Hi PS Audio team and forumers. I have a dilemma with my M700.
The M700 monos is driving a pair of ATC SCM11 and preamp is Primaluna Prologue. Straight out from the box, they sounded flat and lack air. After 2 weeks of use it has slowly become more open sounding but also picks up nasty upper-midrange hardness and forwardness especially with female vocals. The high frequency is smooth though. When I swap back to a Pass Aleph 3, the upper midrange hardness was gone.
I’ve had the M700 since mid September. Playing on average 1-2hrs a day. From Stereophile and Positive-Feedback reviews, the M700 has a smooth midrange. Can my midrange issue be due to lack of running-in? If so, how long do I need to get to that smooth midrange tone? Can I just leave the power amp on without feeding music to run-in the amp?