As the denon supplied power supply unit is only 65 watts, I would think about getting an in-car inverter so you can plug the existing GO power supply into the car
I would recommend using a power inverter instead. This way you have a regulated voltage being delivered as your engine Tom’s fluctuate. This will also give you a breaker in between to keep from having damaged equipment due to a surge.
I could not find a diagram of the adapter to verify, so I did not want to give it a greenlight. If it is just a step up converter, you run the risk of seeing surges when the alternator is pushing 14-16v and seeing a drop in voltage when the alternator is pushing 12v (you see power lost on the accessory rails).
Get the 19v laptop charger for cars. There are some on amazon with different plugs with more A. I also believe going up and down would be a waster of efficiency.
Stepping down then up or up then down isn’t going to create any issues of sound quality or power surges
If you get the inverter in the car then you can carry on using the original power supply, so you’ve no worries about incorrect polarity or over-voltage or under-ampheres etc
Also when you’re not using the GO in the car you can plug other mains powered devices into the invertor instead.
You don’t want to keep a mains adaptor and a car adaptor for every device you own. Lol
Any update on whether this car charger works for the Go? I’d like to plug my Go into the 12v port on my large batter/solar generator as I cannot charge via solar when I have the AC plugged in (gotta be DC)