Just made my first CMOY, what next?

I made a CMOY amp with a JDS labs PCB.    Everything went smoothly, and I am pretty happy with the results.   I had no problem with assembly.  I was pretty hesitant to hook up something homemade to my DT900/600's, but after testing a good bit with some cheapo headphones, I took the plunge.  I designed it with a gain of 10, and am using it with two 9v batteries to help drive my 600ohm can's.  Comparing it to my Fiio E9, both can power my DT900/600's to well above comfortable listening levels, but the E9 sounds crisper on the highs, and is slightly better on the low end.    Overall, it's last 5% type of difference, and I have to be paying attention to notice the difference.  Really the most noticeable difference to me is in the highs on cymbal hits etc.

Looking forward, I'm wondering what my next project will be.  The main reason I made the CMOY was so I could have a transportable solution.   If I could run my E9 off batteries, it would be sufficient  for my needs right now.   I've been looking at the PIMETA v2 amp, but i wanted to ask what about the E9 makes it better sounding than the CMOY before diving into another amp.  Hopefully have an idea can help me tweaking/picking an amp design.

Is it the 3ch structure? 

Is it the buffer on the output?

Does the E9 class A bias it's opamps?

Would I really just be better off designing some sort of battery pack for my E9?

While I do have the parts for another CMOY, I don't have a balanced source or a balanced set of headphones, and don't intend on taking that step any time soon.   I was considering using my spare CMOY parts for PIMETA or similar unless one of my friends wanted a CMOY.

Maybe I should rephrase my question(s): (all in the context of a DT990/600)

How would adding a 3rd ch improve the sound? - I assume it would tighten the bass?

How would adding output buffers improve the sound? - I don't if it would impact much since I am not very current limited with 600 ohm headphones.

How would biasing into class A improve the sound?   - no idea.

I know what all of these things mean electrically, but I have no idea how it translates sonicly.   I can hear a difference between my CMOY and my E9, and I prefer the E9.  Supposedly the opamps in the CMOY are slight upgrade.to what I have in my E9.   What I like about the CMOY is it's portability.   Ideally, I'd make my own portable amp that sounds at least as good as my E9, but want to know what will make a difference in the design.

Quote:

Originally Posted by Mad Max 

Make a second cMoy and go balanced. 

 

You could try an upgrade PSU to improve your E9's performance.  Also, try OPA1642 or OPA2209 in place of the OPA2134 opamps in the E9.  Nice that they are socketed.

Care to comment on how those opamps might change the sound compared to the OPA2134?   I could easily buy buckets of opamps and test all day long, but having a "You might like this better because ___"  one liner for each could help me rule out most of them.   On that note, I might just build my 2nd CMOY to compare op-amps back to back.

Thanks.  That give me a starting point.  Based on what you said, I might give the OPA1642 a try as it seems more my cup of tea.