a/c adapter
#1
08-23-06, 10:02 AM
a/c adapter
I have to replace an adapter for a guitar effects pedal. The one that came with its was 9V 500ma. None of the local electronics stores in my area carry it. One place I went to tried to sell me on a 11v 800ma adapter. The guy told me it would work fine, that the device would only pull the power it needs. I didn't buy it because I'm not sure he knew what he was talking about. Is he right about this?? thanks
#2
08-23-06, 10:15 AM
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Location: Cinti, OH
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I couldn't find any in our store but Radio Shack has one.
You may have to copy and paste the link.
http://www.radioshack.com/product/index.jsp?parentPage=search&summary=summary&techSpecs=techSpecs¤tTab=summary&cp=&custRatings=custRatings&features=features&accessories=accessories&productId=2049687&origkw=9+volt+power&support=support&kw=9+volt+power&tab=techSpecs
You may have to copy and paste the link.
http://www.radioshack.com/product/index.jsp?parentPage=search&summary=summary&techSpecs=techSpecs¤tTab=summary&cp=&custRatings=custRatings&features=features&accessories=accessories&productId=2049687&origkw=9+volt+power&support=support&kw=9+volt+power&tab=techSpecs
#3
08-23-06, 10:22 AM
9V vs 11V= 22% over voltage. Don't think I'd trust it. Check "the shack" for a 9 - 13 volt 800 ma adapter. You can set it for 9 V. Costs about $18.
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Last edited by DIYaddict; 08-25-06 at 09:29 AM. Reason: Deleted only empty space with no words
#5
08-25-06, 08:39 AM
I finally found a place the has something close to what i need. Like I mentioned the one I'm replacing is 9v 500ma. The one I found is 9v 850ma. I read in the one post that the ma has to be the same or higher. Will this one be ok to use?? thanks
#7
08-25-06, 08:51 AM
Originally Posted by andy5150
I finally found a place the has something close to what i need. Like I mentioned the one I'm replacing is 9v 500ma. The one I found is 9v 850ma. I read in the one post that the ma has to be the same or higher. Will this one be ok to use?? thanks
#8
08-25-06, 09:11 AM
I see what your talking about with polarity. The back of the unit under the ac input has a diagram on it. Negative symbol with a backwards c and then +. I assume this is the polarity you are talking about and the adapter has to have the same exact diagram on it. I checked out other adapters around my house and they are all different polarity. I never noticed that. Also my old and the adapter I might buy both have input ac and output dc on them. thanks
#9
08-25-06, 09:49 AM
The C is really a representation of the outer shell of the connector. the part in the middle is the polarity of the center pin.
With DC this is very important. if you you get it wrong either it will just not work, or you will let the smoke out of the device.
If you let the smoke out, you are done. The smoke can only be put in at the factory.
With DC this is very important. if you you get it wrong either it will just not work, or you will let the smoke out of the device.
If you let the smoke out, you are done. The smoke can only be put in at the factory.
#10
08-25-06, 10:44 AM
great advice. I never knew about the polarity thing. I must have been very lucky in the past. I always went by volts and amps when switching adapters. Never even gave thought to the strange diagrams. Something else I noticed too is the diagram is stamped two different ways for the same center. Sometimes the negative symbol is on the left for a negative center with a backwards c and other times it is on the right with normal c and is also negative center. I guess this is just the preference of the company. thanks
#11
08-25-06, 12:23 PM
Member
Originally Posted by andy5150
Sometimes the negative symbol is on the left for a negative center with a backwards c and other times it is on the right with normal c and is also negative center. I guess this is just the preference of the company. thanks
Most cars in the US are 12VDC negative ground. The positives are fused and fed by a red cable from the battery + terminal. In a DC system, electrons flow out of the negative battery post and back thru the positive battery post. So positive ground would probably make more sense.
On the other hand, in a telephone central office (aka wire center) the battery system operates at -48VDC, which means the positive bus is at ground potential and the negative is HOT.
To further complicate things, in some offices the red wires are negative and the black wires are positive. However a lot of offices just have grey wires with tags telling you what they are carrying.
#12
08-26-06, 12:31 AM
Originally Posted by joed
The amperage(ma) must be the same or higher.
This statement is True if the power pack has a built in voltage regulator.
80 percent of the power packs don't have regulators, some-some items can be damaged by getting a higher current rating on a replacement power pack.
Power packs without voltage regulators, the current rating is more of a required load to bring down the voltage to a required specification.
If you don't know keep with the same rating of the original power pack, and that can be iffy.
http://forum.doityourself.com/showthread.php?t=219847
http://forum.doityourself.com/showthread.php?t=248540
