Have u had a chance to listen to the Beyerdynamic T90? I am quiet impressed.

Thank you.   I have taken the advice from Ron (HiFlight) and decided to go with the set up that he recommended and which he kindly agreed to provide to me.   He appears to be very knowledgeable and gave me a lot of information. Very nice guy. I will update once I have the set up that he...

made a mistake:   the LME49990 has either the ending "MA" or "NOPB"   Which one do I need to get for the P4? What is the difference. 

Also   I found the LME4990 online in Australia. However is full title is "LME49990 MA" or "LME49990 NOB" - Is this what I need for the P4? What is the difference between "MA" and "NOB". Does it matter?   I also found the ISL5002 again described as ISL5002 21bz   -   Is this correct?

I love sound and I am, as you also appear to be, with finding the best sound within my budget.   I habe recently upgraded my headphones from "Grado 325is" to the "Beyerdynamic T90" which I am very happy with.    Today, I purchased the iBasso P4 portable amp which you have discussed in...