I recently got a 5.1 soundcard for my pc, and decided to repurpose some old bookshelf speakers as my rear speakers. I decided to use a TA2020 based amp as my amplifier because 230V amps usually don't come in that price range.
For power, I could've gone the way of getting a dedicated 230v-12v supply, but I already had an adjustable battery charger laying around (it has a slider to select 2v, 6v or 12v output), with an output of 600mAh which should be enough for a TA2020. I decided not to cut off the alligator clips on the ends because I might still need it in the future.
Well, right now when I hook up my speakers, screw the power wires into the sockets and then clip the other ends of the wires with the alligator clips, nothing happens. Bummer!
My question is, can a battery charger even work as constant power supply? Would it work if I snipped off the alligator clips and screwed the unisolated cables right into the amp? What if I bought 12v Switching Power Supply? Could I strip the isolation off a standard 3-pin power cable, plug the wires into that and then things would work?
Or what about this 12v power supply for a printer. If I stripped that, it should potentially work, correct?
Thanks for your help guys
For power, I could've gone the way of getting a dedicated 230v-12v supply, but I already had an adjustable battery charger laying around (it has a slider to select 2v, 6v or 12v output), with an output of 600mAh which should be enough for a TA2020. I decided not to cut off the alligator clips on the ends because I might still need it in the future.
Well, right now when I hook up my speakers, screw the power wires into the sockets and then clip the other ends of the wires with the alligator clips, nothing happens. Bummer!
My question is, can a battery charger even work as constant power supply? Would it work if I snipped off the alligator clips and screwed the unisolated cables right into the amp? What if I bought 12v Switching Power Supply? Could I strip the isolation off a standard 3-pin power cable, plug the wires into that and then things would work?
Or what about this 12v power supply for a printer. If I stripped that, it should potentially work, correct?
Thanks for your help guys
Depends on the battery charger...
It might detect that the amp has no voltage of its own (like a battery) and see the amp as a faulty (0 volts) battery and refuse to power up.
Battery chargers also have the ability to go way over 12 volts to charge batteries. Voltages up to 16 to 18 volts could be seen under some conditions. The output may also be non smoothed (just half wave rectified pulses).
Simple answer... don't use a battery charger
Edit... a laptop PSU would work. I'm not sure about the one in your link. Can it deliver the current needed ?
It might detect that the amp has no voltage of its own (like a battery) and see the amp as a faulty (0 volts) battery and refuse to power up.
Battery chargers also have the ability to go way over 12 volts to charge batteries. Voltages up to 16 to 18 volts could be seen under some conditions. The output may also be non smoothed (just half wave rectified pulses).
Simple answer... don't use a battery charger
Edit... a laptop PSU would work. I'm not sure about the one in your link. Can it deliver the current needed ?
600mA not enough , you need around 2A per channel or 4A total.
That besides all other possible problems Mooly points out.
So : no
Looks good.
Should work.
Only thing that's slightly nagging me is that it might be noisy, because they suggest only non audio applications where it would not matter (fans, Led strips, lamps, cameras, etc.) but really it should work, it costs the same to do it right than to do it wrong, let's trust the designers.
And the price is right, try it.
Looks too small.
Wouldn't trust it for more than 1A, tops.
So far the best option is the real 12V SMPS
Alright, so I think I'm getting this.
I just now remembered that I have an old laptop charger right here. It's rated for 19.5V output, with 4.6A current. Now, with my basic knowledge of Ohms law I've calculated that to downgrade this to a 12v supply I'd need to solder in a 1.5Ohm resistor, rated at about 32W. But wherever I go to look, there's tons of different resistor types, and ratings are usually super low, like 1/2W. What kinda resistor would I need to get if I wanted to repurpose my old charger?
I just now remembered that I have an old laptop charger right here. It's rated for 19.5V output, with 4.6A current. Now, with my basic knowledge of Ohms law I've calculated that to downgrade this to a 12v supply I'd need to solder in a 1.5Ohm resistor, rated at about 32W. But wherever I go to look, there's tons of different resistor types, and ratings are usually super low, like 1/2W. What kinda resistor would I need to get if I wanted to repurpose my old charger?
Edit: I should be able to just wire two resistors in a series on the cable, correct? So 1 Ohm, 10W + 1 ohm, 20W should = 2 ohms, 30W, right?
A resistor only works if your current draw is constant. With an amp, it isn't - it depends on load and amplitude. And burning 32W in a resistor to feed a class D amp doesn't sound very wise either.
Regulated 12 V supplies are cheap and plentiful.
It doesn't work that way .
Voltage drop will be dependent on load current which is varying all the time, so during silence you will still have full voltage, which will blow your amp, and at high power will kill the supply voltage.
You need a real regulator after that supply , something like the Tiny Giant:
http://musicpcb.com/wp-content/uploads/2011/02/Tiny-Giant-Build-PDF-rev2.pdf
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