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Best portable USB bus powered headphone amp

lsanbourne

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Jun 14, 2024
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Hello, I'm a classical audio engineer, often mixing audio on the go with headphones, with very minimal suitcase space (EU<->US travel).

Can someone recommend a USB bus powered headphone amp that I could use on the go, unlimited budget, and would sound as good as Grace m108 headphone out? Bonus points if it has balanced outputs and thus could double as a monitor controller at home.

Current recording setup: 8 Schoeps mics -> Grace m108 -> listening with HD600
Current home studio: RME UFX III -> 2 Neumann KH 120
Current hifi system: Cambridge Audio, Revel, fed by RME ADI 2, WiiM hockey puck that doubles as a streamer

I heard good things about JDS Element III, Fiio K9, Schiit Jotunheim, and iFi GO Kensei, but the formers don't have USB bus power (and often aren't even dual voltage), and the latter brand doesn't do well in ASR tests.

I considered Neumann MT 48 but have heard that the signal path design is not exceptional.

I'm open to spending whatever it takes!

Thanks again,
Larry
 
Last edited:
Bus powered with Balanced Line out + Headphone out:
  • Topping E1x2/E2x2
  • Khadas Tone2 Pro
 
Thanks, staticV3! How would you expect those to compare to something like Grace m108 or Grace m900? I'm skeptical that something so much cheaper would actually be superior.
 
Thanks, staticV3! How would you expect those to compare to something like Grace m108 or Grace m900? I'm skeptical that something so much cheaper would actually be superior.
Both the Khadas and Topping are fully transparent DAC+Amps, which means in this regard (noise, distortion, linearity) they cannot meaningfully be bested no matter the price or heritage.

If the hundreds of reviews by Amir have taught us one thing, then it's that in audio, price and quality are rarely correlated.
 
Thanks. Is there a page on the site where I can see how m108, m900, Topping E*x2, Khadas Tone2 Pro, Babyface, and UFX III score on the most important metrics?

I ask partly because Babyface is no slouch on the measurements (according to its ASR review), but I am finding it astronomically easier to mix with m108's headphone out than Babyface's. There's obvious stuff like stereo imaging being more precise, but also my ears are much better able to parse out fine details of reverb with m108's headphone out. So I'd like to learn where Babyface sits in the rankings and make sure I get a monitor controller (and the portable headphone amp at hand) that best it.
 
That’s interesting, do you have a source for that?
It came from the founder of a major mic preamp company that does not themselves sell a competing product. But I haven't asked for permission to post the name publicly, sorry for the mystery!!!
 
Is there a page on the site where I can see how m108, m900, Topping E*x2, Khadas Tone2 Pro, Babyface, and UFX III score on the most important metrics?
Here it is:
Screenshot_20260108-044933_Chrome.png

Enable Titles only and Posted by: amirm and you'll find his review of the E2x2, Tone2, Grace M900, and RME Babyface.
 
I was looking for rankings of all devices according to all the measurements…I have already read the reviews.
 
Hello, I'm a classical audio engineer, often mixing audio on the go with headphones, with very minimal suitcase space (EU<->US travel).

Can someone recommend a USB bus powered headphone amp that I could use on the go, unlimited budget, and would sound as good as Grace m108 headphone out? Bonus points if it has balanced outputs and thus could double as a monitor controller at home.

Current recording setup: 8 Schoeps mics -> Grace m108 -> listening with HD600
Current home studio: RME UFX III -> 2 Neumann KH 120
Current hifi system: Cambridge Audio, Revel, fed by RME ADI 2, WiiM hockey puck that doubles as a streamer

I heard good things about JDS Element III, Fiio K9, Schiit Jotunheim, and iFi GO Kensei, but the formers don't have USB bus power (and often aren't even dual voltage), and the latter brand doesn't do well in ASR tests.

I considered Neumann MT 48 but have heard that the signal path design is not exceptional.

I'm open to spending whatever it takes!

Thanks again,
Larry
Why not use a battery powered headphone amp that you simply connect to the headphone out of any sound card ?
 
My Macbook's sound card sounds bad, so I want something that replaces that. interface+DAC+headphone amp, bus powered.
 
Topping E2X2 but is only USB-C because of the power drawn.
Perfectly able to drive HD600.
 
@lsanbourne
If you only need a single mic input, then the E1x2 is worth considering as well.

It has the same DAC, ADC, and Headphone Amp as the E2x2.
 
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