Having two Z1 I´m surprised to listen that one sounds more brilliant.
Unluckily the inferior one has the voice expansion. I´d totally like to
install it into the superior. The only thing I could do were to open
both and watch how DSPBZ1 is installed, but before exchange I really
have to know if there are instructions on the software side (perhaps
initialisations or service routines from the service manual
before/after??) At least I got a serv. manual but without advice I
beware of touching anything. So I were glad if anyone could answer this
question.

regards
Gerry