question about AC vs. DC power source
Mar 16, 2006 at 8:52 AM Thread Starter Post #1 of 8

davidhw

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I'm giving serious thought to purchasing the Micro DAC and Micro Amp from Headroom. I've noticed that these units both have the battery option for portability; however, I would not be using these anywhere else but on my desktop with my computer-as-source, so I'd be using the AC option exclusively. Yes, I could move up to the Desktop model with DAC, but that would be $850, vs $600 for the Micro DAC and Micro Amp.

My question: is there any difference in quality (effect on sound, clarity, and so forth) between using batteries and using a standard AC wall outlet? I'd hate to purchase something optimized for battery use when I'll never use the battery option.

TIA.
 
Mar 16, 2006 at 8:59 AM Post #2 of 8

TheSloth

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All headphone amplifiers are DC internally. The AC wall wart converts the AC to regulated DC power. That's a long way of saying it's the same DC whatever power source you are using. In the Micro Amp, the difference between the wall wart and the batteries is quality, and voltage. A battery is a near perfect DC source, with no noise and perfectly clean power delivery. The 9V batteries provide + and - 9 volts to the electronics in the Micro, whereas the wall wart provides + and - 15 volts. The increased voltage allows for a greater maximum output (unlikely to be required unless you are trying to use your headphones as speakers
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), and a little bit more headroom for dynamics. However the less clean power source from the wall wart means that the overall sound is a little grainier and less definied.

The differences are however very, very small and you will find the amp exhibits basically the same sonic signature either way. And if you prefer the battery sound, you will get 20 hours out of Lithium 9V batteries.

As an overall consideration, all DC electronics are optimised for clean power delivery in that they will always sound at their best that way. Therefore all amplifiers are inherently 'optimised' for either batteries or a very high quality power supply.

Enjoy!
 
Mar 16, 2006 at 9:05 AM Post #3 of 8

davidhw

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Did not know that fine-line definition of DC. I just thought DC=battery, AC=outlet. That's what I get for majoring in liberal arts. LOL.

You learn something new every day. Thanks. :)
 
Mar 16, 2006 at 6:19 PM Post #4 of 8

vo328

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Quote:

Originally Posted by TheSloth
And if you prefer the battery sound, you will get 20 hours out of Lithium 9V batteries.


One quick note of caution. Battery life will depend on which electronics module you opt for on the Micro amp. The Desktop module will likely be the best choice for you, given that you plan to use the AC adaptor most of the time. On battery power, you're likely to not get more than 6-8 hours with the desktop module in place, versus 20 hours or so with the micro module. Either way, get ready for a wonderful component! Your ears will thank you... but your wallet won't.
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Mar 16, 2006 at 8:14 PM Post #5 of 8

TheSloth

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Quote:

Originally Posted by vo328
One quick note of caution. Battery life will depend on which electronics module you opt for on the Micro amp. The Desktop module will likely be the best choice for you, given that you plan to use the AC adaptor most of the time. On battery power, you're likely to not get more than 6-8 hours with the desktop module in place, versus 20 hours or so with the micro module. Either way, get ready for a wonderful component! Your ears will thank you... but your wallet won't.
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http://www6.head-fi.org/forums/showt...=136059&page=2

Have some faith my friend... The 20 hour reference was, as I said, to Lithium 9V batteries, not Alkalines, running the Desktop Module. Lithium 9V batteries have a mAh rating of about 1200, versus around 550 for Alkalines, giving about 20 hours on the Desktop Module and nearer 40 with the Micro.

With the Micro DAC, you will get about 16 hours from Lithiums. You can then switch the batteries around (as one of them is used far more than the other in the DAC) and get another 10 hours from the same batteries.

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Mar 16, 2006 at 8:42 PM Post #6 of 8

vo328

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Faith 'o plenty here!
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I missed the Lithium reference in my first reading...

I thought the Lithiums don't fit well into the Micro amp? Even the Maha's that I use don't fit as well as an alkaline would. From a NiMH perspective, I see between 6-8 hours in my Micro amp with desktop module.
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Mar 16, 2006 at 8:48 PM Post #7 of 8

TheSloth

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Quote:

Originally Posted by vo328
Faith 'o plenty here!
smily_headphones1.gif
I missed the Lithium reference in my first reading...

I thought the Lithiums don't fit well into the Micro amp? Even the Maha's that I use don't fit as well as an alkaline would. From a NiMH perspective, I see between 6-8 hours in my Micro amp with desktop module.
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Not Lithium Polymer, Lithium. Not rechargeable... the same size as alkalines, and a little lighter too.

I fail to see how NiMH rechargeables could get 8 hours with a Desktop Module:

mAh ratings, average:

NiMH Rechargeable - 200mAh
LiPO Rechargeable - 400mAh
Alkaline - 550mAh
Lithium - 1200mAh

Regarding the NiMH fit, are you sure you are folding in the little rubber flap when you use them?
 
Mar 16, 2006 at 10:04 PM Post #8 of 8

vo328

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Hmm, not sure what to say. I'm able to consistently get that much life out of my NiMH's. In fact, just today, I've been using my Micro amp between my DT770 and KSC35, and it has now been 5.5 hours. Stilll going strong.

Thanks for the tip on the rubber flaps. I wasn't folding them into the top of the enclosure, and after doing so now, the back end fits on much better.
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