iBasso PB-2 Pelican fully balanced portable, DB-2 Dac . . HiFlight recommended op amps page 16. .

Jan 14, 2014 at 5:02 AM Post #991 of 1,606
hmmm i might have to give that a go. i have tried i would say a decent ammount of  opamps and buffers....and came to the conclusion that the lme49990 is bar none IMO, and the ha5002 the best buffer offering great current gain.....with the gain setting on high and that combo, you have a seriously powerful amp.


Im getting one of these new in the next week or so. Ill most likly b usung dummy buffers as i have a bwlnced D2k that doesnt nrrd much powet

which dummy buffers r most transparent n where do i get a quad of lme49990s ... and do i need n adapter :3
 
Jan 14, 2014 at 10:44 AM Post #992 of 1,606
Im getting one of these new in the next week or so. Ill most likly b usung dummy buffers as i have a bwlnced D2k that doesnt nrrd much powet

which dummy buffers r most transparent n where do i get a quad of lme49990s ... and do i need n adapter :3

A dummy buffer is just a bypass to the socket so all you have is a wire going from one point to another. There are no chip in place. 
 
Jan 14, 2014 at 10:46 AM Post #993 of 1,606
Im getting one of these new in the next week or so. Ill most likly b usung dummy buffers as i have a bwlnced D2k that doesnt nrrd much powet

which dummy buffers r most transparent n where do i get a quad of lme49990s ... and do i need n adapter :3

 
You can buy two (2) of these (one for each channel) from the ebay seller named "frugalphile" - I've done business with him several times and have always been very impressed by his soldering skills and his business practice.
 
http://www.ebay.com/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190999739495?pt=US_Amplifier_Parts_Components&hash=item2c7878bc67
 
They include the DIP8 adapters (again, nicely soldered.) 
 
IF you would prefer a quad of singles (instead of two duals), you can order two (2) of these from the same seller, instead:
 
http://www.ebay.com/itm/2pcs-LME49990-DIP8-ADAPTERS-/190897296160?pt=US_Amplifier_Parts_Components&hash=item2c725d9320
 
Mike
 
Jan 14, 2014 at 10:51 AM Post #994 of 1,606
  A dummy buffer is just a bypass to the socket so all you have is a wire going from one point to another. There are no chip in place. 

 
 
   
You can buy two (2) of these (one for each channel) from the ebay seller named "frugalphile" - I've done business with him several times and have always been very impressed by his soldering skills and his business practice.
 
http://www.ebay.com/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190999739495?pt=US_Amplifier_Parts_Components&hash=item2c7878bc67
 
They include the DIP8 adapters (again, nicely soldered.) 
 
IF you would prefer a quad of singles (instead of two duals), you can order two (2) of these from the same seller, instead:
 
http://www.ebay.com/itm/2pcs-LME49990-DIP8-ADAPTERS-/190897296160?pt=US_Amplifier_Parts_Components&hash=item2c725d9320
 
Mike

so for a low gian balanced set up, it would be best to get maybe a quad of those LME 49990 adapters and install the dummy buffers, and ofc have the gain set to low 
 
what are the variable gain settings, I'd like to keep it at... at most 3 for balanced out, My w1000x is sensitive :x
 
hoping in the next week to maybe find a used Pb2, and not have to buy new, but I can afford new if need be plus I've got a pb1 so I have the adapter, already so what $325 + $35 for the 4 opamps + shipping would be around $400 or so for a new amp, not bad $100 less than an RSA F-35 and  I don't need another adapter 
 
Jan 14, 2014 at 10:55 AM Post #995 of 1,606
My opinion:  
 
Always select the lowest gain that allows sufficient volume with your headphones - even if you have to turn the knob well past 12 o'clock.
 
This does two things for you:  It gives you the lowest noise floor during silent portions of your music -and- it gives you more finesse to fine tune the volume than you would have at a higher gain setting, where the volume control has to stay closer to the zero position.
 
The iBasso PB2 has four sets of jumpers, each with three possible postions - Hi / Med / Low gain.  See the manual for a diagram of how to set the jumpers (on Low, to start with).  Again, if that gives you sufficient volume, you're done - leave it on Low gain.
 
Mike
 
Jan 14, 2014 at 11:09 AM Post #996 of 1,606
   
You can buy two (2) of these (one for each channel) from the ebay seller named "frugalphile" - I've done business with him several times and have always been very impressed by his soldering skills and his business practice.
 
http://www.ebay.com/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190999739495?pt=US_Amplifier_Parts_Components&hash=item2c7878bc67
 
They include the DIP8 adapters (again, nicely soldered.) 
 
IF you would prefer a quad of singles (instead of two duals), you can order two (2) of these from the same seller, instead:
 
http://www.ebay.com/itm/2pcs-LME49990-DIP8-ADAPTERS-/190897296160?pt=US_Amplifier_Parts_Components&hash=item2c725d9320
 
Mike

I'm going to quote it as often as I can so I don't forget it [or email to my self herp derp] 
  My opinion:  
 
Always select the lowest gain that allows sufficient volume with your headphones - even if you have to turn the knob well past 12 o'clock.
 
