Topping 4330354362 NX1s Digital HiFi Portable Headphone Amplifier (Black)

omg this thing is so adorable. It's about half the size of most portable amps. I bought it to add a bit of extra juice to my Sennheiser 558s and AKG K7xx after I traded in my V20 for a Note 8. The V20 had a built-in amp/dac that was more than powerful enough for the 50ohm and 62ohm impedance of the 558s and k7xxs, respectively. Now that I don't have the V20, I needed something that could give those devices a little extra juice.Pros1. Surprisingly powerful for such a little thing. One of the few portable amps under $150 that can get decent power to a 300ohm set of cans (24mW @300ohm, I believe, which is more than enough for volume, at least).2. It's small. Like surprisingly small. Much smaller than something like FiiO A5. The FiiO A5 has more power, but this thing is like half the size and it comes fairly close, actually.3. The volume knob feels nice.4. Comes with high and low gain modes as well as a bass boost switch. Nice!5. Charges relatively quickly.6. Rock bottom price.This is the best amp for under $50 in terms of pure power output.Cons1. None really.2. The output impedance is reportedly 3.5ohm. That makes this amp not great for sensitive, low impedance IEMs where the output impedance should be as close to zero as possible. This amp is for big ole over-ears, not IEMs.For the price, this thing is a steal or at least worth the risk. I didn't think I'd ever be buying a $40 amp, but here we are and this thing is impressive. There are better amps, obviously, but you have to pay more for them. This is great for audiophiles on a budget that need a little extra juice to power those headphones. I tried these with a pair of HD600s and they got LOUD. The 600s would benefit from even more power than this thing can provide, but this little thing will get you there in a pinch.

This little amp is amazing for both the cost and the quality for lower impedance phones/IEMs.The packaging was immaculate and very apple-like. However, my warranty card was blank in the 'inspected by..' blank, which isn't a big deal but shows their business isn't perfected.More importantly the audio quality is great for my iSine10 and my Massdrop X Noble IEMs. The performance is as good as my Schiit Fulla 2 but with a lower noise floor. That being said, it was not sufficient to drive Hifiman He400i type phones.TLDR: amazing value and quality for IEMs

After reading the mixed reviews on other small headphone amplifiers, I decided to treat myself to something better with the NX1s. I am an audiophile and, for the price, this headphone amp has exceeded my expectations.The packaging is elegant, and the amp comes with a variety of accessories, including a short male-to-male 3.5mm headphone cord, a short micro USB charging cable (same size as Android phones use), stick-on Velcro dots for mounting the amp, a couple large rubber bracelets for other mounting options, and a non-slip pad. I bought this to boost the signal into the AUX input for my vehicle's OEM stereo (2009 Toyota Tacoma). Without a volume boost, the gain of the car's AUX input is so low that any auxiliary music is faint, even at full volume. Using the Velcro tabs, I have the NX1s mounted discretely under the radio.So how does the NX1s sound? At full volume, max gain, and max bass boost there is no added hiss. I have not heard any distortion, although I suppose that it would start clipping if the input signal is too high. Amplification is clean, the high-gain boost is okay (I'd still like more but this will do), and the bass boost is reasonable without being boomy. A small LED illuminates when the amp is charging; I don't yet have enough usage to evaluate the battery duration. The volume control feels smooth, a nice potentiometer with an off position. The case is milled aluminum, very solid construction, about the size of a credit card and as thick as a pencil.There are two gain modes, low and high. The low mode doesn't seem to amplify much, if at all. The manual nicely includes spectrographs of the response levels for various settings, and indeed it show ~0db gain in low mode, with a slight bass rolloff below 50 Hz. Without the bass boost, the low gain setting is probably only good for reducing the bass response a bit. With the bass boost on, the low-end gain starts ramping up gently below about 200 Hz, reaching about +4.5 db at 20 Hz. If your headphones don't quite have the bass kick you're looking for, this feature can help.In high gain mode the added signal is about +9 db, which is not huge, but enough to give my anemic car stereo a sufficient level of ecstasy. The bass boost in high-gain mode ramps up the same, to about +13.5 db at 20 Hz. THD is mostly low, with a minor bump around 5 KHz.Overall, this is really nice headphone amp.

I have a set of Sennheiser HD 6XX headphones that I've been meaning to amp for a while now. They sounded pretty good, but my iPhone volume had to be maxed out to get anything resembling enough sound out of them. I put off getting an amp for about a year, and I read all sorts of reviews, compared prices. I'm not sure why I pulled the trigger with this one, but I'm glad I did! The Sennheisers sound even better now. I've also started using it with my Futuresonics G10 earphones, and I love them more than ever now.It's early on yet, so I can't comment on battery life or durability, but for the price, it's hard to be nitpicky. The build looks solid, and it's smaller than I thought it would be. The bass boost is nice, not too bloated on most things I've listened to thus far. And when it is too much, I switch it off and it still sounds great. I love having a more sensitive volume control than the iPhone allows, too. I don't jump from one volume to the next. I recommend this to anyone with up to 300 ohm headphones. Great bang for the buck.

Es el primer amplificador que compró. Sí se nota la diferencia de sonido en un Smartphone. Lo único malo, es que los elásticos son muy pequeños para poder colocarlo en un celular.

Ears aren't fine enough to do it justice. Sorry.

Sin duda por el costo del amplificador puedo decir que es muy bueno. Lo recomiendo ampliamente.