So, since it seems that overwhelmingly it is NOT recommended to put two power supplies together to make 14 VDC, then here are some other ideas & questions.
1. It seems from other posts I have read that Digitrax stopped using the PS12 because of unreliability issues with modules powered by 12VDC. I wonder if readily available 12VDC transformers was also part of the reason to switch and 14VDS transformers are very scarce? Will 12VDC transformers still work?
2. If the same modules that ran under 12VDC will also run (better?) with 14VDC, then what about using a 15VDC transformer. These are much more available at my local computer recycle store for $1.00 each. I'm not talking about "wall warts" but rather large 1500mA regulated class 2 transformers made by Labtec.
3. What are the limits for input voltage for the UR92, PR3, PM42, DS64 etc? I don't currently own all these, but would like to if I can afford them, rather than the PS14s needed for each at $12.95 a piece.
Capt. Brigg FranklinUSCG Licensed Marine OfficerCertified crazy train chaserCEO: Pacific Cascade Railway
Lots of 14VDC supplies avaialble, check on eBay, there's one meant for some brand of LCD, about $7 for a (I think) 1.5 amp one. Including shipping to the US - actualyl the one I bought ships FROM the US, not China.
12V is still valid for most DIgitrax accessories. The problem is mainly the Loconet Repeater - I can sort of see why, too. The circuitry uses some voltage perhaps leaving less than 12V, and with the track feeds coming in via the Railsync lines via the diodes on a UP, it could very well that this voltage would be higher than that coming from the LNRP meaning the LNRP would nto be foing anythign in terms of isolating the power supply, half defeating the purpose.
15 is usually ok too, check the device specifications. You also do not need 1 power suppyl per device, like devices cna usually be connected together. For example, a whole string of UP's run off one supply - which is exactly what I'm doign with the 14V one I have, running a power bus and tapping off with coax connectors at each UP5 location. You cna also power multiple DS64's from a single power supply. There's a diagram int he file ssetion of the Digitrax group on Yahoo that shows several options and explains why some are better than others.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Brigg,
The LocoNet Repeater and the PR-3(and maybe the UR92 Duplex wireless unit) are the only Loconet items that really benefit from the higher voltage. I have 5 UP5's, a UR91, & a PM42 all powered with PS12 units. What we are talking about is NOT train power - just the above mentioned Loconet devices.
You can get virtually 'identical' wall wart power supplies off the Internet if you look around - They just do not have a Digitrax logo on them. Building your own with a case, connectors/cord usually runs you more than the discounted price of the Digitrax ones. I bought mine that powers my PR-3 for about $9 at a train show last winter. As for going to 15 volts - more is not always better!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Here's a little info about the evolution of the Digitrax PS14.
At the National N scale Convention held in Louisville in 2008, we built the largest NTRAK layout ever assembled - 50,000 square feet of layout. The main line was powered by Digitrax DCC. The LNRP was the key to the success of this layout. Until then, LNRP had never been tested on something this big and PS12 worked just fine. I don't have all the figures but did see at least two 1000 foot spools of flat satin used during set up. That doesn't include cables that were brought in by attending clubs.
There were 16 LNRP's protecting the loconet on 8 large loops. Two per loop. On initial power up, there was a fault indicated on every LNRP. Since A.J.Ireland and several of his technicians were on site providing technical assistance, he set out to rectify the problem. AJ concluded that the recommended PS12 power supply for LNRP was not enough voltage to handle the large load. He thought that 14 volts+ would clear things up. Of course, the PS14 didn't exist, so the local Radio Shacks were raided for the closest thing to it. They had a 15 volt, 1 amp power supply in stock. After installing those to power the 16 main LNRP's, the fault cleared. We had a successful convention and Digitrax updated the power recommendation for LNRP and subsequently introduced the PS14. PS12 was dropped because as always, Digitrax products will work with a range of power supplies. 12 volts being the minimum. I'll also add that I had three LNRP's installed down line from the main 16. These three performed flawlessly on their lower loaded sections using PS12's.
So after this long explanation, yes other power supplies will work. I run BANTRAK's 7 PM42's with a 16 volt, 20 amp DC power supply. Appropriate fusing is installed. Three LNRP's are powered by 15 volt supplies. (PS14 didn't exist yet) Our UP5's and UR91's are still powered with the PS12's we purchased 7 years ago. Our single new PS14 is powering a new UR92.
Martin Myers
Most large transformers I find say either XX-VAC or XX-VDC but some smaller power supplies have the output voltage with a line ( ---- ) with dashes (- - - ) under the line. Does this represent unregulated DC or some other form of voltage?
A solid line with a dashed lien under it is DC. A single sine wave is AC, a flat line with a sine under it indicates both AC and DC output.
No indication or regualted vs unregulated.
Here's an exam,ple of the 14V 3A power supply I bought. These are suitable for powering multiple DIgitrax accessory devices, with considerations previously mentioned, such as multipel circuits each with its own fuse, and a few devices to not mix with others.
http://cgi.ebay.com/14V-AC-DC-power-adapter-supply-Samsung-170MP-LCD-/330428294427?pt=Laptop_Adapters_Chargers&hash=item4cef0fa51b
I cut the plug off mine as soon as I got it but I THINK it's the right size and polarity for the PR3, My PR3 came with a PS14 and it works fine, even reading Tsunami deocders, so I didn;t bother swapping it out.