Hello Fellow Boardronauts + Question re: replacement power supply variance

[htidwell1970]

Greetings from DTLA in SoCal - I just joined this board I hope this is an acceptable place for this post.

Like many of you, I suspect... I retain and collect just about any power supply I find. I get many of them at salvage yards and hang on to the ones from discarded items and I've even found few trips and rheostats dumpster diving.

I toss most of them into a large crate in my closet without much afterthought. I have a large jar of connectots and tips labeled "dongles" - more than half of the ones I find had the cords cut off already.

This keeps me about 80% prepared for whatever strange item I might come across tomorrow that's in need of a power supply. My question.... (and I know it's going to be difficult to answer since there's no standard device, but let's assume we are in the laptop mid-range electronic small power tool range)...

*Drumroll*. What's and ballpark of acceptable variance in voltage for devices under the 30 volt DC range? Or maybe the better question is how far off is too far... for mostr small appliances and power supplies for computers and laptops - I have been comfortable using a supply with a higher amperage because my understanding is that the device will only take what it needs. I know that's in the best case scenario and does not include scenarios we where undesirable amounts of power may go looking for a new place to be or components to let the smoke out of... Generally 2 or 3 amps higher has worked out ok so far... I've used laptop power supplies that were two or three volts higher or lower than the stated requirement for the laptop when when I had no other options. I used it in moderation and kept an eye on the temperature... but I always felt like it was somehow damaging or shortening the life of the device.

Today in the front of me I have an Altec Lansing surround speaker subwoofer only one thing that requiresthat requires 13v ac. 4a. if you can find the power supply online it runs about $80 but it's hard to find and I'm already invested pretty deep at $6 I don't want to go any further hah : ) . I have a few 12 volt AC ps around here somewhere I think they're at 3a. Assumingi I don't blow the thing up with the wrong pinout that seems like a reasonable substitute doesn't it? I'm wondering if this is one of those things that would have more of a long-term effect on the life of the device work there would be short term effects or risks I'm curious to hear what your thoughts and interesting experiences power supply hacking are...

One day I'll tell you all about my unexpected introduction to the bastard leg... but not today.

Thank you!
Hollister

 

[darren adcock]

I don't understand. Surely the "device" just needs what it needs? to function as designed, unless you seek "disfunctional" for some reason we don't know about.

In terms of laptops, surely the correct PSU is cheaper than a laptop, so why risk it?

In terms of the Lansing surround sound sub;

I suspect this would mean it would either not work or just be a lot quieter, takes power to move that sub!

I'm no expert here, just answering based on similar threads I've read here

 

[73's de Edd]

Sir Hollister Tidwell . . . . .

If you have the . . . .Altec Lansing surround speaker subwoofer . . . . . and you already have . . . .
I have a few 12 volt AC ps around here somewhere.
Which should actually, only be the AC transformer.
You could then hook one of them up and expect the only limitation to be that the unit will stop at its power level production only at the 3 amp capability.
So if that continual full max power is not needed, you are fine.
Come back with the Altec lansing model number and it can then be further
researched to be sure that the manner of interconnections will be correct.

ASIDE . . . .
I'll tell you all about my unexpected introduction to the bastard leg

. . . . .the rest of the story . . . .
Being a prolific Dempster Dumpster Diver . . . . . once in my nightly runs . . . . I see this shoe sticking out from under some other items. Upon pulling on the shoe, it seems to be attached to something else.
That something else is none other than an artificial limb prosthetic.
Now it so seems that after a final tour in Iraq, a land mine resulted in the loss of my left leg from the knee down.
Unfortunately I have always experienced some discomfort from the unit which I was fitted for.
Well . . . .I tried on that unit and it almost gives me the dexterity of my original limb, so much so, that this new discard has become my MAIN unit.
Now, I just take a 3 step run and plant one hand on the rim of the dumpster and plop right on down inside for having full access to all of the goodies .
Now . . . . . you know all about my . . . . . " bastard leg ."

. . . .from the pen of Ulysses Phipps
http://www.antiqueradios.com/forums/viewtopic.php?f=19&t=223248



73's de Edd
.....

 

[Cannonball]

If you have a transformer that exceeds the current you need, it doesn't matter how much, put a fuse of the right amperage in line and the smoke will stay inside. You can also use two transformers in parallel to meet the required current. Use a fuse.

 

[Minder]

My question.... (and I know it's going to be difficult to answer since there's no standard device, but let's assume we are in the laptop mid-range electronic small power tool range)...

Today in the front of me I have an Altec Lansing surround speaker subwoofer only one thing that requiresthat requires 13v ac. 4a. if you can find the power supply online it runs about $80 but it's hard to find and I'm already invested pretty deep at $6 I don't want to go any further hah : ) .
Hollister

For permanent installations or usage, I much prefer linear power supplies over SMPS, of which I generally only use for temporary situations.
M.

 

[htidwell1970]

If you have a transformer that exceeds the current you need, it doesn't matter how much, put a fuse of the right amperage in line and the smoke will stay inside. You can also use two transformers in parallel to meet the required current. Use a fuse.

,

Thank you for bringing that up I was wondering about that this afternoon. Which was the day after I made that post... I played around a little bit with running things in parallel and series in DC like car batteries and battery chargers to charge 24v w two 12vr chargers (they were the old style heavy Transformer type not smart Chargers I'm not sure how those would react) and also combinations of the same chargers and batteries to do some light welding but again this is all in the realm of DC I understand how that works. what I'm a little unsure about is the result I would get from using at 4 volt AC adapter and a 6 volt AC adapter inp parallel- Im guessing it would be 13v would the amperage be conventionally additive in the same manner? I'm coming up low on the amperage when I source for power supplies if there's a way I could run some in parallel and raise the amperage keeping the voltage in the same ballpark that would be awesome. 6v 2a adapters and their ilk are a lot easier to come by than a 4a.

Is there an application/item category I'm overlooking that commonly uses thst ballpark size of AC output adapter? answering machines and wireless home telephones with big base stations often came in the 7 to 9 volt AC variety for about a decade or two. Some Tyco toy model car race tracks where a sea-based the little handheld variable throttles. I find most powered speakers in home audio stuff likes to have AC as a source. Sewing machine motors though those run pretty much off the wall with stepdown sans adapters.

Thank you!
H

 

[duke37]

Connecting a 4V AC power supply in parallel with a 6V AC supply will cause failure since the 6V supply will feed into the 4V supply.

Putting the supplies in series will give 2V or 10V depending on the polarity. The maximum current permitted is that of the weakest supply.

 

[73's de Edd]

You mention the . . . . . Altec Lansing surround speaker subwoofer . . . . . . if you gave the model number we could research the circuitry for the solution.