[jodgey4]

A little update on the noise issue, the new drivers have fixed some noise from USB input. I'm still hearing distorted music at low volumes from digital inputs with IEM's, though I had not listened for it with full sized headphones other than the only semi-sensitive LCD-2's. This distortion seems to only be a problem with sensitive IEM's. Kingwa is now aware of the issue, and we are now hopefully working on a solution. The hiss is also only a problem with IEM's, and a non-issue with anything full sized. I feel like I was perhaps a little too non-descript in my initial post, and feel obligated to clear things up. I am still disappointed in how IEM's work with this amp as we currently stand. I'll keep everything updated here.

 

[conquerator2]

Went for C2 instead :]

 

[KnightThe2nd]

  A little update on the noise issue, the new drivers have fixed some noise from USB input. I'm still hearing distorted music at low volumes from digital inputs with IEM's, though I had not listened for it with full sized headphones other than the only semi-sensitive LCD-2's. This distortion seems to only be a problem with sensitive IEM's. Kingwa is now aware of the issue, and we are now hopefully working on a solution. The hiss is also only a problem with IEM's, and a non-issue with anything full sized. I feel like I was perhaps a little too non-descript in my initial post, and feel obligated to clear things up. I am still disappointed in how IEM's work with this amp as we currently stand. I'll keep everything updated here.

finally i can try to use FAD heaven-s (if i remember correctly its 16 ohm, 100+ db sensitivity) with NFB-28 and yeah i can heard the noise, then i tried fischer audio DBA02 mkII (48 ohm, i forgot the sensitivity) noise get quieter, last i tried low end portable beyer DTX501P (32 ohm, forgot the sensitivity), its dead silent no noise at all.

 

[BALANCEATOR]

  A little update on the noise issue, the new drivers have fixed some noise from USB input. I'm still hearing distorted music at low volumes from digital inputs with IEM's, though I had not listened for it with full sized headphones other than the only semi-sensitive LCD-2's. This distortion seems to only be a problem with sensitive IEM's. Kingwa is now aware of the issue, and we are now hopefully working on a solution. The hiss is also only a problem with IEM's, and a non-issue with anything full sized. I feel like I was perhaps a little too non-descript in my initial post, and feel obligated to clear things up. I am still disappointed in how IEM's work with this amp as we currently stand. I'll keep everything updated here.

 
Hello.

Me too makes me mush with my low impedance headphones Nfb-28.

In a link from a review of Spain who hung further back I think what they said too.

I do not remember that ad was.

regards

 

[phandrew]

I'm thinking of upgrading to the NFB28 (2014) soon but I have a question. Is it really worth upgrading the TCXO for $40USD?

 

[conquerator2]

I'm thinking of upgrading to the NFB28 (2014) soon but I have a question. Is it really worth upgrading the TCXO for $40USD?

What are you upgrading from?
But yes the TCXO are considered a worthy upgrade especially for the relative little they cost.
You're upgrading the DAC chip and USB chip, which are both very important if you use them, just like the amplifier part.

 

[KnightThe2nd]

  I'm thinking of upgrading to the NFB28 (2014) soon but I have a question. Is it really worth upgrading the TCXO for $40USD?

yup in my opinion its a worth upgrade, the sound became more refined, a bit softer without sacrificing detail, the biggest difference is on vocal though, its getting livelier

 

[phandrew]

I'm upgrading from the nfb3.1 and tube amp so the nfb28 will be an all in one package for me.

If I upgrade the usb when the TCXO then there's no point using toslink correct?

 

[conquerator2]

I'm upgrading from the nfb3.1 and tube amp so the nfb28 will be an all in one package for me.

If I upgrade the usb when the TCXO then there's no point using toslink correct?

I think so. People say it sounds the same or very similar.

 

[bbfoto]

A little update on the noise issue, the new drivers have fixed some noise from USB input. I'm still hearing distorted music at low volumes from digital inputs with IEM's, though I had not listened for it with full sized headphones other than the only semi-sensitive LCD-2's. This distortion seems to only be a problem with sensitive IEM's. Kingwa is now aware of the issue, and we are now hopefully working on a solution. The hiss is also only a problem with IEM's, and a non-issue with anything full sized. I feel like I was perhaps a little too non-descript in my initial post, and feel obligated to clear things up. I am still disappointed in how IEM's work with this amp as we currently stand. I'll keep everything updated here.

 


Thanks for the update. Had just sent you a PM and then saw this post...haven't been around in a while due to travel/work. My offer still stands. Keep me posted. Thanks!

 

[bbfoto]

Check my profile for the phones I'm using. Out of my collection hiss can be detected by the tg334, but only on some volume setting: it would have a slight hiss on volume 5, 6, 7 but not at 8, then again on 9, 10, etc.... so I would pick the points where it is pitch black to use with it (not really that often). The tg334 is ultra sensitive even by iem standard and we sometimes jokingly call it the I use detector. None of my other phones/iems pick up hiss.

 


Thanks for this information. And sorry that I didn't notice the HPs you have in your profile, as I was perusing with a "mobile" browser which doesn't display that for some reason.

