[mrspeakers]

 
Quote:

See I've been measuring the NFB12  as a standalone DAC and its distortion is relatively high,  not bad but surprisingly higher than even a decent tube dac.   But the key unique feature/design of this nfb12 is the inegration to the headphone amp and the complete absense of typical color adding negative feedback.   In other words after I was measuring the dac output I also measured the headphone out and the distortion spectra/level was the same,  even as the volume knob (power out) was turned up !  
 
This is the beauty of Kingwas's analog design in that the entire system is scaled as the volume knob is turned,   so that up to a point a change in volume does not equal a change the sound quality.   Thats one of the dirty secrets about most any gear you buy,  the dac output is attenuated then the amp with its fixed gain amplifying an attenuated signal has increasing distortion with input level.  Ever notice how most separate amplifiers sound "different" with a slight turn of the volume knob?   And many times you fight it trying to find that sweet spot where everything sounds good at the right volume?  
 

You can clearly hear the distortion when I run a simple 40Hz tone into my NFB-12.  There is pronounced distortion, at a level which I've never heard in other gear.  I haven't put it on a distortion meter, I don't have access to a quality device, but the distortion should not be audible like it was on my unit.  I use it in the office where I don't pay deep attention to sound, and it's certainly OK for the $, but I have to say I was disappointed to hear that kind of issue in a discrete device with value-audiophile aspirations...
 
 

 

[turimbar1]

I took a look at the inside of mine and there is no way to change the filter, I am a little disappointed, but I knew it was a work in progress and still bought it, so yeah, annoying, but I cant fault kingwa. 
 
does anyone know what the default filter is? 
 
edit: 2x brickwall filter? well that is just ******* great, that looked like the worst of the bunch.

 

[eclipes]

I believe its the 2x Brickwall filter.
 
Quote:

I took a look at the inside of mine and there is no way to change the filter, I am a little disappointed, but I knew it was a work in progress and still bought it, so yeah, annoying, but I cant fault kingwa. 
 
does anyone know what the default filter is? 

 

 

[shadowlord]

you should be able to change filters on the old unit as well.
But it includes soldering.

 

[turimbar1]

really? the layout looks a bit different, I really dont want to go at it just based on sight.

 

[captouch]

Quote:

you should be able to change filters on the old unit as well.
But it includes soldering.

Perhaps one time, but not back and forth among the 9 settings easily unless you rigged some external switches.  I think you have to desolder and lift some IC pins at the very least.
 

 

[Ken Rosenberg]

Please delete.

 

[glenda]

Quote:

Sorry for the noob question, but how would I connect the NFB-12 to a CD player?
 
I'm guessing I could either use the optical out, or have a dual RCA cable that terminates to one, which then connects to the coaxial output. Could someone please correct me if I'm wrong

 
just plug the cdp opt-out to the NFB-12 opt-in and turn the knob to OPT.
 
  It sounds like your CDP doesn't have a coaxial out, do not do the other thing you came up with,

 

[Ken Rosenberg]

Please delete.

 

[Tilpo]

Thanks, I'm still very new to this. Is there a noticeable sound quality difference between optical and coaxial?

No. There is a theoretical difference, but it should be far from audible.

 

[tme110]

It is easier to lock on to very high-res (like 24/192) with COAX but you won't notice a difference soundwise. 
 
There would be a sound difference if you connected it from the CDP RCA outputs but the -12 doesn't have connections for that anyway. ie, it has to used as a DAC which is what you would want anyway.

 

[ac500]

When did the new version NFB12 come out, and how do I tell if I have it? I bought mine late July.

 

[Brooko]

Quote:

When did the new version NFB12 come out, and how do I tell if I have it? I bought mine late July.

The new iteration has the changeable filters (see pic) - just pop the lid, and have a look.
 

 

[ac500]

Ok I'll check when I return from my trip. Although I just remembered my NFB12 being packaged with a little zip lock bag of the black jumper things. Hopefully that's a good indication that it's the new version.
 
What's the generally accepted best filter setting?
 
Also I don't understand the FR graphs for each setting on Audio-gd's site. Frequency only spans from 0 to 1? What is frequency here, HZ??

 

[eclipes]

yup those spare black jumpers are for the new version. So far I've heard that the 8x minimum phase apodising is the most popular filter but you're limited only to 48khz. I personally like it a lot, great clarity, especially music dealing with guitars. But for the sake of versatility, I switched to the 4x linear phase soft knee which could support up to 24/96, sounds good, not as much clarity compared to 8x and with bit of warmth. 
 
Quote:

Ok I'll check when I return from my trip. Although I just remembered my NFB12 being packaged with a little zip lock bag of the black jumper things. Hopefully that's a good indication that it's the new version.
 
What's the generally accepted best filter setting?
 
Also I don't understand the FR graphs for each setting on Audio-gd's site. Frequency only spans from 0 to 1? What is frequency here, HZ??