Time to update again. Fortunately the L R circuit is simple enough to understand so I swapped a few wires to reverse the both channels.

Before I plugged in the L700 I also checked the bias to make sure everything works in reverse order properly understand that a mistake could kill my headphone or maybe myself.

So the outcome is, the Left driver still having slightly weaker bass or impact. As I cranked up the volume knob to 3 o'Clock, there is left driver rattling noise again when heavy bass note hits during I put off the headphone...Exactly the same symptom before I swapped the channels. 

At this point I think I can conclude that my modded 007tii is fine but my L700 is the problematic culprit....Thanks again insanity for the suggested idea!

Edited June 14, 201610 yr by microCuts

No problem. At least you now know where your problem originates.

Updates for the bass impact imbalance.

Played with the L700 earpad before I wanted to send back to retailer.

The earpad is removable which is different from the previous lambda model. It is dead simple enough to remove and put it back with the snap mechanism.

I can see potential to mod this to enhance the bass by sealing the surrounding ring tighter. On top of the driver there is a loose webbing screen which I do not know what is that really for. Perhaps tighten it up in place can help to improve the bass as well? Who knows...

Okay, done with my curiosity and put everything back. Guess what, the bass imbalance is gone and everything works fine! Thus, I can only think of the previous guy who replaced my Left driver didn't put the earpad properly.

So that's all about my L700 & modded 007ii. Thanks Birgir and Kevin who brought up this fantastic mod which certainly improve Bass (until the point I'm able to tell bass imbalance), soundstage and also depth(the improvement in depth is greater than soundstage). Special thanks to Insanity as well who helped me to eliminate the amp problem quickly!

Edited June 19, 201610 yr by microCuts

your welcome. Glad you could solve the problem yourself. 

Hi guys, I need the 007t diagram for the 6s4a mod. Thank you.