The Monkey Posted October 24, 2010 Report Share Posted October 24, 2010 I have a powered USB hub that I'd like to get up and running. However I don't have the wallwart for it. The input is marked DC 7.5V 2.1A. If I can't located the original wall wart, what rating range would be acceptable to use with this thing? Or does it have to be specifically 7.5V 2.1A? Quote Link to comment Share on other sites More sharing options...
Fitz Posted October 24, 2010 Report Share Posted October 24, 2010 You'll need to replace it with a 7.5VDC wallwart with a current rating 2.1A or greater, so 2.5A, 3A, etc will be fine. It'll probably be cheaper/easier to just pick up a new USB hub though. Quote Link to comment Share on other sites More sharing options...
cetoole Posted October 24, 2010 Report Share Posted October 24, 2010 You also need the right connector and polarity. Quote Link to comment Share on other sites More sharing options...
The Monkey Posted October 24, 2010 Author Report Share Posted October 24, 2010 Yeah, I plan to get a new hub, but I'm at my parents' place in East Hampton and will get gouged. Would a 9V wall wart be a bad thing? I basically don't understand how these numbers work... By the way, the unpowered HRT Music Streamer is a piece of shit because it basically needs to be run from a powered USB hub. Fuckers. Quote Link to comment Share on other sites More sharing options...
Fitz Posted October 24, 2010 Report Share Posted October 24, 2010 Depends on the equipment, some stuff can tolerate a bit higher voltage, some stuff will say fuck you and go bye bye. Quote Link to comment Share on other sites More sharing options...
cetoole Posted October 24, 2010 Report Share Posted October 24, 2010 9v might work, or might blow it, depends on the hub. I wouldn't risk it. Quote Link to comment Share on other sites More sharing options...
The Monkey Posted October 24, 2010 Author Report Share Posted October 24, 2010 fucking electricity. Thanks guys. Much appreciated, as always. Quote Link to comment Share on other sites More sharing options...
dsavitsk Posted October 24, 2010 Report Share Posted October 24, 2010 I wouldn't risk it. I would -- if you don't risk it, you don't have a working hub. If you do, you might. But, I wouldn't risk it if you are not in the room in case is burns up Quote Link to comment Share on other sites More sharing options...
cetoole Posted October 24, 2010 Report Share Posted October 24, 2010 I would -- if you don't risk it, you don't have a working hub. If you do, you might. But, I wouldn't risk it if you are not in the room in case is burns up Less worried about the hub, and more about worst case and the computer. Quote Link to comment Share on other sites More sharing options...
mrarroyo Posted October 24, 2010 Report Share Posted October 24, 2010 If you have a Radio Shack close by you may be in luck, check out: Enercell High-Power AC Adapter : AC Adapters | RadioShack.com However at the $37 cost a new hub would be a better deal, good luck. Quote Link to comment Share on other sites More sharing options...
n_maher Posted October 24, 2010 Report Share Posted October 24, 2010 I'd probably try a 6V unit before I tried a 9V one. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted October 24, 2010 Report Share Posted October 24, 2010 you know that the usb output voltage is 5 volts, so likely the power supply inside the hub is a simple ldo linear regulator. Which means it probably won't work at 6 volts, and it might overheat at 9 volts if you are going to pull full power out of it. Quote Link to comment Share on other sites More sharing options...
n_maher Posted October 24, 2010 Report Share Posted October 24, 2010 you know that the usb output voltage is 5 volts, so likely the power supply inside the hub is a simple ldo linear regulator. Which means it probably won't work at 6 volts, and it might overheat at 9 volts if you are going to pull full power out of it. My thinking was that just about any wallwart Dinny is likely to find laying around won't be regulated or exactly 2.1A. So odds are good that any 6V unit is probably pushing over 7V already and I'd rather undershoot than overshoot. If it's a simple LDO on the inside the worst case by feeding it too little voltage is that you get poor to no regulation and perhaps low voltage at the output, right? The consequences of too much V on the input seem much worse (burnout). Quote Link to comment Share on other sites More sharing options...
The Monkey Posted October 25, 2010 Author Report Share Posted October 25, 2010 Thanks for your help, gang. I ended up getting a new hub. But it really is a pain in the ass when you misplace a wallwart, isn't it? Based on this thread, it seems like you really need to replace it with the same voltage rating, but can go with higher current rating, is that a fair summary? Quote Link to comment Share on other sites More sharing options...
spritzer Posted October 25, 2010 Report Share Posted October 25, 2010 The component will only use as much current as it needs but higher voltage can overload internal parts. The rub here though is that if you have a say 12V/1.5A wallwart but the component draws only 300mA then the voltage the wallwart outputs will be higher than the rated 12V. The voltage output is at the rated current draw so it rises with less current demand. Quote Link to comment Share on other sites More sharing options...
The Monkey Posted October 25, 2010 Author Report Share Posted October 25, 2010 Ah, that make sense now. Thanks for the clarification. Quote Link to comment Share on other sites More sharing options...
spritzer Posted October 25, 2010 Report Share Posted October 25, 2010 Happy to help. Quote Link to comment Share on other sites More sharing options...
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