Battle of Battery Operated Portable Headphone Amps

[jhaider]

Amir, you have a Headroom Bithead or Total BitHead, right? I'm curious to see how it stacks up.

 

[amirm]

Amir, you have a Headroom Bithead or Total BitHead, right? I'm curious to see how it stacks up.

I had the Airhead and I think Max (first gen stuff). Both are long lost as I kept them at work and after so many moves, lost track of them. The Airhead made a big difference relative to native output of my laptop at the time. We are talking late 1990s.

 

[ishmeister]

Oh please, don't go down the "op-amp rolling" hole. The default amp design is fabulous. Look at the graphs. The only thing you might do is bork something. The ability to roll op-amps is probably the reason they put a big impedance at the output, as insurance against silly substitutions. That, in turn limited the utility of using this otherwise fine amp with iem's. Pisses me off, they put that socket there.

Resist the Dark Side of the force

Lol yeah, it was more a casual observation as it is in the marketing for the device but hadn't been mentioned.

I'm interested in the amp for its portability for full size headphones around the house. My phone can power iems just fine.

I used to own a chord mojo which filled the same use case but the NX3s combined with the amazing dac prom the lg phone should outperform that £400 device looking at the measurements.

 

[mikehoopes]

Oh please, don't go down the "op-amp rolling" hole. The default amp design is fabulous. Look at the graphs. The only thing you might do is bork something. The ability to roll op-amps is probably the reason they put a big impedance at the output, as insurance against silly substitutions. That, in turn limited the utility of using this otherwise fine amp with iem's. Pisses me off, they put that socket there.

Resist the Dark Side of the force

Someone on a head-fi DX3 thread just attempted that, and apparently damaged the board beyond repair.

Amir has measurements from an amp-rolling exercise on the Topping D10, which has socketed OPA2134s for the output buffer stage.

https://www.audiosciencereview.com/...ng-replacing-op-amps-in-topping-d10-dac.4576/

There are much better places to flex your DIY muscles.

 

[rebbiputzmaker]

Lol yeah, it was more a casual observation as it is in the marketing for the device but hadn't been mentioned.

I'm interested in the amp for its portability for full size headphones around the house. My phone can power iems just fine.

I used to own a chord mojo which filled the same use case but the NX3s combined with the amazing dac prom the lg phone should outperform that £400 device looking at the measurements.

Did you current phone sound the same as the mojo?

 

[Roen]

You mean AC measurements???

Yup, as JohnB mentioned. Part of the draw of battery powered amps that have AC power is that they are effectively two different amps in one, depending on whether you've plugged it in or not.

I still wouldn't mind seeing NX3 and O2 on AC, even if the NX3 is poor. Data is still data.

 

[ishmeister]

Did you current phone sound the same as the mojo?

I did not compare them directly so it's hard to say. There's been a lot of nonsense talked and written about the Mojo. The amp in the Mojo is obviously more powerful than the phone. But I am satisfied with the phone with the exception of the headphone amp which doesn't quite have the power to drive the HE4xx or HD600 adequately for example (I listen to a lot of modern Jazz recordings that need volume).

The phone will output 2 volts in line out mode and coupled with the NX3s I assume would work well.

 

[rebbiputzmaker]

I did not compare them directly so it's hard to say. There's been a lot of nonsense talked and written about the Mojo. The amp in the Mojo is obviously more powerful than the phone. But I am satisfied with the phone with the exception of the headphone amp which doesn't quite have the power to drive the HE4xx or HD600 adequately for example (I listen to a lot of modern Jazz recordings that need volume).

The phone will output 2 volts in line out mode and coupled with the NX3s I assume would work well.

Besides a better dac the LGs are more powerful than a typical phone. I use a LG v20 as a dap with good results. Don't own very inefficient phones though, Fine with Philips x2, or HE400s. Use it the most with iSines which are imo better than many full size phones, and much much more comfortable.

 

[Johnb]

Lol yeah, it was more a casual observation as it is in the marketing for the device but hadn't been mentioned.

I'm interested in the amp for its portability for full size headphones around the house. My phone can power iems just fine.

I used to own a chord mojo which filled the same use case but the NX3s combined with the amazing dac prom the lg phone should outperform that £400 device looking at the measurements.

Did I sound opinionated? Oops. Yeah, I think that in the universe of portable amps, the Mojo's, the Dacports, etc, the NX3s is a gift at $60. OK, no dac included, but in a large number of usage scenarios where you accept a bit less power than a desktop........

 

[Johnb]

Besides a better dac the LGs are more powerful than a typical phone. I use a LG v20 as a dap with good results. Don't own very inefficient phones though, Fine with Philips x2, or HE400s. Use it the most with iSines which are imo better than many full size phones, and much much more comfortable.

