Using 15V laptop power supply on t-amp

[aussiebuddha]

Hi Guys I've got a T-amp I've been using for a while with a 12v 4amp power supply.
I just found a spare laptop 15V 5amp power supply around.

Would it be safe to use it or will i blow up the t-amp?
I understand the more power supply the better sounding the t-amp will be, but i dont want to risk frying my baby.

I measured the power supply output with my fluke and it's 15.23v

Regards

[Buckapound]

This is probably not the power supply for you.

I drove my T-Amp into thermal shutdown with a 14.1 v LCD monitor SMPS. Chip temp measured around 115F at the time--even with a heat sink. When it cooled down and I went back to a different power supply, the chip was fine. So, the internal protections work.

In the case of my particular SMPS, some more knowledgible folks than I pointed out the resistor on the bottom of the circuit board that set the voltage. I paralleled it with a 20K pot and dialed down the voltage to 13.1v and now it works just fine with the T-Amp.

Some PSUs have a voltage adjusting pot on them, so it might be worth cracking the case on yours to see.

--Buckapound

[aussiebuddha]

Not a bad idea to open the supply.
Only problem is I've got no idea how to, have u ever opened one of those bloody things?

Cheers mate

[djQUAN]

in most adapters, the case is glued together. if yours is different, you might find screws hidden under rubber feet or stickers.

[aussiebuddha]

nope, no screws under stickers or rubber feet.
That means I actually need to literally crack it open, right?

[Buckapound]

Well, if it's one of those two-piece plastic cases--and I'm assuming it has no visible screws or you wouldn't be asking--you just stick a thin screwdriver in the little gap between the two halves and twist to open it up like an oyster. They're usually glued together in little spots along the edges, at least the ones I've pried open.

I should mention that sometimes on small electronic devised there are screws that may be hidden either by the product label, or sometimes by stick-on rubber feet, as is the case with the SI. So check that if you haven't already.

Once you're done monkeying around, you can either glue it back together with super glue or find a better-looking project box to put it into.

--Buckapound

[Gorilla]

Just speculation, but I would think that such a supply would be designed for dirty digitial electronics over a relativley small bandwidth. It may be worthwhile experiementing with some extra filtering and decoupling capacitance.

[Buckapound]

Some of those little plastic-cased SMPS are of decent quality and have actually been working well with the Class D amps.

According to what others have said, there may be issues with changing the capacitance at the output end of the SMPS supplies.

Cheap as they are in surplus, it's probably better to find a workable one rather than invest a lot of time and energy improving one that's not so great.

--Buckapound

[aussiebuddha]

yeah i think you're right mate.
I took a couple of hours to try and pry this one open and is practically impossible.
The bloody plastic is just too thick.

I might try and pickup a used one somewhere else...
or forget about the whole thing completely as I'm already running a relatively decent (i think) 12v 4 amp power supply.

[Buckapound]

If it comes down to a matter of principle (that's how I would view it, as a personal challenge), your case-opening efforts might be aided by the use of a razor saw. In the US, at least, these can be found in any hobby or art supply store. They have a super thin blade about 12 cm long and backed by a folded over piece of metal like a small back saw.

Because these saws cut such a thin kerf, they breeze through plastic. Even if you are worried about getting all the way through and damaging the innards, a partial cut can weaken the plastic to the point where it will split when you try again to crack the seam.

--Buckapound