Posting here for a sanity check. I am just beginning to plan my wiring for Menards and Woodland Scenics building lighting. I bought one LM2596 AC/DC to DC Buck Converter and one Woodland Scenics Light Hub to experiment on how each DC power regulator controls DC power under varying building light loads.
My initial checks with digital voltmeter using transformer 15v AC accessory power, show that the LM2596 maintains near-constant DC voltage as I increase DC power load when adding additional building lights after initially setting the DC voltage output ... DC output holds very steady under varying lighting loads. Whereas, using the Woodland Scenics Light Hub with one of the four outputs, the DC voltage output decreases as I increase DC power load by adding additional building lights after initially setting the DC voltage output ... DC output varies under varying lighting loads.
So, it appears that the Woodland Scenics Light Hub is not a regulated power converter. It also appears that the LM2596 is a good regulated power converter. So, if I want to maintain a constant, say 4.5v DC, to a specific light bus in my layout where I add or remove loads occasionally, I should use an LM2596 which will maintain a constant DC output voltage as I add or remove building lighting on that bus. Whereas, if I were to use a Woodland Scenics Light Hub to power a specific lighting bus for a group of buildings and initially set the output DC voltage to say 4.5v DC, then when I might add or remove lighting in that group of buildings, then the WS Light Hub DC output voltage would increase if I removed a light load and would decrease if I added a light load.
Same scenario if I want to maintain say, 8v DC for a different group of buildings with other LED lighting specs. The LM2596 would maintain a near-constant DC output voltage once initially set while the WS Light Hub output DC voltage would vary with changing lighting loads in that group of buildings.
So, appears that I should go with more LM2596s vice more WS Light Hubs for my layout building lighting groups if I want to maintain constant DC voltage regardless of add/removing building lighting. I also understand that many LEDs generally tolerate some variance in voltage even when spec'd at a specific voltage so some variance in DC output is likely ok. One type of lighting that apparently doesn't tolerate DC voltage variations appears to be Menards flashing window signs and also Miller Engineering billboards and window signs that are spec'd at 4.5v DC so including them in a bus served by a LM2596 is what I'll do. I may use the WS Light Hub that I already have for a cluster of only WS buildings. But, if/when I expand my lighting needs, I'll opt for more LM2596s for regulating DC voltage to the added lighting buses since I can 1) vary the output voltage with its included output voltage adjusting screw and 2) maintain that voltage in a lighting bus even after add/deleting building lighting loads ... win-win.