[Lohb]

Looking good Mike regarding the OPAMP technical stuff....
 
I just picked up a better quality than generic printer cable, and after half-an-hour, worked the 4th pin completely out with a razor and tweezers as per your data-only USB plug method for split USB cables.I used tape for the 4th pin on another previous cable, but it never lasts when you remove the USB cable from the port daily.

 
http://www.head-fi.org/t/647693/sonic-satori-hrt-levels-the-field-with-the-microstreamer/1155#post_12640560
 
Will have my Hirose male plug fitted on an 8-line Sterling Silver IEM cable by tomorrow locally....
But I know I cannot AB exactly, even taking account for volume. I find the middle/high gain adds more bite/attack/dynamics to the presentation for some reason, and I think it is not purely volume but the impedance or something is working with the end IEM/headphones to present it slightly differently....I think that came up in the H10 thread as well.
 
Have yet to see if the base of the case can screw off, if yes, may anodize it or power-coat upper and lower case and leave the rear and front as it is.
 
Just pulled the AD797...found them too dry in the mids/treble...now using OPA604 + dummy buffers which has a richer tone and fuller sound than AD797... until I can get my hands on DIP8 units to raise 2 of the Bursons up and keep 2 low.

 

[Makiah S]

has any one yet to well rebuild a PB2? Like from stratch, I wonder what it would cost to manufactor a clone with a larger space for opAmps. Granted that might bump into some copy Right infiringments, but I keep getting the sense that we all really need just more space in this Amp to work, an there has to be a better solution than what were currently doing imo 
 
with regards to the sound of the different gain settings, I've also enjoyed running low gain on all my dynamic headphones, on my HE 4 Medium gain sounds the best imo, still I'm enjoying the LME 49990s as I always have, my only issue has been and will always be there's a touch of noise when I adjust the volume, I clean the amp out from time to time and re seat the amps, and it kinda helps, but I really just need to get new opAmps and with 8pin DIP adapters, 
 
either way still enjoying this little amp an awful lot ^^ I'm excited as my Hm901 and PB2 combo has been getting more head time recently 

 

[Lohb]

I notice a pop on or off, so no earphones in the 3.5" when switching on or off...I roll the volume to zero before removing inserting IEMs.
 
A mute relay would have helped unless that is just the used amp's style  I picked up.

 

[Lohb]

...my only issue has been and will always be there's a touch of noise when I adjust the volume, I clean the amp out from time to time and re seat the amps, and it kinda helps, but I really just need to get new opAmps and with 8pin DIP adapters,   
 

Roll the volume pot from zero to 100% many times while switched off. That may loosen any dirt/dust and fix the issue.

 

[zilch0md]

  Looking good Mike regarding the OPAMP technical stuff....
 
I just picked up a better quality than generic printer cable, and after half-an-hour, worked the 4th pin completely out with a razor and tweezers as per your data-only USB plug method for split USB cables.I used tape for the 4th pin on another previous cable, but it never lasts when you remove the USB cable from the port daily.

 
http://www.head-fi.org/t/647693/sonic-satori-hrt-levels-the-field-with-the-microstreamer/1155#post_12640560
 
Will have my Hirose male plug fitted on an 8-line Sterling Silver IEM cable by tomorrow locally....
But I know I cannot AB exactly, even taking account for volume. I find the middle/high gain adds more bite/attack/dynamics to the presentation for some reason, and I think it is not purely volume but the impedance or something is working with the end IEM/headphones to present it slightly differently....I think that came up in the H10 thread as well.
 
Have yet to see if the base of the case can screw off, if yes, may anodize it or power-coat upper and lower case and leave the rear and front as it is.
 
Just pulled the AD797...found them too dry in the mids/treble...now using OPA604 + dummy buffers which has a richer tone and fuller sound than AD797... until I can get my hands on DIP8 units to raise 2 of the Bursons up and keep 2 low.

 
Hey, good job on getting rid of the 4th pin.  Replacing the tape is a nuisance, for sure.
 
In Europe, there are several people who really like this product for accomplishing the same thing - the SBooster VBus2 Isolator:
 
https://www.sbooster.com/sbooster-tweaks/sbooster-vbus-isolator?language=en
 
Unfortunately, they refuse to sell directly to wanna-be customers in the States, but you can ask them for the contact info of a "dealer" here in the States who will do business with you by email - no website, not even a Facebook page, quotes by email and he uses his girlfriend's PayPal address to take payments.  Very flaky - no thanks.  (Just my opinion, having never actually done business with him, stopping short at receiving his unprofessional, hastily thrown together emails.) 
 
SBooster has some very highly regarded LPS, also, but just try and buy one.
 
---
 
It's sounds as if you're going to have a nice cable when it's done.  Enjoy!

 

[zilch0md]

@Lohb   And, by the way, you should write iBasso and ask them if they have any spare part cases for the PB2 lying about.  For real.  They sent me a top and bottom - no end plates, for only $20.00 U.S., shipping included.  That was about eighteen months ago, so I don't know what they still have in the way of inventory, but it's worth asking, and that way, you can try anodizing without risking the original parts.  

 

[Lohb]

  @Lohb   And, by the way, you should write iBasso and ask them if they have any spare part cases for the PB2 lying about.  For real.  They sent me a top and bottom - no end plates, for only $20.00 U.S., shipping included.  That was about eighteen months ago, so I don't know what they still have in the way of inventory, but it's worth asking, and that way, you can try anodizing without risking the original parts.  

