AC Adapter -- sanity check

Jstas

OK, all you 'lectric gurus out there, I need a sanity check. Mainly because I'm finding it difficult to believe that it could really be this easy.

I have a piece of gear. Well, it's a powered speaker. It's not even mine, it's the GF's. They are computer speakers from a company I never heard of. Nice little jobbies, sound pretty good. She got them when she was living in England. They look like those itty bitty Altec Lansing line arrays with the 1 inch aluminum drivers?

Anyway, the thing has this AC adapter. It's a brick, like a laptop adapter but bigger. It's switchable because, well, obviously it's from the U.K. so the power feed is different. But since, it's an AC to DC transformer, all that matters is the output.

Well, her cats chewed through the power cable and it's gnarled pretty bad. They chewed through the end and since it's captured, I'd have to take the whole thing apart to replace the power cord. That's a problem because the guts are encased in epoxy except for the power transformer. The company that made this adapter still exists but this thing went out of production 10 years ago. They have printed boards left, that's it. They offered to mail me a board and a parts list if I wanted to assemble it. I don't, really, but if I have to, I will.

So I had a brain **** and thought "Why not a universal, switching adapter? All that matters is the output, not the input." I thought nah, who's gonna have an 18.5V adapter running at 1-2 amps? Nothing runs at 1-2 amps anymore. Not at 18v at least!

Then I found this guy: http://www.sunvalleytek.com/universal-laptop-ac-adapter-90w-variable-7-dc-voltages-output-p-1088.html

The output is apparently progressive as well as switchable. It also has a voltage setting of 18.5V at 5A max. If that's the case, this speaker thingy runs at around 1-2 amps. Now, my brain is telling me that if this puts out 5A max at 18.5V, this should power these speakers without blowing up the little amp. The number that matters for that is 18.5V and that's one of the options.

However, my inner skeptic is telling me I'm an idiot, no way it's that easy and that I'm gonna blow up my GF's stuff. Normally, I wouldn't care, I'd try it anyway and what comes is what comes. Since this isn't mine, she is attached to them because it was a Christmas gift from her grandma and replacement is difficult, I don't want to ruin it on her.

So could somebody please give me a second opinion on whether this will work or not so I can stop worrying about and just fix the damn speakers. Hopefully I can get it done before Christmas.

Summary of issue:

- Speakers from U.K. need 18.5VDC at ~1.5A input
- Power supply in link puts out 18.5VDC at 5A maximum
- Will the maximum amperage of 5A be an issue for the speakers only requiring ~1.5A

ben62670

Higher amperage will not hurt it. It may actually be better. The amp only draws as much current as it needs.

Joe08867

should work fine. Like Ben said the amp will only take what it can use.

zingo

ben62670 wrote: »

Higher amperage will not hurt it. It may actually be better.

Upgrading the power supply... :biggrin:

Polkersince85

I think the HP/Compac notebook adapters 18.5v at 3.5A.

bikerboy

Put a new cord on it that is cat proof and call it good.

mmadden28

Yep your good. A higher amperage/current capable AC adapter is just its max rating. a 1A in place of a .4A is fine, however you wouldn't want to use a .4A adapter in place of a 1A adapter.

Generally another thing to keep in mind is whether the output of the AC adapter is AC or DC. Most AC adapters are DC output, but some are actually AC output. And if DC, you need to ensure the correct polarity.

In some cases, when in a pinch and when using 'disposable' electronics, I've substituted a higher voltage AC adapter (but appropriate polarity/current rating) with no ill effects. Such as a 12V adapter on a 5V or 9V device. This won't always work and it's not recommended, but possible. Of course I've fried a few things too. My thinking is that the 'successful' devices had thier own voltage regulator so the extra voltage wasn't much of a problem.

[Deleted User]

ben62670 wrote: »

Higher amperage will not hurt it. It may actually be better. The amp only draws as much current as it needs.

Agreed. The thing to watch is the wiring on the adaptors output. I've had adaptors where it was reversed and didn't notice until it was too late. It would be wise to check the polarity of yours is before you plug it in. :cool:

Jstas

Got the adapter today. Works like a champ, no problems...yet! If it blows anything up, I'll let ya know. Playing right now without a problem though.

ESavinon

Dont forget to replace the cats.:biggrin:

ESavinon

Actually, The higher current should keep the cats away if they decide to chew thru the new power cable. 5A should be enough of a deterrent.

Jstas

Well, yes, provided it stays plugged in. She goes around the house unplugging everything because she swears it saves her money on the electric bill. I ran an experiment and I think unplugging everything saved her a whole $1.13. I asked her if the approximately 4 hours she spends a month unplugging everything and plugging it back in was worth $1.13. A whole 28 cents an hour.

She told me to shut up.

If she moves in with me, she's gonna have a hard time with all the computers in the basement that run 24/7.