Would this be able to drive my Senn HD6XX? They are the only headphones I have that are difficult to drive. Sometimes I like to sit in my backyard and it'd be nice to not have to drag out my whole amp and the extension cords too. I almost bought the NX4 recently but figured it was too expensive. Would this be worth it for me?
cwelton17Full disclosure, I don't have this particular amp, so I'm making an educated guess based on one I do have - the FiiO A3. Even then, I suppose the answer depends upon your audio source and just how loud you like your music to be in the first place.
I plugged in a few numbers into the headphone power calculator here (https://www.headphonesty.com/headphone-power-calculator/) and found that a Sennheiser HD650 (6xx should be identical) is green-lit for use with my FiiO A3 at 110dB-SPL. Personally, I found that this pushed a bit too close to the upper limit of the A3. It's plenty loud, but the amp starts to sound strained when maxed out like this. Rolling it back a little sounds better to me and is still more than loud enough for my general listening needs (though I might want a little extra power if I was specifically trying to rock out at what I would consider "loud" volumes). Sources I tested were a FiiO X5iii and Shanling m0, both hovering around 80-85% max volume.
FiiO lists the output power of the A3 at 270mW @32ohms (doesn't clarify per channel) vs. the NX3s at 545mW x 2 @32ohms. So minimally, the Topping will be twice the power (or about a +3dB gain), and if the FiiO isn't producing that power per channel, then it's closer to 4x (or about a +6dB gain). For reference, most people consider +10dB to be twice as loud perceptually. So I'm guessing the bump won't be massive, but still fairly significant.
That means (for my ears specifically): the Topping will have plenty of power to get my Sennheiser 6xx's as loud as I'd want to listen and still have a little headroom to spare. My preferred listening volume may not line up with yours though, so your mileage may vary.
It might not be the most straightforward answer, but hopefully that helps you come to a decision.
shorkordeSo sounds like the NX3 is like the minimum I'd need for a pair of 6XX basically? (Another commenter said the NX3 falls just short) I'm looking at the NX4 too but I'm really not expecting to use this device that much so that's why I'm leaning towards the NX3 since it's $100 cheaper. I'll have to check out that power calculator later!
cwelton17If I had to guess, I think this specific amp would be enough power for you and not just barely scraping the minimum but again; I'm basing that on the levels I was getting from my A3.
Also (just in case), be careful in terms of what reviews you are reading. Topping makes both an NX3 and this amplifier: the NX3s. The NX3s has notably more power; so if the comment you read about the NX3 falling short refers to the older/original NX3, it may be misleading you in terms of what the amp is capable of.
cwelton17This amp is powerful enough for what you need. The 6XX needs about 2 Vrms to hit 110 dB. This little amp will output almost ~4 Vrms for 300 ohms so you should still have some headroom as well. I use a Fiio A5 when I need more grunt but even my iFi nano BL is able to push my 6XX's well and have headroom and it maxes out at ~3.7 Vrms.
shorkordeGood point about the NX3 vs the NX3s. Everyone except that one guy said the NX3s should be fine so I will jump on this one rather than the NX4. Thanks :)
cwelton17If you have an Apple product and want to save cash, don’t bother buying an external DAC, as the Cirrus Logic implementation in most or all Macs, iPads and iPhones ((even the lightning dongle) is of higher quality DAC implementation. then to save money just buy an external headphone amp if you need one, such as this one. I have no direct experience with this NX3s, but I own the lower power NX1s (amp only, No included DAC) and it is a very good headphone amp with enough headroom for the Hd6xx, so imagine what this NX3s may produce in similar circumstances...
cwelton17Don’t believe what every Peter Paul and John may comment... make up your mind by your own judgment...
The HD6xx produces 103db with 1v under 300 ohms. Therefore it needs merely 2,3V or 17mw to reach 110db under 300 ohms. The NX3s produces over 100mw under 300 ohms. Therefore, I let yourself conclude...
cwelton17The HD6xx has a high impedance but at the same time it is very efficient and easy to drive, producing 103db with only 1V. All you need under 300 ohms to produce 110db is 17mw (or 2,3V). So the NX3s with its rated 100mw output under 300 ohms is more than enough and still has sufficient headroom for peak transients over 17mw... Therefore there is no power issue for the NX3s paired with the HD6xx. Case dismissed.
cwelton17@PeteMtl knows about this stuff better than most here. Trust him/her. This little guy is a very decent pairing for the voltage hungry, yet efficient HD6XX. For a brand new portable amp with this price tag, you'll be pleased.
cwelton17I have 6xx with Nx3s.
On high gain, 50-75% volume drives them very loud depending on the source hw and source music.
source hardware is either iPad or Fiio BTR5.
The bass boost is handy too - use it all the time