Use computer SMPS power to desktop speakers

[cha_indian]

Hello,

My computer speakers are 10 year old Cambridge SoundWorks 2.1 ! recently the Power Brick failed and I tried to power it up by creating a PSU using the local transformer but the SQ is gone bad. Was wondering if there is way to use the desktop SMPS power to supply to the speakers ?? SMPS is Cooler Master 460W ATX unit.

thanks,
Chandan

 

[anuragn]

Even I had tried using SMPS. But did not work out.
Finally bought a good quality transformer (local). Pl ensure that the trafo is rated for atleast 50% more than what is printed on the orginal brick. This is because most of the local trafos do not supply full rated power.

 

[cha_indian]

Are you the same Anuragn here : Using PC SMPS Unit As a Power Source for Creative Speakers - Page 2 - Team-BHP

What happened in your case ?

 

[baijuxavior]

For amplifiers, a transformer based power supply is always best. A few years back my creative 2.1 PSU died and I got the transformer rewound but the SQ was deteriorated because the new one was under powered.

 

[anuragn]

Are you the same Anuragn here : Using PC SMPS Unit As a Power Source for Creative Speakers - Page 2 - Team-BHP

What happened in your case ?

Ha ha ha. You caught me right!
I did the same that I advised you to do: Got a good locally made trafo. Original one was rated 12V/2.9amp. I got one with 3amp rating from a shop in Lamington road. They used to make transformers on order and had a few standard rating ones ready off the shelf. Unfortunately, that shop is now closed down.

 

[cha_indian]

Ha ha ha. You caught me right!
I did the same that I advised you to do: Got a good locally made trafo. Original one was rated 12V/2.9amp. I got one with 3amp rating from a shop in Lamington road. They used to make transformers on order and had a few standard rating ones ready off the shelf. Unfortunately, that shop is now closed down.

In in your posts (#23) in the other forum you mentioned that you used a SMPS for powering the speakers.. what happened to that ?

 

[sasmit]

typical smps power output is too noisy to be used as is . One thing you need to check is whether your power brick output was DC or AC.
In the newer creative speakers ( cambridge ) the power brick supplies AC and it is recitfied filtered inside the subwoofer unit.

If your power brick is of the AC output type , there is no way you can run it out of the smps power.

If you really wanted to use the smps power, you would have to do some mods to the pcb inside and by pass the bridge rectifier.

 

[anuragn]

In in your posts (#23) in the other forum you mentioned that you used a SMPS for powering the speakers.. what happened to that ?

Initially it appeared to work with SMPS. But the sound output was fluctuating. I checked the smps output voltage using mulitmeter and found it to be fluctuating as well. So I learnt that SMPS is probably not designed to handle a power amplifier type of load and gave up on the idea. Although it could be because of a defective smps unit, but never bothered to try again.

 

[cha_indian]

Oh OK.. i will try and see what happens in my case. I have a spare PSU lying around .

 

[theironhorse]

Oh OK.. i will try and see what happens in my case. I have a spare PSU lying around .

a normal PSU that are rated for 400 watts and come along with the basic cpu cabinet will never give you continous power at the marketed output.
infact they hardly ever reach 400 watts to be true. to use a smps without fluctuations you would need to plonk another 4k-5k to get a antec/cooler master. that will certainly work however not worth the price investment for this project. for 5k you can get a new set of 2.1's

 

[cha_indian]

But how much power does a 2.1 amp need anyway? If we consider 50% efficiency, then it would be atleast 200W. My 95W amp consumes 300W at full throttle .

 

[anuragn]

My creative 2.1's are rated as 2x9 watts + 18W sub. That is total 36 watts. So a psu outputting even 100W should be OK. Hence I concluded that it was not that the smps was underpowered, but it was just not designed for driving amps.