Look on page 4 of the manual. It clearly states 16V AC Max input. This means you can use any power pack that has a 16V AC output or purchase a separate 16V transformer.
If you don't have the manual, go here;
http://www.lenz.com/manuals/accessorydecoders/LS150.pdf
Carey
Keep it between the Rails
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Jerry
Rio Grande vs. Santa Fe.....the battle is over but the glory remains!