Audio-GD NFB-12
Jul 12, 2012 at 6:12 PM Post #2,056 of 2,278
I was assuming he meant digital out from PC via coax (RCA connectors).
 
Jul 12, 2012 at 6:15 PM Post #2,057 of 2,278
Quote:
I was assuming he meant digital out from PC via coax (RCA connectors).

Well yeah, but from my experience, and such a short and not in depth post. A rather longer post clarifying things is better. I have truly dealt with people in other area's that I thought would get what I meant as it was a bit obvious(Cable A that says it fits into hole B) have left me in despair. I have had people trying to start up a computer that wasn't plugged in because I didn't tell them to plug it in, and people with no sound comming out of whatever because I didn't tell them to plug the cable back in when I told them to "test it out".
 
Just my 2cents realy.
 
Jul 12, 2012 at 8:53 PM Post #2,059 of 2,278
Quote:
Sorry for the confusion.  I meant the stereo analog RCAs inputs, so you can input non-digital signals.  The Compass and Fun had them.
 

Ah - no unfortunately no line-in on the NFB-12.
 
Jul 12, 2012 at 9:01 PM Post #2,060 of 2,278
On the 12.1 looks like you can replace the coaxial or optical with a BNC connector.  Is that a digital or analog input?  I wonder if I could somehow feed an analog signal in there if I needed to?  I don't need the option often, but it's nice to have.
 
 
Jul 12, 2012 at 9:05 PM Post #2,061 of 2,278
Quote:
On the 12.1 looks like you can replace the coaxial or optical with a BNC connector.  Is that a digital or analog input?  I wonder if I could somehow feed an analog signal in there if I needed to?  I don't need the option often, but it's nice to have.
 

There is no analog signal input, just digital through USB, COaxil or optical S/PDIF
 
Jul 13, 2012 at 12:05 AM Post #2,063 of 2,278
Quote:
On the 12.1 looks like you can replace the coaxial or optical with a BNC connector.  Is that a digital or analog input?  I wonder if I could somehow feed an analog signal in there if I needed to?  I don't need the option often, but it's nice to have.
 

 
It stays a digital input. SPDIF signals can be transferred trough just about any types of cables. TOSLINK, RCA, BNC, TRS, XLR, DB25... You could even use an Ethernet cable if you wanted to.
 
If you think the NNFB-12 lacks connectivity, check out AudioTrak's DR.DAC2 DX.
 
Audiotrack-DAC.jpg

 
Jul 13, 2012 at 9:59 AM Post #2,064 of 2,278
Thanks! Looking up the AudioTrak's DR.DAC2 DX also turned up the Grant Fidelity TubeDAC-11.  One of these is probably more what I'm actually looking for.
 
Now back to the NFB-12.
 
 
Jul 16, 2012 at 9:44 AM Post #2,065 of 2,278
I just bought one of these for my LCD-2's, hope I won't be disappointed.
 
Jul 17, 2012 at 6:43 PM Post #2,067 of 2,278
Well I hadn't thought of that. Asking technical information from a manufacturer and expecting an answer seems like an alien idea. 

But it worked! I received an answer, telling me which resistors to change, to what value, and what the result will be.

There's 8 2202 surface mount resistors in a line of 16 resistors between the dual DACs and the dual relays. 2202 is 22k 1%. Changing these with 47k resistors will lower the gain by 7dB.

Here's the line of resistors in question.



The other 8 resistors are 5.6k. They alternate, so there's 22k, 5k6, 22k, 5k6... etc. I'm guessing the 5k6 are for the high gain and the 22k for the low gain. Edit : Just received an email confirming the 5k6 are for the high gain.

So now all I need are 8 47k resistors in 1206 package. Changing these will be quite a challenge. :D


I received the 47K resistors yesterday. They had very little variations for 5%. Finding 8 within 100R was not a problem.

The modification went well, it took me about 2 hours. I removed the capacitors around the resistors to give more place for my iron. I think half of the original resistors were damaged during their removal. For a first time with surface mount, I think the result was good. Sadly though I don't have a good camera, so no pictures.

I'm currently testing it, and I can't hear a difference in volume. It's still too loud. The pot has no useful range, as higher is too loud and lower has bad channel imbalance. I'll have to contact Kingwa again.

While I had the board in hands, I studied it to confirm what I said about the line out: it's connected to the output of the amplifier. As in, there is no difference between the RCA at the back and the TRS jack at the front. There's a relay that toggles between one or the other, and that's it. I always read that "double amping" is bad, but that's exactly what one does when using the NFB-12's line out. :confused_face:
 
Jul 22, 2012 at 2:10 PM Post #2,068 of 2,278
Quote:
...
While I had the board in hands, I studied it to confirm what I said about the line out: it's connected to the output of the amplifier. As in, there is no difference between the RCA at the back and the TRS jack at the front. There's a relay that toggles between one or the other, and that's it. I always read that "double amping" is bad, but that's exactly what one does when using the NFB-12's line out.
confused_face.gif

Interesting information. Thanks!
Anyway, I'm not surprised neither reactive about that.
Many widely appreciated DACs use (lousy) opamps in the output stage to filter/amplify the signal...
At least in NFB-12 there are no caps on the path.
 
P.S.
IMHO and according to my ears "double amping" is bad if the amp stages are bad 
cool.gif

 
Jul 23, 2012 at 5:33 PM Post #2,069 of 2,278
Quote:
On the 12.1 looks like you can replace the coaxial or optical with a BNC connector.  Is that a digital or analog input?  I wonder if I could somehow feed an analog signal in there if I needed to?  I don't need the option often, but it's nice to have.
 


BNC is an improved COAX connection.  It's the same thing as a digital COAX except for that connector change with ensures the right impedance and has less jitter.  Already answered but no it is not an analog connection (but I don't know why you don't see BNC more often)
 
Jul 23, 2012 at 5:35 PM Post #2,070 of 2,278
Quote:
 
Any other thoughts or comparisons between the O2 and NFB 12.1?  I'm looking at both of these.  People say the NFB is more warm and the O2 more lean?  What about strength of the bass?


is that O2 plus the ODAC compared to the nfb12?  just asking since the nfb-12 includes a lot more and has more features.  Even if you combine the ODAC you're still missing the optical and coax connections the 12 has.
 

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