JD, do you see any issues with using a 16V cap, being so close to the 12-14 volts N DCC layouts tend to run? And, do you ever add the in-rush circuit (100 ohm resistor + 1N4007 diode in parallel) that ESU shows on their diagrams?
1. I keep my track voltage for N scale at about 12v (it is adjustable with an internal pot on the Digitrax Chief and other Digitrax boosters), so I don't worry about the 16v caps. I've run my engines fine on layouts with a Digitrax system set on the "HO" setting, which puts out around 14v to the track and never had a problem. In fact, I just got back from a 2-day NTrak setup at our local library, where I ran my sound-equipped steam and diesel locos for two days straight with a Digitrax Chief set on the HO setting (I didn't realize that's what it was set on until the end of the show). I did have one tantalum cap blow up on me a couple of years ago, but I'm sure that was because the cap itself was defective, not because of the voltage applied to the track. That said, I would be wary of using 16v caps if the track voltage were above 14v; a 10% "cushion" seems useful. 12v would be better, and most DCC systems have some way to reduce the voltage output to the track.
2. I don't use the diode/resistor when I install 440uf of capacitance - it's not enough to cause a "fake" short at the command station. In fact, in my engine terminal, I have literally 20 engines sitting, 14 of them with ESU LokSound decoders. You would think that when I turn on the layout there would be this huge rush of current into these locos, causing problems, but it doesn't happen. If you were to use really large capacitors (e.g., 1 farad), then the resistor/diode protection might be necessary, but I've not found it necessary with my installations (and note that the diagram in the ESU manual that shows the resistor/diode protection also shows a 2200 uf cap, which is about 5 times more than what I use in a single locomotive).
John C.
