Last minute confusion related to amp purchase - help needed
May 10, 2014 at 8:15 AM Thread Starter Post #1 of 5

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After a lot of opinions, and more than 6 mails exchanged with Audio-GD's Mr. Kingwa, I was about to order an NFB-6 for use with my HD650 and RS1i cans.
 
While my source isn't balanced (DAC19DSP) Mr. Kingwa informed me that the NFB-6 could output true balanced as it can convert the signal. All I need do was re-cable my headphones.
 
However, he informed me that the DAC19 being single ended, would only output 1.2MA, as opposed to 1.2MA x 2 for a balanced DAC and for the HD650, I might find volume level to be low.
 
Would this be the case? Can anyone who has used the NFB-6 balanced with an HD650 but through an unbalanced source comment?
 
The solution would be to solder a couple of resistors inside the DAC19, boosting volume level to 2.4MA and maintaining the same volume as a balanced DAC. Since I have zero knowledge of soldering, I don't know what to do.
 
Should I:
 
1) Buy the NFB-6, try the volume level and see if its OK. Can anyone comment on the technical data mentioned above? Its mostly Greek to me!
2) Opt for the SA31SE instead and forget about balanced drive altogether
 
I do not want to remove my Ref 5 DAC off my loudspeaker setup, and I cannot afford to buy another balanced DAC this year.
 
May 10, 2014 at 3:42 PM Post #2 of 5
He's right in the respect that converting a balanced signal out of an unbalanced source will cut the output in half.  I would've thought it was voltage that was cut in half and not amperage, but that's a minor point in the context of what you're asking.
 
I can't tell you anything about the resistors, but it sounds fishy to me.  Amperage (MA as in MilliAmps) is also not synonymous with volume, but again - that's not the real point, I suppose.
 
The real issue is that "true" balanced is not possible if your source is not balanced.  It's only a "converted" balanced (see above).  You still get some advantages, but not nearly as much as if the entire component string was balanced, as in source to amp to headphones.
 
May 10, 2014 at 11:01 PM Post #3 of 5
  He's right in the respect that converting a balanced signal out of an unbalanced source will cut the output in half.  I would've thought it was voltage that was cut in half and not amperage, but that's a minor point in the context of what you're asking.
 
I can't tell you anything about the resistors, but it sounds fishy to me.  Amperage (MA as in MilliAmps) is also not synonymous with volume, but again - that's not the real point, I suppose.
 
The real issue is that "true" balanced is not possible if your source is not balanced.  It's only a "converted" balanced (see above).  You still get some advantages, but not nearly as much as if the entire component string was balanced, as in source to amp to headphones.


Hi tomb and thanks for replying. He also mentioned the volume for other "normal cans like the Denon D2000" would not really be an issue because it is 105dB, but for some other cans it might. I presume he means my HD650?
 
I am thinking of the NFB-6 cause its affordable, and balanced and I could of course try to upgrade my DAC at some point to balanced as well. The other option would be the SA31SE which is good old single ended, only thing being it doesn't have ACSS, only RCA. More confused than ever!
 
In response to your doubt about voltage being cut in half, I was referring to the ACSS connects, which are supposed to work in the current domain, which is why the current gets cut in half too. I suppose if I use RCA, that would get cut as well!
 
May 10, 2014 at 11:41 PM Post #4 of 5
 
  He's right in the respect that converting a balanced signal out of an unbalanced source will cut the output in half.  I would've thought it was voltage that was cut in half and not amperage, but that's a minor point in the context of what you're asking.
 
I can't tell you anything about the resistors, but it sounds fishy to me.  Amperage (MA as in MilliAmps) is also not synonymous with volume, but again - that's not the real point, I suppose.
 
The real issue is that "true" balanced is not possible if your source is not balanced.  It's only a "converted" balanced (see above).  You still get some advantages, but not nearly as much as if the entire component string was balanced, as in source to amp to headphones.


Hi tomb and thanks for replying. He also mentioned the volume for other "normal cans like the Denon D2000" would not really be an issue because it is 105dB, but for some other cans it might. I presume he means my HD650?
 
I am thinking of the NFB-6 cause its affordable, and balanced and I could of course try to upgrade my DAC at some point to balanced as well. The other option would be the SA31SE which is good old single ended, only thing being it doesn't have ACSS, only RCA. More confused than ever!
 
In response to your doubt about voltage being cut in half, I was referring to the ACSS connects, which are supposed to work in the current domain, which is why the current gets cut in half too. I suppose if I use RCA, that would get cut as well!


Hmm ... you learn something new everyday around here.
smily_headphones1.gif
  I had never heard of an ACSS connector.  I've had my hands on an Audio-GD nfb15.32, but it didn't have any of those connectors.
 
About the rest of your questions - why not try to compose a brief, but specific e-mail/message to Kingwa himself and get the rest of your answers?  He seems very helpful from what I've read. 
 
May 17, 2014 at 3:47 AM Post #5 of 5
Hi guys,
 
Purchased the NFB-6, from Audio-GD. Also purchased a couple of XLR 4 pin converting kits and an HD650 balanced cable.
 
Will definitely post A-B comparisons between my Micro Tube and this, as well as single-ended vs balanced.
 

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