Power for O2+Dac?

[elliott35]

So this is just an idea I had.... Does anyone know if it would it be possible to get a connector for my corsair axi860 psu that would power the O2 amp through its normal power plug? The included power supply (from mayflower) is a class 2 PS with an output of 12VAC @ 200mA. 

What I want to do is build the O2 into the front of the computer without any external wiring (just powered by my psu, and connected to an internal USB header).

The benefits for me are twofold: cleaner power for the amp, ( I get pops and crackles from power jitters in my building) and a cleaner desk.

My O2 has rear power, so it would be really easy to build it into my case.

If anyone has any tips or thoughts it would be appreciated.

 

Thanks,

Elliott35

 

[creatip123]

It should work. Just get an unused powered connector from PSU. Find which cable color is the power line (+ and ground), snip them, and extend it to a power plug that matches the power jack on O2.

 

Be careful though, as that's electricity connected to the PSU. A short or something goes wrong, there's a potential the PSU will fry, taking some other peripherals with it....

[NannerBeans]

Ehhh having it in your case kinda defeats the purpose of an external solution getting the audio stuff away from noisy computer components. I personally would just feed the cable through one of those external watercooling grommets if I had to though. 

[elliott35]

I would be putting it in a drive bay so It would be separated from other components. Also, I would leave its casing intact for further shielding. I have a Bitfenix prodigy, so there aren't really any external liquid cooling holes. And I kinda want to avoid drilling into the top or bottom.

 

I'm still a little stuck on the power bit... I am definitely not an electrical engineer (just generally handy with computers). Would I be able to get a plug (molex?) for my psu that converts to a positive and negative for the O2?

[ShearMe]

The 24-pin on an ATX PSU has +12V yellow wires and a -12V blue wire, but your molex/sata power connections aren't going to have that blue wire. I don't know the best way of going about getting the -12V from the PSU.

 

Also, straight from the designer's blog:

 

• AC Wall Transformer – There has been some confusion over the wall transformer and it’s a critical component. Most wall transformers put out DC but the O2’s power supply requires at least 13.5 volts AC. The ideal transformer would be rated at 14 - 16 VAC and 400 mA or higher. In North America the Triad WAU12-200 from Mouser is rated at 12 volts but is really about 13.5 VAC with no load, and on normal 120 volt line voltage works fine for anything but full power sine wave testing or driving rare low impedance power hungry cans. If your line voltage is below 117 VAC  or 235 VAC, and/or you plan to drive difficult low impedance headpones (i.e. HiFiMan planars), I would suggest a 14+ VAC transformer at 400+ mA.The best Mouser transformers are the WAU16-400, 412-218054 or WAU16-1000 CUI. But those are more expensive than the WAU12-200. The WAU20-200 also works for higher impedance headphones. At least some European 230 volt input 12 VAC output transformers only measure around 11.5 to 12 volts on normal line voltage and won’t work (especially if designed for halogen lights). You can also change the power jack to a 5.5mm x 2.5mm version if needed to match the plug of different wall transformers.

So it seems, even if you were to get the -12V, you'd still have to find a way to up the voltage.

@t0wer, any insight?

[elliott35]

Huh... Well the 24 pin is certainly occupied. 

 

I do find it interesting that Mayflower packages a 12VAC @200mA power supply when NwAvGuy (I assume that's where the quote is from) is recommending more volts and amps. Especially pertinent to me as I have freekin Hifiman planars.....

 

Maybe a pci lane could power it? I'm looking at a pin out of a pci lane and it seems to have both +12 and -12 not sure if its AC tho.

 

Assuming that it is impossible to power the O2 using an atx psu... Would anyone have a recommendation for a high quality power supply for the O2 (one within NwAvGuy's specs)? or are the Triad ones still the best?

[ShearMe]

Huh... Well the 24 pin is certainly occupied. 

 

I do find it interesting that Mayflower packages a 12VAC @200mA power supply when NwAvGuy (I assume that's where the quote is from) is recommending more volts and amps. Especially pertinent to me as I have freekin Hifiman planars.....

 

Maybe a pci lane could power it? I'm looking at a pin out of a pci lane and it seems to have both +12 and -12 not sure if its AC tho.

 

Assuming that it is impossible to power the O2 using an atx psu... Would anyone have a recommendation for a high quality power supply for the O2 (one within NwAvGuy's specs)?

 

The PSU Mayflower uses is the Triad mentioned in the quote I posted. Though spec'd at 12V it actually does 13.5V.

 

If your house wiring is junk you might want to simply get a UPS to plug your stuff into.

[MayflowerElectronics]

The power supply we include actually outputs more than 12 VAC, and it was on his recommended list of power supplies. The next power supply would've added another $10 onto the cost of the amp and we chose not to use them.

 

The WAU16-400 would be all that you need. I also don't recommend sticking this amp into a computer. The point of having the amp outside of the computer is not to pick up any electrical interference which is in an abundance in a computer system.

[elliott35]

Yea, seems like allot of work anyway. Thanks for the replies.

 

 

Last question, I promise...

 

Seeing as I have Hifiman HE-500's, should I upgrade the power supply to a WAU16-400? I have been reading about headphones overdriving the O2, would the WAU16-400 help that issue? JDS recommends keeping windows volume at 80% but I get distortion whenever its above 75%. I am a complete nub -- I know...

[creatip123]

 I have been reading about headphones overdriving the O2, 

 

 

This is the first time I've heard a headphone (or sound device) overdriving an amp, ever....

[NannerBeans]

My o2/odac came with a wau12-1000. Doesn't seem to be much of a difference from the wau12-200 I have as well. 

[elliott35]

My o2/odac came with a wau12-1000. Doesn't seem to be much of a difference from the wau12-200 I have as well. 

 

What is the impedance of your headphones?

[t0wer]

a pc runs off DC, the o2 from the wall takes AC(24v, peak to peak),

 

but now that I think about it, you might be able to go through the battery terminals.

It would still have the power regulation and the front power switch would still work.

 

you would want to keep the aluminum case on to prevent any interference/noise getting to the preamp stage.

 

 

I haven't tried putting 24v over the battery input, so if the magic smoke comes out, it's not my fault.