iBasso PB-2 Pelican fully balanced portable, DB-2 Dac . . HiFlight recommended op amps page 16. .
Mar 5, 2014 at 4:19 PM Post #1,066 of 1,604
I'd say it doesn't matter, given that I can't think of a single headphone that has three wires going to each transducer!

I'm sure that fellow is right so far as how to wire 3-pin XLR connectors between a balanced DAC and a fully balanced amp, for example, but eventually, you've got to get down to only two conductors per channel - for headphones or speakers. So, for most people, it's OK to call a four-wire headphone cable "balanced," while a 3-conductor headphone cable is called "single-ended" (or "unbalanced").

Try http://toxic-cables.co.uk - he won't get tripped up in semantics. :)



Mike


Thanks Mike.

I went to Frank at Toxic Cables and now have just received a beautiful looking balanced cable. No question that it is a work of Art.

Time to try it out to see if it sounds as good as it looks.
 
Mar 5, 2014 at 4:45 PM Post #1,067 of 1,604
Congratulations!  Yes, Frank does fine work.
 
beerchug.gif

 
Mar 23, 2014 at 5:08 PM Post #1,068 of 1,604
If I use the PB2 in the single ended mode, rather than balanced, can I get away with fitting only two single OPamps rather than four?

If so, into which sockets would I put them.

Thanks
 
Mar 24, 2014 at 4:27 AM Post #1,070 of 1,604
I always use in single mode with 2 buffer and 2 single TO-99 opa637

That surely can't be how the OPAMPS are installed right? My OPAMPS are installed as below

 
Mar 24, 2014 at 6:07 AM Post #1,071 of 1,604
Mar 24, 2014 at 6:38 AM Post #1,072 of 1,604
  That surely can't be how the OPAMPS are installed right? My OPAMPS are installed as below

 
You are using duals in L/R with singles as buffers.  But if you're using the TRS jack for single-ended cables, you could pull the first and third buffer op-amps (counting from left to right in your photo) and you wouldn't hear any difference.
 
Pitsel's photo is proof that using the PB2 single-ended gives us only half the power of going balanced with this design - but its still two-channel stereo, even with half as many op-amps.
 
Mar 24, 2014 at 7:02 AM Post #1,073 of 1,604
   
You are using duals in L/R with singles as buffers.  But if you're using the TRS jack for single-ended cables, you could pull the first and third buffer op-amps (counting from left to right in your photo) and you wouldn't hear any difference.
 
Pitsel's photo is proof that using the PB2 single-ended gives us only half the power of going balanced with this design - but its still two-channel stereo, even with half as many op-amps.

Thanks Mike!
 
Mar 24, 2014 at 8:04 PM Post #1,075 of 1,604
Yes Mike they are the HA5002 buffers. Those duals are LME49860 which is from the topkit in Aug last year
 
Mar 25, 2014 at 2:15 AM Post #1,076 of 1,604
Mar 25, 2014 at 6:53 AM Post #1,077 of 1,604
Joy!
 
It seems I'm hopelessly addicted to dummy buffers (at the expense of additional current) but, depending on your headphones, you might find you can better hear what the Muses01 brings to the table, at least for a little while, if you go "bufferless."  
 
This is analogous to something I once read at the forums of CoffeeGeek.com (paraphrasing):  If you really want to know what your non-dairy creamer is doing to the flavor of your coffee, just fill your mug with hot water - not coffee, then add the usual amount of creamer and drink up. Keep doing this until you find one that doesn't taste nasty. And by the way, good luck with that!
 
I have yet to find an op-amp that is as transparent as a dummy buffer. That's actually a gross understatement, given that a dummy buffer is nothing more than conductors, but the transparency is just as obvious to my ears as the understatement is to my eyes.  Even my best-sounding buffer (the HA5002) has a slight veil, best heard with something like the HD800 and a really noise-free DAC, like the Beresford Bushmaster MkII.
 
Lastly, just running the PB2 balanced out instead of single-ended gives me plenty of power (from two duals or four singles) for my LCD-2 or HD800.  With the LCD-2, I typically run the volume knob somewhere between 9 and 11 o'clock, but let me be the first to say that I'm probably forfeiting some dynamics and bass control by running dummy buffers, as the planar magnetics prefer power (volts * amps) that comes from amperage (via buffers) rather than from voltage (via the op-amps in L/R).  
 
