[Gloomy Moonie]

What headphones are you using?

AKG K7XX and K272.

 

[Kamakahah]

AKG K7XX and K272.

Interesting. I don't get any hiss when running the K7XX through the NFB-15.
I am surprised that you don't notice a difference going from the laptop amp to a dedicated desktop amp. Even poor quality source files should sound different, usually in a bad way.

Perhaps the hiss is a sign that something needs adjusting in the setup. I'd try troubleshooting that first to see if that changes anything for you.

A couple more questions:
Is it hooked up to your laptop via USB?

What program do you use to play the media? Are you using WASAPI or ASIO if using Windows?

What format/res source files? Specific examples?

Have you tried any other inputs like the optical or coaxial? If yes, do you get the hiss from those?

 

[Jakkal]

  Got my NFB-15 a couple of days ago. After long hours of tedious listening, I have to say that I honestly cannot tell the difference between my Sony laptop and the NFB-15. Tracks that are "efficient" enough to have enough volume through the laptop sound the same too. This begs the question of whether I'm missing something, and the vast majority of posts that report otherwise doesn't make it any easier.
Another thing is hiss, which is very noticeable after 12-14 o'clock, for both low and high gain, funnily enough. It's unfortunate that I had to discover this myself, but with the gain on high I'm far from the hiss having any influence on the music. Is this something that's normal across amplifiers?
This being my first amp/DAC combo, I'm starting to get the attraction of tube amps, because right now I'm sitting and wondering whether I've bought a solid state amp for $300, that sounds the same as my 5 year old laptop.

 
This are my findings for NFB-15 as well, except it sound a bit worse than my on-board audio, more lifeless. Also I have posted that I hear hiss on low and high gain after 12 o'clock. Add to that horrible customer service and bad drivers with blue screen issues and you'll understand why I don't recommend NFB-15.
If you look for a tube amp, check Project Ember, but you may want to wait a bit, because a new version is coming with more gain options.

 

[Change is Good]

  Got my NFB-15 a couple of days ago. After long hours of tedious listening, I have to say that I honestly cannot tell the difference between my Sony laptop and the NFB-15. Tracks that are "efficient" enough to have enough volume through the laptop sound the same too. This begs the question of whether I'm missing something, and the vast majority of posts that report otherwise doesn't make it any easier.
Another thing is hiss, which is very noticeable after 12-14 o'clock, for both low and high gain, funnily enough. It's unfortunate that I had to discover this myself, but with the gain on high I'm far from the hiss having any influence on the music. Is this something that's normal across amplifiers?
This being my first amp/DAC combo, I'm starting to get the attraction of tube amps, because right now I'm sitting and wondering whether I've bought a solid state amp for $300, that sounds the same as my 5 year old laptop.

 
Originally Posted by Jakkal /img/forum/go_quote.gif
 
 
This are my findings for NFB-15 as well, except it sound a bit worse than my on-board audio, more lifeless. Also I have posted that I hear hiss on low and high gain after 12 o'clock. Add to that horrible customer service and bad drivers with blue screen issues and you'll understand why I don't recommend NFB-15.
If you look for a tube amp, check Project Ember, but you may want to wait a bit, because a new version is coming with more gain options.

 
Wow, you guys must have some serious on-board audio...

 

[Brooko]

Optical for me.
 
No hiss
 
Sounds fantastic
 
What are you guys driving to be using high gain over 12 oclock on the pot?  Or even low gain?  The only time I use high gain past 12 is using passive monitors - and again, no hiss, wonderful sounding.  Even my T1s (600 ohm) I mostly use low gain and don't go past 12 .......
 
@Gloomy Moonie - I'd also be keen to know how you're setting yours up .......

 

[Change is Good]

  Optical for me.
 
No hiss
 
Sounds fantastic
 
What are you guys driving to be using high gain over 12 oclock on the pot?  Or even low gain?  The only time I use high gain past 12 is using passive monitors - and again, no hiss, wonderful sounding.  Even my T1s (600 ohm) I mostly use low gain and don't go past 12 .......
 
@Gloomy Moonie - I'd also be keen to know how you're setting yours up .......

 
^This! I have yet to use a headphone past 12 O'clock on this thing. The power hungry K612 was probably the closest, on low gain at that...

 

[Brooko]

Wondering if both have volume close to zero out of PC, and turned up high on NFB-15?  That might explain the poor signal to noise ratio.  Not the fault of the NFB unit in that case - just poorly set-up?