Nice. I still want to pull the original battery and load a nice juicy cap in that space....hahaha.
But I won't, after your previous post on how it can affect things adversely.

 

[Makiah S]

 
Roll the volume pot from zero to 100% many times while switched off. That may loosen any dirt/dust and fix the issue.

thank you, I'll have to do that right away 
 

  @Lohb   And, by the way, you should write iBasso and ask them if they have any spare part cases for the PB2 lying about.  For real.  They sent me a top and bottom - no end plates, for only $20.00 U.S., shipping included.  That was about eighteen months ago, so I don't know what they still have in the way of inventory, but it's worth asking, and that way, you can try anodizing without risking the original parts.  

mmhmm I may do that as well, just to have the parts for my self too 

 

[privilege15]

  Thanks Mike, as thorough as ever !
I'm going to go through the Pelican case dimensions next for it as sometimes I have water bottles in my sling/torrential rainy season downpours etc.
Will add any information to the PB2 database. Currently using this for DAC and IEMs.

 
Pelican 1050 for PB2 with an Energizer/XPAL external battery combo by the looks of it....

 
 
It’s been quite some time since I retired from searching for the right sound that would soothe my ears after spending thousands of dollars on various buys and tries. Since I found the right one I rarely pay visit to head-fi, only to scan through interesting updates on the market. Non spotted though)
 
Although I don’t think I shared one of pictures on how I actually store my setup which might be useful to someone. I bought this waterproof pelican case last year for this very purpose. It’s a 1075 pelican case with foam inside:
 

 
I put the relevant sticker on it which was lying around:
 

 
And that's how everything is organized inside:
 

 
I do really think that the PB2 is the heart of the whole system. The DAPs are replaceable, there's plenty and one on the market but PB2 is the only and almost extinct powerful beast. It will never get old and most of the time (depending on what internals you have...obviously there must be something better than the stock ones) it will beat all those fancy new super duper portable amps and a good deal of the desktop headphone amps.
 
If you have one, never lose it.

 

[Lohb]

Yeah, it is a superb amp, and I like that case you have but for me I think the 1060 will do it for my needs...another energizer LPS user I see

 

[Lohb]

@stillevil what chips did you finally settle on ?
 
I'm running the OPA604 OPAMPs + dummy buffers which I found the best of the stocks chips for my own taste and IEMs. I read the 604 comes alive the more voltage you feed it up to a point.
 
Anyone looking at the new Burson V5i chips, get dual chips for PB2, not singles like me....doh !
I just could not estimate their size from the website photos.

 

[privilege15]

  @stillevil what chips did you finally settle on ?
 

 
I'm running with MUSES01 opamps and LT1028ACN8 buffers with 8-pin DIP heatsinks because the buffers become pretty hot.
 
I read on some other DIY forum for hi-fi/hi-end electronics that LT1028ACN8 go really well with MUSES01. That's how I tried this combination which eventually appeared to be the final one.
 
I thought of trying Bursons or Sparkos but then I asked myself "What's the point?" as I already have one of the best sounds for my taste by comparing it to many of the setups I tested, be it my own or someone else's or demo samples in stores.
 
I tried running MUSES01 with dummy buffers at first. The sound was NOT as good as with LME49990 opamps+dummy buffers which I previously used so I rolled back and put the MUSES01 aside in the drawer. At the same time I ordered LT1028ACN8. When the set of new buffers arrived I inserted MUSES01 and LT1028ACN8 and that's when I had my jaw dropped to the ground. When I found it, I already knew this is it, that's exactly what I needed.
 
Don't get me wrong LME49990 is a good opamp but I did not feel that I was completely satisfied with it. Something was missing/weird/strange but I could not say what exactly so I kept searching. Eventually my brain got in total harmony as soon it heard the combination of MUSES01 and LT1028ACN8 and of course balanced Beyerdynamic DT-150 headphones (250Ohm) plugged into PB2 with handcrafted with my own hands custom cable, the search was over. After this I sold most of my other audio stuff as considered to my tastes to be inferior to my current one.
 
DISCLAIMER: everything said is strictly regarding my taste

 

[Lohb]

   
I'm running with MUSES01 opamps and LT1028ACN8 buffers with 8-pin DIP heatsinks because the buffers become pretty hot.
 

What is the sound signature like on that combo ?
2 dual Muse ?
I see multiple product number codes online.

 

[privilege15]

All MUSES01 are dual...I think. At least I never heard about the single ones. The codes on the chip itself might be different. It's better to order from Japan. There are many fakes around.
 
As for the sound signature it's completely neutral and crystally transparent for me with on the spot amount of bass and on the spot middle and highs. It's almost like if you imagine the flat frequency curve in 2D as a square metal plate through which you can't see but then imagine that this plate turns into crystal glass reveling every hidden nook behind it. I felt like there was no more fog, not even a haze to hide anything from me while being 1 on 1 with the composition.
 
That's approximately how sound signature looks like

 

[Lohb]

   It's almost like if you imagine the flat frequency curve in 2D as a square metal plate through which you can't see but then imagine that this plate turns into crystal glass reveling every hidden nook behind it. I felt like there was no more fog, not even a haze to hide anything from me while being 1 on 1 with the composition.
 
That's approximately how sound signature looks like

Haha, I say that kind of stuff to my friends and they are like "W.H.A.T. ?"