How to draw 12W DC output from PC motherboard/PSU/USB?

Question

I recently bought a Dell AX510 Soundbar speaker that fits snugly under my monitor.

However, my monitor, Dell IN2030M is a budget model, and while it does have the plastic grooves to fit the soundbar, it is missing the port where I could plug in the power connector from the speaker.

The speakers use a standard DC power connector requiring 12W.

I have the option to use an external power adapter like this, but what I'm interested in learning is if there is a way to pass the required 12W power to the speaker from the motherboard using a cable convertor, such as a USB to DC, or a PCI to DC, or directly from the PSU etc. Is there a way?

Update: I have this information from the speaker manual:

• Power requirements: DC 12V +/-5%, 1.0 A
• Total power output: 10 Watts continuous average power

Solution 1

The 4-Pin peripheral connector of your PSU delivers 12V DC. If you buy the correct cables and adapters, you should be able to connect your soundbar to it.

All together it shouldn't cost you more than 10$

---

1. Here we see the cable tree of your PSU CoolerMaster Thunder 500W together with a peripheral (Molex) connector

   

2. A 12v 4-pin molex to 5.5mm x 2.1mm power adapter cable costs ~5$.
   Don't be confused by the red+black cable colors.
   Those two used pins are the correct ones for +12V DC

   

3. The key is to find the correct connector diameter.
   According to this description it's a 5.5mm x 2.1mm barrel connector female

   

4. At this point, we need a coupler since both ends (soundbar DC cable + Molex adapter cable) are male. A female-female gender-changer coupler again costs ~5$. (or $0.80)

   

5. Surely you will need an Extension Cable which costs ~2$. Despite this, you have to find a small hole to fiddle the cable out of your PC tower and up to your monitor.

   

Solution 2

Aside from powering it from an external power supply, there are a few options, and highly depends on your setup.

If you only want to avoid running an extra cable or something, there is C13 pass through/piggyback cables. The cable plugs into the monitor but also has a regular power outlet at the end that the regular power adapter would connect to.

Alternatively, with some creative hacking, you may be able to get the power from the monitor itself. The power supply could have a spot for the 12V 1A needed, simply not wired. You would need to guess a bit after opening the monitor to see.

USB is not ideal for this. You would need a step-up voltage regulator, and even assuming 100% efficiency, you would need 5V 2.5 Amps in. Most USB ports are much more limited.

Comments

[Prerak Diwan]

Quite honestly I think it's going to be more trouble than you want. Just go get the power adapter.

[SNag]

@KronoS: Ah.. I guess I will eventually do that... my initial thought was a USB to DC converter, but USB only supports 5V (and a max of 1.5A), so that isn't enough for powering a 10W speaker. I still do think there's a way (crooked though it may be), hence this question!

[Ƭᴇcʜιᴇ007]

You'd be better off (IMO) opening the monitor and tapping off its power. But as @KronoS suggests (especially if you don't have electronic experience), it'll be more trouble than it's worth, just buy an adapter (or upgrade your monitor to the one that's compatible). If you want to go the custom hack and solider route, then this is probably better off on a different StackExchange site.

[Daniel B]

The wattage doesn't help. Please state the required voltage and amperage.

[piernov]

USB won't do it : 5V and 500mA, though some motherboard allow 1.5A, it's less than the required 10W (1.5*5=7.5W). The computer's power supply surely can deliver more than 10W on 3 differents voltage : 3.3V, 5V and 12V. So you've to know which voltage your soundbar requires (most likely 12V, which is normally delivered by yellow cables from power supply, red is 5.5V and 3.3V can vary by OEM constructors).

[SNag]

@DanielB: The speaker needs DC 12V, 1.0A (I've updated the question).

[Daniel B]

At least it’s a common value. The only problem is the male plug, other than that pretty much any universal power supply should do.

[SNag]

@DanielB: I see. So this speaker was built specifically to be plugged into a female on the monitor, which mine lacks. I already have a universal power supply adapter with a male output, so I guess I could buy a simple female terminal and solder it on the speaker to use the adapter with it.

[nixda]

@SNag What's your exact PSU model?

[SNag]

@nixda: Does it matter? My PSU is a CoolerMaster Thunder 500W, and my motherboard is a Gigabyte GA-Z77M-D3H.

[nixda]

I'm sure I'm missing something obvious. I'm no expert at these things.

[SNag]

Hey! Thanks for the detailed explanation! According to this page though, the 12V lines from the PSU output 24A and 21A, not the required 1A. But your overall answer makes sense. And I also see now why @KronoS said it's going to be more trouble that it's worth!

[Dane]

Also, @Nixda, excellent answer. You went above and beyond in finding all the items for purchase, avoiding any wiring or soldering. Upon consideration, I'm wondering if the sound bar would be bad news for the computer, since it can really draw a lot of power and is variable based on the volume output.

[Dane]

I just posted my question over on the Electrical Engineering site: electronics.stackexchange.com/q/109661/41552

[nixda]

@Snag the 12V lines from the PSU output 24A and 21A, not the required 1A -- I guess here is a misunderstanding how current and voltage works. Please read the part about Current rating in this electronics.SE answer. In short: PSU current rating must be higher than your soundbar (24A > 1A » ok) while voltage rating must fit exactly your soundbar requirement (12V = 12V » ok). Please also read Dane's electronics.SE question. Your PSU output capacity is 500W, the additional 10W from your soundbar shouldn't be a problem

[SNag]

@nixda: This is all excellent information. I learnt many things today! Thank you both!

[SNag]

I finally managed to procure the necessary components, though not the exact ones from your answer, (I bought a Molex male and a DC female connectors and joined them with the required length of wire) and got this working! Absolutely no problem with sucking 12W out of my 500W PSU! Everything's working great now! Thanks nixda and @Dane!

[nixda]

@Snag Can I see pictures/links of those items you bought? :)

[Dane]

@SNag I'm definitely interested in seeing your final solution. It would be worthwhile to post your solution as an answer to this question, in case it is useful to others in a similar situation.

[SNag]

@Dane, nixda: I will post them soon.

[Scott Prive]

I'm not sure why this downvoted, as it does have value. While the OP did specifically ask how he could draw the power from his PC, he also indicates he was doing this because there was no 12v at the monitor. cde's approach is clever: run a power splitter behind the monitor, and use a12V adapter. While this is bulkier, if you have a 12V power supply available then it's a great solution. Also, if you're wall mounting, you can hide the extra power supply behind the screen using cable ties (and that way you're only running 1 power wire to the outlet). Folks please use the downvote sparingly...