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geekhack Community => Other Geeky Stuff => Topic started by: nowsharing on Fri, 09 October 2009, 13:03:07
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I have a pair of Creative Gigaworks T20 speakers that arrived with a defective AC adapter. I can't find a stock replacement online, but I think it may be possible to use a generic adapter, or perhaps one from a laptop to power them?
My netbook's ac adapter has very similar specs, but a different tip. Would buying an extra and swapping the tip work?
The specs on the speaker's ac adapter read as follows:
Input: 100-240VAC~50/60Hz 1.2A MAX
Output: 15V---2.5A
Efficiency Level IV 115V
I read here (http://www.head-fi.org/forums/f21/ac-adapter-use-gigaworks-t20-424085/) that the speakers are rated 2.9A, but I don't really know what any of this info means to be honest. I'd hate to use something I'm unsure of and ruin the speakers.
If anyone could point me in the direction of an adapter that would work, I'd really appreciate it.
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What you want is an AC to DC adaptor, that does 15v, and (going on the 2.9A assumptiomn) 3A. Having more current available is not a bad thing (Less is), but the voltage (generally speaking), must be the same. You *may* be able to get away with .5v either side, but 15v is fairly common for, say, a Universal Laptop AC adaptor. These will generally be capable of at least 3A, (90W).
Most will come with a variety of tips that fit on the end. if one of these will not fit, you can take the 2.5mm tip included in just about everything, and make up a short flylead using the tip off the deceased Adaptor.
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Thanks so much InSanCan and Ripster! I spent many hours searching for the info you've provided me with; I wish I'd just come here to begin with.
A final question before I place an order: If you had to choose between a universal adapter (advantage is the included tip set), or a laptop adapter rated at 5A/15V (who's advantage is a better looking build quality), which would you choose?
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Are the speakers marked as to polarity? Some adapters are tip positive and some are tip negative for the plug, but the replaceable-tip adapters can be reversed I believe.
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Another detail I've overlooked, thanks for the additional info SCTony! The laptop-specific adapters don't seem to list the tip polarity as a rule, so I will definitely be getting the universal adapter.
I truly appreciate everyone's help with this, thanks again!
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What you want is an AC to DC adaptor, that does 15v, and (going on the 2.9A assumptiomn) 3A. Having more current available is not a bad thing (Less is), but the voltage (generally speaking), must be the same. You *may* be able to get away with .5v either side, but 15v is fairly common for, say, a Universal Laptop AC adaptor. These will generally be capable of at least 3A, (90W).
You have to be a bit careful about this around non-switching adapters. Most of the non-switching type wall warts are also unregulated. They are designed to put out the rated voltage at the rated current, and can typically put up to 30% more voltage out at low current draws.
This is one case where more isn't always better. Replacing a 5V 100mA adapter with a 5V 2A wall wort may in fact feed more like 8-9V in to your equipment at the lower current draw you actually use. This can easily cause damage if the device isn't designed to account for possible higher input voltages.
Regulated, or switching power supplies eliminate this problem, as they are guaranteed to put out the rated voltage (+/- some tolerance) from almost 0 current draw, right up to their maximum rated value. Of course, as Ripster mentioned, they do have their own issues when it comes to introducing high frequency switching noise into equipment.
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Great insight Talis, thank you. :tea:
I bought a universal laptop adapter rated at 15V-20V/4.5A (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300309841847) before reading your post, but luckily it is marketed as a switching type adapter. If you have a second to check out the above link, does that look like it will fit the bill? At $9 shipped to Brazil, I figured that it couldn't hurt to give it a shot.
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AC-DC adapters are available in all kinds of quality levels and ranges. Your best bet is probably to speak to someone in a shop that repairs consumer electronics or ham radios, as they're used to working with AC-DC conversion and having to avoid hum. They might be able to build one for you.
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AC-DC adapters are available in all kinds of quality levels and ranges. Your best bet is probably to speak to someone in a shop that repairs consumer electronics or ham radios, as they're used to working with AC-DC conversion and having to avoid hum. They might be able to build one for you.
I'll keep this as my backup plan in case the noise is too heavy with the switching adapter.
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Your best bet is probably to speak to someone in a shop that repairs consumer electronics or ham radios
You were right my friend. A radio repair guy supplied me with an adapter that does the trick for R$20 (about $11). I'll keep the universal adapter that I ordered from China as a backup when it arrives.
Thanks to everyone for their input! Now if you'll excuse me, I have some serious rocking out to do.
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At 9V the device should draw proportionately less current (assuming it works properly at 9v to begin with) and items are generally rated to err on the side of caution. So I think you could probably chance your arm with the 9VAC 780mA... but I'd try it to get out of a fix, definitely not as a permanent solution. And the official, responsible, and not-liable answer would have to be no - just get a suitable ac adapters (http://www.gadgettown.com/Laptop-Adapters/), exactly 7.5VAC and 1A or higher.