My Valab(Late 2008 version) has been working fine with my Head-Direct EF-1.   I just got a Class-D amplifier (amp6-basic assembled) to drive a pair of Infinity P163.  It sounds great when I use the headphone jack of my notebook as source.  However, when I connect it to my Valab, I got a much...

Quote:   Now it works!  It happened to be  a bad connection of one TDA1543.  I loosen the heat sink of the TDA1543's and rock it a bit until both channel works.  It's now back to normal.  Thank you so much for trouble shooting the problem with me.  Now I've been messing around with the...

Quote: Just received the TDA1543's.  Replaced all 8 from the board.  Now the distortion is gone.  However, I only hear sound from the Right Channel.  The Right Channel sound fine though.  Do I just keep swapping the TDA1543 until I hear the left as well or do you think there is still...

Do you like your P163's?  I am in an exact same situation as yours.  If I don't hear any negative feedback from you, I will go ahead and accept their offer to get the P163's. 

Thank you so much for your suggestion.  Seems like it's not as bad as I thought.  I have ordered ten TDA1543 from Taiwan.  Will have to wait for the shipment. 

Need help trouble shooting my Valab.  Mine is a Late 2008 (Dec) version.  One of the very first generation.    I have been using it with the Turtle Beach Audio Advance Micro optical output without any problem.  I usually run my computer under Linux.  I need to switch to Win7 to get something...