Mhu,
I own the Berning ZH270. I use the normal setting and run the volume wide open. This effectively eliminates both volue controls being in circuit. I find that the music has much more dynamics to it this way. Yes it does limit how far you can turn up the volume on the preamp and you may get a little more background hiss, but I find this to be a small tradeoff for the increase in dynamics.
I own the Berning ZH270. I use the normal setting and run the volume wide open. This effectively eliminates both volue controls being in circuit. I find that the music has much more dynamics to it this way. Yes it does limit how far you can turn up the volume on the preamp and you may get a little more background hiss, but I find this to be a small tradeoff for the increase in dynamics.