[ProtegeManiac]

 
I want a warm sounding amp, E12a is really good , but just not my cup of tea as its really bright, improves detail in the upper region, makes male vocals very edgy and prone to sibilant.
 
I would want an amp to drive my he400, with reducing some treble, while boosting sub bass. More warm sounding amp.
 
Of course the clipping should be eliminated.

 

  I have an E12 not a and it drives the 400's just fine for me I don't know about the a model but if I drive the E12 to clipping I wouldn't be hearing much after that. 

 
He has the E12a, the low gain IEM version.

 

[buke9]

   
 
He has the E12a, the low gain IEM version.

Now I understand the clipping as the E12 not turned to 16db just won't push them very well.