 

[BlueRequiem]

We'll have to wait to hear from Gloomy Moonie to know if there is a setup problem somewhere. I know that for nearly all of my headphones I have to use high gain to adequately drive my headphones, and for a few I can have it maxed out without it properly driving them (600 ohm dynamic and 400 ohm electret-dynamic hybrid vintage AKG's). That said, I don't have any problem with noise or hissing with my unit.

 

[TeddyK]

What do you think about the Headphone amp of the Audio-GD NFB-15 ?
 
Same quality than a JDS LAB O2 ?

 

[BlueRequiem]

The headphone amp on the NFB-15 is actually quite good, it's just that it doesn't swing quite enough volts to properly drive some really inefficient headphones. It actually does a fine job with quite a few 600 ohm cans, which is more then can be said for the O2.  If you take the NFB-15 to full volume you won't get distortion from the amp (although you may blow out your headphones, not to mention eardrums), the O2 on the other hand cannot be pushed to max gain without clipping and distortion. The O2 is fine for a small amp, it just can't compete with the NFB-15 in either quality or power. That said, I can't haul around an NFB-15 with my laptop while the O2 is quite easy to throw into a laptop bag.

 

[TeddyK]

Thanks for your return.
I have a DT-990 250 ohms, easy to drive, and it's especially the Headphone amp quality of the NFB-15 i'm looking for.
.

 

[Gloomy Moonie]

Interesting. I don't get any hiss when running the K7XX through the NFB-15.
I am surprised that you don't notice a difference going from the laptop amp to a dedicated desktop amp. Even poor quality source files should sound different, usually in a bad way.

Perhaps the hiss is a sign that something needs adjusting in the setup. I'd try troubleshooting that first to see if that changes anything for you.

The first thing I did was of course address Kingwa with this issue, to which he replied with saying that it shouldn't be audible on normal listening levels. 
This leads me to conclude that it the hiss is normal to some degree, which does not correspond with a good number of you who claim that there is no hiss. I don't think it is necessary to continue with depicting the possible explanations, as I feel that I've made my point.
Moving on.
 

   
What are you guys driving to be using high gain over 12 oclock on the pot?  Or even low gain?  The only time I use high gain past 12 is using passive monitors - and again, no hiss, wonderful sounding.  Even my T1s (600 ohm) I mostly use low gain and don't go past 12 .......
 
@Gloomy Moonie - I'd also be keen to know how you're setting yours up .......

Never have I said that I use it on 12 o'clock on high gain, I merely notice it starting from 12 o'clock, for both gain options. This is why I prefer using high gain, as I don't come nearly as close to 12 o'clock as with low gain, on which I sometimes go past that, giving me a reason to be concerned.
 

  Wondering if both have volume close to zero out of PC, and turned up high on NFB-15?  That might explain the poor signal to noise ratio.  Not the fault of the NFB unit in that case - just poorly set-up?
 

No.

 

A couple more questions:
Is it hooked up to your laptop via USB?

What program do you use to play the media? Are you using WASAPI or ASIO if using Windows?

What format/res source files? Specific examples?

Have you tried any other inputs like the optical or coaxial? If yes, do you get the hiss from those?

• Connected via the included USB cable.
• Foobar2000, see settings here.
• I attempted a blind test on this one, so bear with me:
  1. Method: I've downloaded a 320 kbps and a 24bit 192kHz version of each of the two tracks available here, and using my K7XX and K272 headphones, tried to guess which is which, 10 times for each pair.
  2. I've tried setting playback to random and shuffle, but in nether of them can the same track be played again. Fortunately randomly clicking on Playback>Random proved to be an effective measure, so I've set a shortcut for that in keyboard settings.
  3. To control for volume I've set the Processing to "apply gain" under ReplayGain in Playback preferences.
  4. After each guess I was checking which file res. I was listening to to write it down, as doing that after the whole 10 trials would have been more difficult than I can tolerate, and playback statistics weren't of any use.
  5. In between each trial, I've had one "unblinded" listen, so as to reduce confusion. After that I've manually skipped (using the above shortcut) an indefinite amount of times, to reduce the expectation bias at least to some degree.
  6. The screen was nowhere in my field of vision.
  7. The headphones were worn for a few minutes prior to testing with the tracks playing, for adaptation purposes.
  8. At times where I knew I wasn't analyzing but merely guessing weren't included.
  9. Initial results: Track #1: K7XX - 3/10 (W,W,W,W,R,R,W,W,R,R). Track #2: K272 - 8/10 (R,R,R,R,R,R,W,R,W,R); K7XX - 6/10 (R,R,W,W,R,R,W,R,W,R). R - right, W- wrong.
  10. On my last set of trials, which was with the K272's, I've thought of a method to compensate somewhat for the capacity of our auditory memory, which was to do everything as described above, but make the guess not on the first, but on the following track, so as to allow for some context.  And what do you know, my the results changed drastically.
  11. 4'th attempt results: K272 - 10/10.
  12. Conclusions: Just look at what lengths I've went to to arrive at that last result, 'nuff said. Seriously though, I admit that at first I thought that I won't find any difference whatsoever, and rightfully so. But even though technically there is a perceivable difference, it doesn't mean it's significant. Maybe with better gear it is more easily discerned, but on a practical level I've made it clear, at least to myself, that there is no point in hi-res. Not to even mention all of those expensive DAP$.
  13. Comments: First of all, the obvious volume difference between the versions. Knowing this alone should be enough to get a sense of the validity of the difference between high and low res.. I've been keeping it in mind after volume adjustment as well, which could have contributed to my results.  Then again, it is said that the increase in volume is perceived as an increase in quality, maybe it works the other way around as well . Second is that despite all my efforts, those comparison attempts still felt like guesswork, even at that last attempt.
• Haven't tried other inputs yet, which could change in the upcoming weeks. That is, if I won't return the unit before that. 