It's very interesting about the noise only at the particular points on the volume level. Must have something to do with the gain structure and how the stepped-resistor ladder is implemented. Weird.

 

[bbfoto]

ok here is the update, tried NFB-28 with MacBook and the result is the same, first half-sec of songs got truncated, and here is the explanation from kingwa

"The DAC include DSD playback ability must had the mute design.
Otherwise while playing between PCM and DSD music, will had quite loud switch noise produce by the ES9018 , or other DA chip.
In NFB28 we are applied the relay mute design for avoid effect the sound quality.
It is mute 0.5 second for avoid the DSD / PCM switch noise.
Kingwa"

about the distorted sound after 3hours of continuous use, he suggested that i send the unit back to him for inspection
kudos to kingwa for excelent afterales service

Ahhh...this makes sense (the DSD/PCM muting). Thanks for posting Kingwa's explanation. Still, it is an unfortunate side-effect. Now I'm just trying to figure out why I never noticed this! :-/ I guess that I didn't use the USB all that much, though...really just to test the DSD playback and I don't have that many of them. Most of my regular sources use the optical, coaxial, or analog inputs via an Arcam rBlink Apt-X Bluetooth receiver.

I guess that it is both good and bad that we are discovering all of these little, but important details. Perhaps it becomes more of a problem when trying to produce an "all-in-one" Swiss Army Knife device like the NFB-28. There are so many different use-case scenarios and possible configurations! Luckily Kingwa is very responsive to his customers. Kudos for that!

@ KnightThe2nd, is the "distorted sound after 3 hours of continuous use" via the USB a problem with BOTH the PC/Windows AND Mac laptops?

 

[conquerator2]

I posted this in the Compass thread, maybe some will find it helpful:
FYI, I've been contemplating whether to go with the Compass2 or NFB28 and I've discussed this with Kingwa to a great length (much kudos to him). I've come to the following conclusions:

- In single-ended use they're very similar
- The NFB28 has the benefit of a balanced design, enabling one to use balanced inputs (RCA vs XLR related differences) and balanced output (which in theory should make the headphone sound a bit better and more controlled + the balanced design of the amp, which should make the amp section a bit better)
- The balanced output is basically the one thing that makes the NFB28 better (single ended vs balanced termination)
- NFB28 uses digital relay controls and digital volume control, which he says is better even sonically, I personally like ALPS analogue volume pots just as much and not really sure about sonic merits
- NFB28 uses an R-core transformer while the C2 uses a smaller 'high quality' 45W transformer. No idea if that makes a difference
- DAC section is identical
C2 has a line in through an op-amp, NFB28 has a direct input.
- With the stock op-amp, difference should be small if any (my guess)
- C2 can roll DACs and op-amps for line in, NFB28 cannot
- Both have plenty of power to drive everything short of the HE-6

In the end because I went with the Compass because going balanced would mean further investments (cables or even sources or converters) and without using the balanced output the difference is 'slight' since the DAC and single-ended amp sections are ialmost dentical. (C2 is slightly more powerful even).

In conclusion if you are ready for balanced get the NFB28 (or upper models), if you roll single-ended (I only utilize the USB in and line in and a SE output is more viable for me cause most headphones come like that... Retermunatiom or balanced cables = money over budget...) spring for the C2.

Both amazing units for the price

 

[KnightThe2nd]

Ahhh...this makes sense (the DSD/PCM muting). Thanks for posting Kingwa's explanation. Still, it is an unfortunate side-effect.

Now I'm just trying to figure out why I never noticed this! :-/ I guess that I didn't use the USB all that much. though...really just to try DSDs. Most of my regular sources use the optical, coaxial, and analog in via an Arcam rBlink Apt-X Bluetooth receiver.

I guess that it is both good and bad that we are discovering all of these little, but important details. Perhaps it becomes more of a problem when trying to produce an "all-in-one" Swiss Army Knife device like the NFB-28. There are so many different use-case scenarios and possible configurations! Luckily Kingwa is very responsive to his customers. Kudos for that!

@ KnightThe2nd, is the "distorted sound after 3 hours of continuous use" via the USB a problem with BOTH the PC/Windows AND Mac laptops?

yeah after i got that email from kingwa i tried to search about DAC that have DSD support, without that muting system, we will get some unpleasant noise when we play PCM file and then change to DSD file, vice versa. thats why player such as jriver has this option "play silence at startup for hardware synchronization"
 
that "distorted sound after 3 hours of continuous use" i only tried with windows laptop, i dont have MAC laptop in my possesion, i use my friend's when i tried nfb-28 with MAC laptop, and of course i cant use his laptop for too long
 
btw i got my new unit yesterday, beside the DSD/PCM muting (a design that i can accept now), this 1 seems ok, FYI i live in guangzhou right now, about 2 hours from kingwa's factory

 

[dasiyes]

I've just got my NFB-28 unit and would like to say thanks a lot to kingwa for his responsiveness and excellent customer service.
I have the device hanged on both my MBP and Intel NUC (ubuntu minimal with XBMC) and listened for more then 3 hours on each of them, but did not notice the issue yet. The input is USB with the upgraded TCXO.