections that I will be dealing with (on this section at least). Thanks for any help!
If you want to be able to control the sound at any point on the layout, then the DC Master has to go between the power pack and the rest of the layout. Short sections of thinner wire will not cause a problem. COnnect the output of the power pack to the DC Master, and connect the red wires from the DC Master to the bus. You can shorten the wires but that might void the warranty. The short sections of thinner wire won't hurt anythign though.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
thanks for the reply! Just to make sure I got it right, would it be ok to hook the DC master to the transformer, then run the red wires to a terminal block. From the terminal block, I would then run a 16 or 14 GA wire for the bus around the layout? I'm just trying to get the best way to get from the DC master small gauge wire to the appropriate bus wire without losing sound around the layout. Also would doing it this way make using a 14 or 16 GA bus from the terminal block pointless since the gauge of the DC Master wires is so small? Thanks again for your help.
Yes, that's the way to do it.
It would be pointless if our model trains drew tens or hundreds of amps - the thing wire couldn't posisbly handle it. But the main issue with using long runs of too small a wire with model trains is the voltage drop, not the overall maximum current the wire can carry safely. A pair of locos drawing 1 amp will experience a noticeable slowdown if you pwoer them through 50 feet of #22 wire (that's 100 total feet of wire, complete circuit - 50 out and 50 back at the furthest point). However, a SHORT section of thinner wire will not have a noticeable voltage drop - you can;t really solder #14 wire to the track for feeders, you have to use smaller wire, but in short lengths and then connect it to the heavier wiere for the long haul. This is the same thing - the short bit of wire attached to the DC Master won't cause your trains to slow down, and there's certainly no danger of it melting from too high a current load. If you ran wire the same size as that red wire for EVERYTHING, you might have issues.
Voltage drop in the wire is a function of both the size of the wire AND how long it is, as well as how much current is flowing through it. With around 1 amp flowing, even #20 or #22 wire is going to need more than a few inches to drop half a volt or more, so it's perfectly alright to use the thinner wire for short connections.
thank you again for the info!!! My thinking was just what you pointed out.....I thought the amperage on that skinny gauge wire would cause issues going from a very small gauge to a larger gauge and didn't realize it was just a voltage drop concern. Now that I have all my worries settled, I'll go finish working on trying to figure out how to hold the 20 ga wire to the track and solder it at the same time. Not going well so far. still on the practice piece after 2 hours. either i melt the tie, get solder on the top of the rail or drop the feeder before I can get it hot enough to take the solder. Thank you very much for your info.
Rick