Yes, wasn't the audio in the V20 one of the big selling points, and marketed as such as well? You lucky guys with flagship phones.

 

[rebbiputzmaker]

Yes, wasn't the audio in the V20 one of the big selling points, and marketed as such as well? You lucky guys with flagship phones.

Yes it features better audio. It is an older model, you can find them used for a decent price. I got mine on ebay.

 

[Roen]

Why is the SINAD so different between the two tests?

 

[amirm]

Why is the SINAD so different between the two tests?

Different input levels. One is 1 volt and the other 2. The latter lowers the effective noise.

 

[jaytrinitron]

Noting the big difference in battery vs. usb power in the performance of the nx3s, could something like this also happen with the nx4-dsd?

 

[Johnb]

If I understand

Noting the big difference in battery vs. usb power in the performance of the nx3s, could something like this also happen with the nx4-dsd?

Very good question. That's why I asked Amir to test the NX3s on usb power. At the time of the review of NX4 DSD, I had meant to ask Amir if he had done it on battery power, then forgot to. It has one of those double usb setups - one for dac, one for charging. The assumption is the second is to prevent any large draw from the host device. My assumption is that both dac and amp were to be powered continuously off usb, if desired.

Almost identical dimensions, I would imagine the internal switching power supply re-used an identical or very similar design in both units. However, I can see the design logic "who's going to use it while its charging?".

Maybe only Roen and I liked the idea of a mini desktop. It's not like you can turn the volume knob without holding the units in your hand. I I had a cell-phone stand picked out for use on a desk.

Hope that Amir can remember.........

 

[jaytrinitron]

If I understand


Very good question. That's why I asked Amir to test the NX3s on usb power. At the time of the review of NX4 DSD, I had meant to ask Amir if he had done it on battery power, then forgot to. It has one of those double usb setups - one for dac, one for charging. The assumption is the second is to prevent any large draw from the host device. My assumption is that both dac and amp were to be powered continuously off usb, if desired.

Almost identical dimensions, I would imagine the internal switching power supply re-used an identical or very similar design in both units. However, I can see the design logic "who's going to use it while its charging?".

Maybe only Roen and I liked the idea of a mini desktop. It's not like you can turn the volume knob without holding the units in your hand. I I had a cell-phone stand picked out for use on a desk.

Hope that Amir can remember.........

I actually have two nx4-dsds, one I use portably and the other has a loose USB connection due to my rough handling, and thus I always keep it plugged in as a desktop DAC. Once the battery is drained, the NX4-dsd will turn on its red light and not function. If it is then plugged in to USB power, it will still be in red light mode. Only once a few minutes have passed and you turn it off and on again does it again function properly. It continues to charge up and work at the same time. I'm not sure how the nx3s functions, but this leads me to believe that the nx4-dsd possibly ONLY uses battery power to function, which would be nice as we would avoid the problem the nx3s shows. However, it could just be that during the turn it off and on again stage it switches its power delivery to the USB while the battery charges. My desktop NX4-dsd which is always plugged in never goes into the red, so honestly I have no idea how power delivery functions on the nx4-dsd. It would be nice to know, so I would love a test and/or explanation from Amir or someone else.

 

[amirm]

Hope that Amir can remember.........

Sorry I don't.

 

[ryanmh1]

I'm going to provide a suggestion here (again) that would make these reviews more helpful for determining sound quality: 19+20kHz CCIF IMD tests, and also a 6kHz and 20kHz THD+N v power sweeps. These SINAD measurements and what-not are interesting, but I'm not convinced they say much about sound quality (and there seems to be an awful lot of focus on them). Particularly so since virtually all music out there is only CD quality anyway. Practically speaking, the most useful measurements being done right now are probably the THD vs power to see how much power the amps can crank out before clipping.

On top of proper IMD tests and high frequency power sweeps, CEA burst tests might be interesting to see if any of these portables have any extra gas in the tank on actual music. Just a thought. I don't mean to sound like I'm complaining. This stuff is incredibly useful and helpful. Thanks to a combination of digging through this site and RAA I just picked up the Xduoo XD-05 (https://reference-audio-analyzer.pro/en/report/amp/xduoo-xd-05.php#rw14). Just a hair less juice, but the DAC is built in, and pretty good. Plus, you can roll op-amps!

 

[Johnb]

Sorry I don't.

Sorry I don't.

To tickle your memory......I would kind of remember having to plug two USB cables into a device. Not so common a thing.

 

[amirm]

To tickle your memory......I would kind of remember having to plug two USB cables into a device. Not so common a thing.

My hazy memory is way beyond tickling.