[Loquah]

  Do you still have an audible hiss with the DIY version? The E12 does which is slightly annoying. I'm using mine with the Sony NWZ-ZX1 and JH13 Pros.

 
Zero hiss unless the DIY is on high gain mode
 

For me I have settled on the Muse 02 op amp, LM4900 buffer in high bandwidth mode with 220 ohm resistors only raising the band width ever so slightly over the low bandwidth mode and Black Gates Nx HiQ 47uF 6.3V capacitors running my Sennheiser HD650's, it took over 300 hrs to burn in the capacitors but I'm done, this combo is the one for me. In the photo I have the the HA 5002's in which is my second favorite buffer.

 
What is the benefit of changing the bandwidth?

 

[vilhelm44]

   
Zero hiss unless the DIY is on high gain mode
 
 
What is the benefit of changing the bandwidth?

 
Thanks. I ended up ordering the E12A.

 

[nmatheis]

You'll enjoy the E12A!

 

[LeeU]

It raises the quiesent current slightly and raises the band width from 110 mghz to 130 mghz,110 is way more than needed I know but the buffer just sounds better with a slightly higher quiesent current in my opinion

 

[K.T.]

It raises the quiesent current slightly and raises the band width from 110 mghz to 130 mghz,110 is way more than needed I know but the buffer just sounds better with a slightly higher quiesent current in my opinion

Do you notice an effect on battery life? As in shorter life because of the increased current?

 

[LeeU]

Not much, I did not go all out, just raised it a little, there has been a lot discued on other forums about high bandwidth on the buf634 and the 9600 about overall sound clarity improvements by going high bandwidth, I agree, it is important to at least go with a 220 ohm resistor as any thing less hurts the sound.

 

[K.T.]

Sounds good. But how about when you change to something like HA-5002 or another buffer?

Will the higher biasing still work and give improved sound? Or is the mod just specific to the BUF634 and 9600?

I might be interested in doing this mod.

 

[LeeU]

The resistor is soldered on each buffer,so X 2 for the 634 X 2 for 9600

 

[LeeU]

I used Vishay audio quality 1/10 watt resistors

 

[K.T.]

The resistor is soldered on each buffer,so X 2 for the 634 X 2 for 9600

OK, that makes a lot of sense. Biasing resistors are specific to the buffer and soldered directly on to them.

Can you give more info about the resistors?

Would that be a surface mount package, or through hole resistors? There's not a lot of room in the case, but those really low wattage through hole resistors can be quite tiny.

 

[Loquah]

I've been playing around today and the OPA627 has made a huge comeback in my personal op amp preferences - possibly due to a different set of IEMs this time.
 
What's more interesting to me though is how much trouble I'm having deciding if I prefer BUF634 or LME49600. LME49600 apparently measures better, but the sound from BUF634 seems more spacious and organic to my ears. What is everyone else finding?

 

[beyerdude]

  I've been playing around today and the OPA627 has made a huge comeback in my personal op amp preferences - possibly due to a different set of IEMs this time.
 
What's more interesting to me though is how much trouble I'm having deciding if I prefer BUF634 or LME49600. LME49600 apparently measures better, but the sound from BUF634 seems more spacious and organic to my ears. What is everyone else finding?

I found the same with my IEMS (Havi B Pro) - the Buf634 with the default AD797 and then the OPA627 worked best but with 300ohm headphones I find the LME49600 a better match - also your point on the OPA627 is similar to my findings - last week I swapped the Muses02 to the OPA627 for the first really long (week long) audition and found the sound immensely enjoyable

 

[Loquah]

The OPA627 is a sneaky good op-amp. It's newer brother, OPA827, is more striking and engaging on first listen, but OPA627 has this endless sense of space and texture to instruments that I can't find anywhere else except the LM49990 which comes close, but falls a bit short on overall realism due to the slightly "plastic" sheen it creates in the sound.
 
After much swapping today to find the ultimate combo for my new Noble K10s, I am down to the HA-5002 or BUF634 with either the OPA627 or the NJM5532...

 

[beyerdude]

  The OPA627 is a sneaky good op-amp. It's newer brother, OPA827, is more striking and engaging on first listen, but OPA627 has this endless sense of space and texture to instruments that I can't find anywhere else except the LM49990 which comes close, but falls a bit short on overall realism due to the slightly "plastic" sheen it creates in the sound.
 
After much swapping today to find the ultimate combo for my new Noble K10s, I am down to the HA-5002 or BUF634 with either the OPA627 or the NJM5532...

For some bizarre reason I never gave the opa627 a fair chance, which considering it's about the most expensive op amp around is ironic - perhaps due to my first test of one being paired it with a Neco amp years ago and Beyer DT880 600ohm and it sounded plain DULL - I have since realised that it was more to do with the amps inability to drive 600ohm headphones well rather than the OPA627 - at the time I assumed that since it had enough volume it must be able to drive 600ohm well which I have since discovered to be one of the more common errors with these headphones!

 

[Loquah]

Yeah - I never really noticed the full magic of the 627 until today with the K10s. I am now trying the same combo with the SE846 and while it sounds good, it's just not as amazing as with the K10s - it's like the OPA627 is a high performance sports car that needs just the right roads to really appreciate it (or in this case just the right 'phones) - I think one of the keys is treble extension and resolution where the brighter, but highly refined K10s can show off how smooth the 627 is without getting thick like the 846s can