1. One other problem can happen with the wattage rating of the power supply. 2. Wattage ratings, for example, depend on several variables. 3. Also, transformers have a maximum wattage rating-a small one might be 50W or 100W, check the label. 4. :Hopefully the device either has a wattage rating or amperage rating written on / engraved in it. 5. The charger doesn't give wattage rating but I sincerely doubt it runs 250 watts an hour charging all four slots. 6. :Would you by any chance know the power rating ( wattage rating ) of your amp, and of your speakers? 7. The power supply has a wattage rating on the side : make sure the new PSU has a wattage rating at least as high. 8. The power supply has a wattage rating on the side : make sure the new PSU has a wattage rating at least as high. 9. :You can determine the wattage rating of a microwave by how long it takes to bring a fixed amount of water ( usually 2 cups or 500ml ) to a boil. 10. The purpose of the Vintage 30 was to create a speaker that sounded similiar to a Celestion Alnico Blue, but have a higher wattage rating, as apposed to the Alnico Blue which had 15 watts RMS handling.