Thanks guys! I can see that there are many options.
I need one for a dehumidifier that comes with a 9V 2.5A ac adapter. The cap inside bursted. It was running 24/7. Maybe that was why. The power brick ran quite hot drawing 2+ amp.
The cost is the primary factor. Buying from Mouser may not be possible. The ac adapter is like $20 plus another $10 for shipping. That is $30+ expense. I can save the shipping if I add up $25 buck from Amazon.
I also agree that the one with a dial is not idea.
Amazon also has a bigger one with the selector. Is a longer one better than the small one?
The dial or the selector is just there for changing the resistance to the switching circuit. Correct?
Ok that clarifies - you want a 9V
DC output mains adapter with a minimum output current of 2.5A.
I would definitely go for one without a voltage selector for the reasons previously discussed. (the knob adjusts regulated output voltage, not resistance btw). I would also go for a rectangular laptop style rater than a 'wall wart' due to the weight - particularly with US outlets.
If you want it to run cooler and with longer life then there's no harm in going for one with a higher current capability, for instance, 5A.
P.S. Double check that the output connector polarity is correct (centre +ve etc). It's easy to screw up with those multi-plug kits.