Question

I want to buy Presonus Studio 68 + Eris E5 combo.

I`ve cheched the descriptions about Studio 68 and found that other devices of Studio Series has EIN -128 dbu but only Studio 68 has -130 dbu. It seems like this is about mic preapm self noise or smth and Studio 68 is even better in this case. But how can it be possible - i believe that all Studio Series have the same XMAX Preamps? (except Studio 26 with L-XMAX)

Answer 1

Any electrical component has +|- tolerances.  Also, every device has its own designed circuit.  Each product in the Studio USB Series has it's own design and requirements.  They will not be exactly alike.  There are also rounding and averages to consider when measuring specs.  A 2 decibel differential seems negligible to me.  Of course it may depend on what you are measuring and what your intended use is.  Also of course, every setup and environment has to be "dialed" in anyway.