And in truth, the LCD-2 is not ultra resolving, so I can tolerate the "veil" of the HA5002 when using the LCD-2, but I try to keep the lid closed on my PB2 - to protect my sanity from the incessant rolling of op-amps. I could easily get into pulling the HA5002 in and out, in and out, with the changing of headphones.  
 
It's all I can do to keep the lid closed.  As yet, I haven't resorted to putting Loctite Red on the case screws... 
 
t_lkr_red.png

 
Mike
(Currently running 2x Muses02 with dummy buffers, after several months using 4x LME49990 with dummy buffers).  
 
Mar 25, 2014 at 8:33 AM Post #1,078 of 1,604
Joy!

It seems I'm hopelessly addicted to dummy buffers (at the expense of additional current) but, depending on your headphones, you might find you can better hear what the Muses01 brings to the table, at least for a little while, if you go "bufferless."  

This is analogous to something I once read at the forums of CoffeeGeek.com (paraphrasing):  If you really want to know what your non-dairy creamer is doing to the flavor of your coffee, just fill your mug with hot water - not coffee, then add the usual amount of creamer and drink up. Keep doing this until you find one that doesn't taste nasty. And by the way, good luck with that!

I have yet to find an op-amp that is as transparent as a dummy buffer. That's actually a gross understatement, given that a dummy buffer is nothing more than conductors, but the transparency is just as obvious to my ears as the understatement is to my eyes.  Even my best-sounding buffer (the HA5002) has a slight veil, best heard with something like the HD800 and a really noise-free DAC, like the Beresford Bushmaster MkII.

Lastly, just running the PB2 balanced out instead of single-ended gives me plenty of power (from two duals or four singles) for my LCD-2 or HD800.  With the LCD-2, I typically run the volume knob somewhere between 9 and 11 o'clock, but let me be the first to say that I'm probably forfeiting some dynamics and bass control by running dummy buffers, as the planar magnetics prefer power (volts * amps) that comes from amperage (via buffers) rather than from voltage (via the op-amps in L/R).  

And in truth, the LCD-2 is not ultra resolving, so I can tolerate the "veil" of the HA5002 when using the LCD-2, but I try to keep the lid closed on my PB2 - to protect my sanity from the incessant rolling of op-amps. I could easily get into pulling the HA5002 in and out, in and out, with the changing of headphones.  

It's all I can do to keep the lid closed.  As yet, I haven't resorted to putting Loctite Red on the case screws... 


Mike
(Currently running 2x Muses02 with dummy buffers, after several months using 4x LME49990 with dummy buffers).  


Good idea. I will try replacing with dummy buffers.

Silly question - if you have no buffers at all what happens ???
 
Mar 25, 2014 at 3:04 PM Post #1,079 of 1,604
Hey Guys.  I just got the hiflightaudio kit yesterday and I really don't have a clue what I am doing.  I use my amp with my alpha dogs and hifiman headphones.  I also should have a DB2 coming in pretty soon.  Plan to run everything balanced.  
 
Anyways I see pictures of different things, I see hiflight pictures but they all look different.  Mine came with 4 chips with diodes on them. I put all those in the second row from the jumpers.  I then put 2 of the larger chips in near the jumpers.  I didn't like the way the first set seems to be breaking up in the highs.  I think it had white paint on them.  I then put in the set with red paint and it sounds much better.  
 
I can take a picture tonight but I would really like to just set this up and leave it alone.  Any advice would be much appreciated.  Thanks Nate
 
Mar 25, 2014 at 6:48 PM Post #1,080 of 1,604
Hey Guys.  I just got the hiflightaudio kit yesterday and I really don't have a clue what I am doing.  I use my amp with my alpha dogs and hifiman headphones.  I also should have a DB2 coming in pretty soon.  Plan to run everything balanced.  

Anyways I see pictures of different things, I see hiflight pictures but they all look different.  Mine came with 4 chips with diodes on them. I put all those in the second row from the jumpers.  I then put 2 of the larger chips in near the jumpers.  I didn't like the way the first set seems to be breaking up in the highs.  I think it had white paint on them.  I then put in the set with red paint and it sounds much better.  

I can take a picture tonight but I would really like to just set this up and leave it alone.  Any advice would be much appreciated.  Thanks Nate


Download the PB2 "manual" at the bottom of this page

http://ibasso.com/en/products/show.asp?ID=70

Don't the chips have markings on them to identify them? And then read this thread, there are some more details about the Topflight kits
 

Users who are viewing this thread

Back
Top