I came across a Technics SH-GE70 and it works, but it seems like it needs a pretty hot signal to start seeing level on the spectrum analyzer. Like I plugged my Iphone in to it for testing purposes and if I'm half way on the volume I don't see nothing, then If I start going up from there I start seeing the meters move. I go all the way up on the volume and the meters are really moving. Just wondering if this is normal on this particular unit.