 
The only explanation I can think of as to why I don't hear any difference, aside from not having the "audiophile ear" of course, is that the NFB-15's DAC is off. But honestly it just doesn't sound plausible, no matter how I look at it.
 

   
This are my findings for NFB-15 as well, except it sound a bit worse than my on-board audio, more lifeless. Also I have posted that I hear hiss on low and high gain after 12 o'clock. Add to that horrible customer service and bad drivers with blue screen issues and you'll understand why I don't recommend NFB-15.
If you look for a tube amp, check Project Ember, but you may want to wait a bit, because a new version is coming with more gain options.
 

Too bad I didn't hear that before buying it. Having the blue screens once or twice a day, but that's the least of what's wrong with the driver. Ever since I've got the NFB-15 my computer is much slower, sometimes I have extreme stutter when I watch Youtube videos on x2 speed, and Foobar's spectrum visualization has low framerate. Oddly enough, when I switch to, say, ASIO4ALL, the framerate goes back to normal, but all other "symptops" remain. Maybe it's a good idea for anyone who's still on the fence after reading this to just install the driver and see how their system behaves.

 

[Kamakahah]

@Gloomy Moonie
 
Well, I can't say that I suffer from any driver issues. Haven't had any difference in computer performance or any BSODs. 
 
I went back and did some testing out of a few cans. Without music playing, I begin to hear the hiss somewhere between the 12 to 1 o'clock mark for both gain settings. 
Listening to most tracks at non-tympanic membrane destroying levels it's not an issue.
However, I switched to some older orchestral tracks as well as some quieter ambient tracks that permitted me to go above the 12 o'clock mark. Now, I likely still wouldn't listen to them this loud but it wasn't painful at all. At that point I could pick out the hiss. 
I tried it through foobar with WASAPI using USB as well as Spotify/Sound Cloud streaming with optical. 
 
 
A few more notes. I never hear it while gaming, movies, or TV with the K7XX, HD598, Sony MA900, or Senngrado. 
 
I unplugged the source while testing as well and the hiss remained. So, it's not coming from the source - Not that I expected that to be the case. 
Not a lot you can do without changing the internals. I suppose you could add some resistance to the amplifiers output. Maybe make/buy an adapter with a little resistance in series. This could/will affect the sound depending on the cans you're using and the resistance added. 
 
So it's unlikely to affect me for ~85% of my listening. That said, the other 15% could be affected depending on how loud I care to listen to my quieter tracks. 
Unfortunately, I've sold off all my my planar cans and don't own any high impedance ones to test. 
 
I'm glad your comments made me dive in a little further to investigate. I was already planning on picking up an Ember to compliment the setup, so depending on the outcome of that I might just switch to the Ember + Modi2 Uber.  For not, it's not a pressing issue. 
 
(edited out quote for space)

 

[Brooko]

Hmmm - no hiss at all for me (mind you it is an NFB-12 rather than NFB-15).  Guess I was just lucky?

 

[Gloomy Moonie]

@Kamakahah I suspect it just depends on the system. Given that my laptop is pretty old, it's less likely to survive such an inefficient driver.
Thanks for the providing a possible fix, but I have no time nor interest to fiddle with that right now. I'd much rather go with the M2&M2, which were the second best option when I was deciding which combo to get. A few things that pushed me away from it are, first of all, internals - can't say I'm savvy in electronics, but I was under the impression that this simply cannot be better than this. Also American companies aren't allowed to under-declare by law, which did a pretty good job at deterring me from getting it, since import taxes are pretty steep where I live.
 

Edit - scratch that, I need sleep.