This does two things for you:  It gives you the lowest noise floor during silent portions of your music -and- it gives you more finesse to fine tune the volume than you would have at a higher gain setting, where the volume control has to stay closer to the zero position.
 
The iBasso PB2 has four sets of jumpers, each with three possible postions - Hi / Med / Low gain.  See the manual for a diagram of how to set the jumpers (on Low, to start with).  Again, if that gives you sufficient volume, you're done - leave it on Low gain.
 
Mike

Yea I want LOW Gain, my pb1 is set to high gain ... permantly due to the smashed Gain Pins on the bottom [my fault / crappy build quality] so... well I paid $60 for it and it's my HIGH GAIN OH YEA amp, it works nicely with the DT 880 600 ohm, noise is low and I do NOT like loud volume but some ppl do, had a guy MAX out my pb1 yesterday [in balanced out] he was... happy
 
non the less I want LOW LOW LOW gain for my Dynamics, the 32 ohms ones. I've got my wanted add posted, so let's see what happens
 
thank you for the link to the opAmps as well. 
 
Jan 14, 2014 at 5:04 PM Post #997 of 1,606
Im getting one of these new in the next week or so. Ill most likly b usung dummy buffers as i have a bwlnced D2k that doesnt nrrd much powet

which dummy buffers r most transparent n where do i get a quad of lme49990s ... and do i need n adapter :3

Check out HIFLIGHT on here he makes great kits for the pb2.
 
Jan 14, 2014 at 5:22 PM Post #998 of 1,606
I don't think Ron (HiFlight) offers LME4990s currently, or I would have mentioned him.  Ron is certainly a great guy to deal with and has bent over backwards for me a couple of times, helping me with problems.  
 
In fact, Mshenay might want to send Ron a PM with photos of his damaged gain jumpers, to see if Ron might be willing to give a quote for fixing them.  He's in Florida - not China.  :-)
 
Mike
 
Jan 14, 2014 at 5:30 PM Post #999 of 1,606
  I don't think Ron (HiFlight) offers LME4990s currently, or I would have mentioned him.  Ron is certainly a great guy to deal with and has bent over backwards for me a couple of times, helping me with problems.  
 
In fact, Mshenay might want to send Ron a PM with photos of his damaged gain jumpers, to see if Ron might be willing to give a quote for fixing them.  He's in Florida - not China.  :-)
 
Mike

Nah It's time to upgrade my amp truth be told :3. I wanted the pb2 but I settled for the Pb1, so I'd like to try the LME 49990 Pb2 as my upgrade for this Spring 
 
but a good idea thank ya :D 
 
Jan 14, 2014 at 6:18 PM Post #1,000 of 1,606
I asked somebody whether he could make a balanced cable for me to my Sennheiser 600HD and he made the following comments.

The trouble is this is not a true balance system as Sennheiser has only 2 terminal per channel - ground and positive.

A balnced cable needs - Ground - Positive - Negative - wired the same at both ends whhich is why it is called balanced.

http://www.scotaudio.com/wiring.htm

The iBasso link shows a connector that is XLR (ground and positive for each channel) which is essntially the same as the one I made for you except I used a mini jack connector rather than XLR.

I can make one of these up for you but do be aware it is not really a balanced cable.

Does this matter?
 
Jan 14, 2014 at 10:57 PM Post #1,001 of 1,606
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
 
Jan 15, 2014 at 1:37 PM Post #1,002 of 1,606
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

Ugh yea dude Frank know's his stuff also... is that an LCD being driven by the PB2 :O... me gusta
 
Honestly some one needs to mod a pb2 to have adjustable gain on the Fly like the PB1 did, it's a shame you have to open it to adjust gain :/ 
 
still I also want a white one my self :D 
 
Jan 15, 2014 at 1:53 PM Post #1,003 of 1,606
i use the pb2 with +10 gain and have pitch black imaging and silent floor...but it could be the use of balanced mode and using the db2 boomslang, i use a decent ammount of iems on this setup.
 
Jan 15, 2014 at 2:20 PM Post #1,004 of 1,606
I think the PB2 and DB2 are one of the most overlooked combos or even individual pieces of electronics in the high end portable market. People just don't realize until they use them how good they are and frankly, at a bargain price for what you are getting. 
 
Jan 15, 2014 at 2:20 PM Post #1,005 of 1,606
  i use the pb2 with +10 gain and have pitch black imaging and silent floor...but it could be the use of balanced mode and using the db2 boomslang, i use a decent ammount of iems on this setup.

Nice, the hm801 may not be as quiet as the DB2, how ever my pb1 isn't noisy, it just lacks any Volume control. There's way to much gain to be able to adjust the volume suitably, and I have a lot of classical and EDM so... :/ 
 

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