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running creative gigaworks t20 speakers in my van

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Rainbow_Zanadar

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I'd like to use a pair of Creative Gigaworks T20 speakers as the main source of sound in my van.

The van doesn't have a stereo and I'd like to use an MP3 player as it, and my Nokia 5800 both use 3.5 mm stereo jack plugs.

My problem is that they are powered by a 12 AC PSU running at 2.9A

I'd rather make something that plugs between the cigarette lighter and the speakers, than open and fiddle with the speakers.

Any Ideas would be very much appreciated.
 
The speakers are rated to have a total output of 28W RMS. If they are class-AB then their draw from 12VDC is about 48W (including wasted heat) but the 12V power supply is only (12V x 2.9A=) 34.8W so the numbers do not add correctly. Maybe the amplifiers in the speakers are switching class-D types.
I don't know if the amplifiers will blow up when fed the 14.4V from a car that is charging its battery.
 
Its not that easy to make AC from DC. You could use an off the shelf 110 volt inverter and plug the wall wort into that. It would work but wast alot of power. You should be able to find PC speackers that will run off 12VDC. Andy
 
You should be able to find PC speakers that will run off 12VDC. Andy
The speakers do run off 12VDC. But we don't know if they will survive if fed 14.4V from a car that is charging its battery.
 
The OP said
My problem is that they are powered by a 12 AC PSU running at 2.9A

If thay are realy 12voltDC input, then do not leave them pluged in when starting the van. Thay should be able to handle a few extra volts with out harm but the OP is worred he can regulate the van power to 12 volts with a zener diode and a power resistor. Andy
 
he can regulate the van power to 12 volts with a zener diode and a power resistor. Andy
Yes, if the load current is low. But here the load current is 2.9A so a zener diode would need to have a current at least as high which would produce a lot of wasteful heat. When the music level is low then a zener diode would heat with at least 12V x 2.8A= 33.6W. The resistor would heat with at least (14.4V - 12V) x 2.8A= 6.7W.
 
This is a UK set of speakers and the input of the PSU at the wall is 240 volts, the output is 12 volts AC.

I have since opened the main speaker and can see a bridge rectifier on the back board but Creative have put a lot of clear epoxy all rount the power board inside the main speaker and it looks like it will take a lot of work to clear it off.

I'm currently running a set of cheap 2.1 active PC speakers in the van as I removed the power cord and bridge rectifier from them and connected a spare live feed from the fuse box to where the bridge rectifier turned AC to DC.

Trouble is the CHEAP speakers give poor quality sound, whereas the Creative T20's will be awesome.

I may have to get the back board out and pull the bridge rectifier out after all.

Thanks for your input guys, I really appreciate yout thoughts.
 
If the power supply is simply a 12VAC transformer then the bridge rectifier inside will make about 15VDC. It will work fine from the 12V to 14.4V from a car.
The little "woofers" are only 2.25" in diameter but produce mid-bass sounds well.
 
Yas audioguru, I agree with your comments on the little "woofers".
The T20's have an amazingly clear output at any volume and produce very little distortion.
Clearly the best speakers I have ever had on my PC and should sound great in the van.
 
My pc has speakers that are 3" in diameter with huge magnets. Each is driven from a low distortion 3.5W amplifier. They produce frequencies down to about 80Hz. The drivers look like this:
 

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A bass speaker is supposed to move a lot of air. Your tiny little 2.25" bass speakers cannot move much air.
Maybe you don't know what good deep bass feels like.
 
I meant how big the magnets were not the speakers themselves.

And I think I know what bass sounds like considering I play both a 5 string fretless Cort Bass and an Ashbory through am 18" bass bin.
 
If this is true
If the power supply is simply a 12VAC transformer then the bridge rectifier inside will make about 15VDC.
than you dont even need to modify the speakers at all. You can hook up 13 volts DC from the van to the AC input and it will work, The power will go thrue the bridge rectifier with either polarity. You will get a small voltage drop across the bridge, but it will work without moding the speakers. Andy
 
This T20 is actually I'm looking to buy soon as this one is one of the great desktop pc speakers available..
A bass speaker is supposed to move a lot of air. Your tiny little 2.25" bass speakers cannot move much air.
Maybe you don't know what good deep bass feels like.
This is obviously not like your little speakers. T20 is designed to deliver "big sound" from a tiny unit. They claimed to have used specially made drivers and if my memory is correct:)D), independent active crossovers+amplifier inside! It costs too much.

But I haven't experienced the performance directly....just only a assumption :)
 
This is obviously not like your little speakers. T20 is designed to deliver "big sound" from a tiny unit. They claimed to have used specially made drivers
They can claim anything they want. The 2.25 inch "woofers" are too small to produce deep bass sounds.

Some of the reviews say that the little speakers are fine for small desktop pc speakers. They say there is no low bass and they are not very loud.
 
If this is truethan you dont even need to modify the speakers at all. You can hook up 13 volts DC from the van to the AC input and it will work, The power will go thrue the bridge rectifier with either polarity. You will get a small voltage drop across the bridge, but it will work without moding the speakers. Andy

Thanks 4pyros, I'll give them a try tomorrow and let you know.
 
Ok, So this morning I went to maplin to purchase a cigarette lighter power supply to drive the T20's, The young man in the store said he had nothing that would suit my application and advised me to go to Halfords across the road as they deal with car stuff.
In Halfords I purchased a multi-voltage, multi-device charger.
This thing plugs into a cigarette lighter socket and can be set to 3, 4.5, 6, 9 or 12 volts and can be set to positive or negative center pole.
The T20 were positioned in the 2 front storage compartments using double sided reg. plate tape.
The charger was plugged into the 12 volt ac on the back of the right speaker, the left speaker plugs into the back of the right speaker and the 3.5mm audio in was plugged into the right speaker and then into the audio out on my Creative Zen Touch 20Mb.
Power on the charger, power in the T20's, power on the Zen, and listen to the sweet sound of all my Mp3's at full tilt all day long.
The 12volt dc from the charger goes into the 12volt ac of the T20's, through the bridge rectifier and powers up the T20's without fault.
On this occasion, 12 volt dc to 12 volt ac needs no extra equipment.
 
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