I did testing using an older Bachman Spectrum linear transformer, Aristo-Craft PWC Transformer, PWC Motor Controller from Amazon and two different generations of the Revolution Trackside Base Station. I found that everything but the Bachmann Spectrum linear transformer caused issues with the headlights but you can get a PWM to linear adapter to put between your transformer and the track to correct this issue.
I do want to point out this issue isn’t something new or specific to the Dash 9. Other manufactures have had issues with PWC/PWM over the years as well. This is an issue that a lot of people won’t see but for the ones that do I hope this info helps them as there is a solution to it.
To see the full details of my testing and solution check out the video HERE.