[beyerdude]

For anyone interested I have a mint condition (but not working) E12DIY for sale on the for sale section - Would suit Australian buyers - I would say hard to repair as I stuffed up removing the stock capacitors (removed the circuit board traces) - don't assume its repairable unless you are a whizz with a magnifying glass/fiddly electronics.
 
Ideal for anyone who has stuffed up the case (it's silver unmarked) serial number 0900, it fits the muses opamp with no mod needed - battery like new (did not have too much use before it broke)....not sure if it's good form to post on here but I know people are on the lookout for cases after dremel accidents due to mods

 

[ClieOS]

 
Does this un-recommendation still hold? I ask because elsewhere on the forum some had suggested OPA2107 as a good opamp filter, and now I notice that Hifiman's flagship HM901s uses these specs: 
DAC chip: ES9018*2
Op-amp: OPA627*2， OPA2107*2

 
While from several reviewers in this thread OPA627 seems to make some kind of consensus as to delivering top-notch sound, OPA2107 seems more controversial...  Could you elaborate a bit more on OPA2107?

 
Implement is the key. Sometime a chip works out great on one circuit while sucks on another. In this case, OP2107 just doesn't bring anything to E12DIY. It is a little warm and mid centric sounding, lacking dynamic and feel boring overall.

 

[landroni]

 



 
Implement is the key. Sometime a chip works out great on one circuit while sucks on another. In this case, OP2107 just doesn't bring anything to E12DIY. It is a little warm and mid centric sounding, lacking dynamic and feel boring overall.

Thanks, good to know. Will stray away then. @Loquah also didn't find it particularly impressive.

PS Got confused about BUF634... Of course it's already included in stock E12DIY.
 

 

[landroni]

With the advent of HM901s and X7, with modular amp designs, we now have a better idea of what opamps manufacturers consider suited for a particular purpose. For the fun of it, I prepared this list of Hifiman amp cards and their specs, to give us a taste of the marketing-flavored descriptions of the individual opamp and buffer combinations.

 
Minibox Amplifier Card

1. Provides a Super Wide Frequency Range and Extremely Low Distortion
2. Opamp: OPA627 (x2)
3. Buffer: BUF634 (x4)

MINIBOX Gold Amp Card

1. Bringing High Fidelity Live Music to Your Ears is No Longer Just a Fantasy
2. Opamp: OPA637 (x2)
3. Buffer: BUF634 (x8)

IEM Amplifier Card

1. The HIFIMAN IEM Amp Card for In-Ear Monitor Users
2. Opamp: ???
3. Buffer: BUF634 (x2)

Balanced Amplifier Card

1. Great for Users Who Might Like to Experiment with Powerful Amp Module
2. Opamp: OPA627 (x4)
3. Buffer: BUF634 (x4)

 
Power II Amp Card

1. The Power II Amp Card
2. Opamp: ???
3. Buffer: ???

 
Musical Amplifier Card

1. Pure Musicality
2. Opamp: ???
3. Buffer: ???
4. Notes: Comes with the woolly "a classic differential amplifier as input and is supplemented with a NEC 2SD882 on both sides", whatever that means...

 
If anyone knows any of the missing chips above, please reply to this thread and I'll update the list. Now waiting with interest for the specs of the X7 modules... 


 

 

[ClieOS]

.... If anyone knows any of the missing chips above, please reply to this thread and I'll update the list. Now waiting with interest for the specs of the X7 modules... 
 

 
The only problem is that just listing down the combo of opamp and buffer totally ignores all the surrounding circuit of the amp. An amp is not just opamp and buffer chips, caps and resistors might be small, they are just as important.

 

[landroni]

 
 
The only problem is that just listing down the combo of opamp and buffer totally ignores all the surrounding circuit of the amp. An amp is not just opamp and buffer chips, caps and resistors might be small, they are just as important.

Absolutely, though it's a nice reference point. I also find it curious that for a flagship product Hifiman chose much the same components that many have been using all along with E12DIY: OPA627 and BUF634. Clearly OPA627 makes some sort of consensus, both with users and manufacturers, of being among the best of its breed.
 
I was only surprised to see OPA637 used as an upgrade to OPA627. Has anyone actually tried OPA637 with E12DIY? The only reference I could find in this thread is this post explaining that "OPA637 is not internally compensated for unity gain and is likely to be a lot less stable in the E12DIY"...

 

[ClieOS]

  I was only surprised to see OPA637 used as an upgrade to OPA627. Has anyone actually tried OPA637 with E12DIY? The only reference I could find in this thread is this post explaining that "OPA637 is not internally compensated for unity gain and is likely to be a lot less stable in the E12DIY"...

 
OPA637 isn't an upgrade over OPA627. It is just the faster version, so to speak - and in fact, too fast for audio use in most cases. The fact that TI lists both opamp in the same datasheet should also tell you that their performance ain't that far apart, but intended for different usage.

 

[landroni]

Before anything, I wanted to thank all for the kind feedback and assistance in this thread. Without it all, it would be impossible for a novice like me to squeeze every little inch of performance from this wonderful device.
 
This week I received my BrownDog adapters with soldered opamps/buffers. Interestingly they have a very tiny higher profile than the stock adapters, but fit perfectly the case nonetheless. As predicted by others, the AD8599/LME49600 was only very marginally better than the stock chips, whether AD8620 or OPA1611 (with same buffer). I could detect some improvement only if I was consciously looking for some improvement.
 
However plugging the LM4562/BUF634 proved a very different story. This is a very clear upgrade. It's as if for the first time ever I'm actually listening to the X3 DAC (or the Astrapi DAC) without interference, without a veil or coloration or anything... I never knew what people meant by "clean" or "transparent", but now it's clear it's a very welcome thing. 
 
 
Now I'm scratching my head how to trim 1mm off of the HA-5002 pins so as to make it fit the case...

 

[landroni]

 
 
BrownDog actually offers pre-mounted HA-5002 these days? That's great. Yep, those are exactly what you need. Be sure to insulate the top if they didn't do it, a piece of sticker or insulating tape will do. Also remember to trim 1mm or so off from each pins.

I'm not sure if I'm doing something terribly stupid, but after checking very carefully (several times, and as much as I physically could peek into the case) it seems like the BrownDog adapters that I received with pre-mounted HA-5002 fit just fine in the case, without bending the PCB or anything. It's true they're a bit taller, but after plugging them in there is just enough space for the insulating tape as well as a tiny little bit more. I closed my case and all seems to be working as expected...
 
Now trying out the NE5532/HA-5002 combo...

 

[ClieOS]

I'll say all the better if you can fit them in without and modification.

 

[landroni]

NE5532/HA-5002 is an awesome upgrade to the stock sound. It works mighty well for classical, too.


 

 

[xPakrikx]

knock off Muses ? :|
 

 
 

 

[ClieOS]

  knock off Muses ? :|
 

 
 

 
Yep, it does look like a fake.

 

[hellfire8888]

which combination of the opamp will give warm sound signature?

 

[landroni]

  which combination of the opamp will give warm sound signature?

One option is:
OPA627 + BUF634 for warmth and smoothness
 
See this post:
http://www.head-fi.org/t/674808/fiio-e12diy-limited-edition-version-diy-your-own-sound/2100#post_11948589