Review: Portable amp roundup! 56 portable amps reviewed and compared - FINAL update 12-20-10... - Page 51  

Has anyone managed to find the iPower 500mAh Li-On rechargeable battery for less than $14.97 US ?

I'm no expert, but my understanding is that a DAC with USB will let you bypass your laptop's internal soundcard, as well as all the noisy inerts of your computer and give you a cleaner signal. So unless you have a great internal soundcard, a USB DAC is going to give you better sound from your computer than if you just amped straight out of the computer. Hope that makes sense.

If you buy a normal amp, you just connect the line out of the pc to the line in of the normal amp. line out signals are created by the PC soundcard (or onboard soundchip) and they don't produce the greatest quality sound for music. They are fine for games crash boom bang. The noise from fans, etc. also degrade the sound quality going into the amp.

If you take the digital output of the computer and let an external DAC convert it, the sound quality is better (noise is blocked since digital output is just 0 & 1s). The DAC component quality is generally better than that of the soundcards too.

So get a DAC amp and you get extra flexibility. You can listen to better quality music on your PC, yet it is still portable so it works with your DAP when needed.

That is a benefit too; you don't need to carry a wall wart PS with you when you travel (and don't go through batteries so quickly).

I should add you can get separate portable DACs and amps too. If you go that route then the DAC could be powered by the USB but the amp wouldn't be. Some portable DACs support spdif/TOSlink directly if you had a high quality source that could use it.

Wow. You guys are quick.

Thanks for the clarification. Makes sense.

So, that would mean a DAC amp would also be very useful for those that use their laptop for audio production?

For this use, the DAC amp would absolutely be preferred and in each of the cases you discuss would be expected to give a significant improvement in sound quality over the headphone out of the laptop. There are two reasons for this: 1) the DAC sections of the amps you name are far better than the sound card of most laptops, and 2) you are doing the conversion of sound outside the laptop and away from all the internal electrical interference.

I am not however comparing the amp section of any specific DAC amp with any specific non-DAC amp. I am nonetheless confident that even the finest portable amp will be a disappointment when used with the inferior headphone out of most laptops.

Definitely.
The headphone out of a laptop amplifies the signal. So connecting a headphone out to an external amp will amplify the signal twice, which is really bad. You'll get more distortion. What do you need is to connect a line-out to the amp. If your laptop doesn't have a line-out, that's where the external USB DAC comes in. So the DAC will convert the digital signal to analog. And then you'll connect the DAC, non amplified, line-out to the amp.
If you're using a DAC/AMP combo, you'll be provided by a headphone out directly ...

The headphone out of a laptop is bad because it is bad, not because of dual amplification. Does double amping increase distortion? Yes, nominally. But many sources including a lot of beloved standalone dacs amp their line out signal with opamps, and everyone who has a separate preamplifier (a real one, that is, and not just a switchbox) in their home system does the same. Nonamped line outs can be great, but they are not an end-all. This is a head-fi myth that has been growing in the last few months and needs to be nipped in the bud.

question

Hi I have been using the hornet as my portable amp with the 5G ipod as my source with the triple fi. But I find that the difference in the sound generated from triple fi between amp and unamp is minimal.

Your internal soundcard gets normally bypassed. But you can get noise from your computer. You don´t get EMV form your computer in the DAC. But you can get hum through the USB cable.

The only easy solution for that is to use optical out.

hey I'm looking around for my first budget portable amp

How does the PA2v2 compare with the Xenos 0HA-RHP? I'll most likely get one of these, unless there is a better alternative within the same price range.

just got a T2

Out of the box - very obvious improvement in dynamic range, clear highs, deeper lows with iPod 4G, ALO Cryo Dock and various inexpensive cans ( SR-60, Senns 555, less so with Etys ER-4P). Can't compare with other amps (noob here) - this is my first. Waiting for expert's opinions on this tiny gadget. Cheers.

$149 is a bit too much of a stretch for me. The highest I'll probably be able to go is around $100. I think I may be going with the iBasso T2.

I wasn't impressed with the pa2v2. it was too bassy for me.