Recommendation Wanted for DC step-up transformer

All:

Background:

I have acquired a brand new MTH PS1 fan-driven smoke unit (part # AA0000011).  The original thought was to drive it with my Mean Well LRS-150-12 (Input: 120 VAC  Output: 12 VDC, 12.5 A) power supply.  I have determined that 12VDC isn't quite enough power to make it smoke (fan does run).  I was able to get to function correctly at 15 VAC (it will run on A/C or D/C).

Question(s):

1. Can anyone recommend a DC step-up transformer to get 12VDC to 15VDC (or an adjustable value)?
2. My preferred solution is to use a transformer rather than another power supply to do this.  I will be driving (eventually) up to 4 such smoke units.  Any problems with this approach?
3. Is there a better way to do this?

Thank you!

George