I should have added that whatever preamp I get will have to partner well with my amp, a Burmester 911 Mk3. The Burmester has a low input impedance, which affects choice of a preamp. I'm presently using an MBL 5011, and have thought of either a Burmester 011 or an MBL 6010D, but neither of them have balance controls. My room, 32 x 14, has a large, open arch to another room just a few feet from the left speaker. The right speaker has two walls, one behind it and another alongside, but the left speaker only has one wall, the one behind it. As you can imagine, this makes for an audible difference, particularly on some CDs. Hence my interest in balance control. I have ten accoustic resonators at various locations, and they help, though not enough on some source materials.