My McIntosh C42 sounds sublime and has a wonderful balance control.
I use a Jeff Rowland Capri SS pre. It has balance control on its remote, home theatre bypass, differentially balanced and single ended input/outputs, optional phono stage. I prefer it over my own ARC Ref 3. I have posted information on it on several threads, including:
The device sounds reasonably good out of the box, then keeps improving for perhaps 1000 hours of music making, until it becomes truly outstanding.
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.
Kusina, Your room is very similar to mine in layout (though different dimensions). The large opening can be very well tamed by toeing in your speakers. You are probably a bit heavy on the walled side vs. the open side, due to the reflections. Toeing in your speakers will help to alleviate some of the added emphasis to this side of the room. My experience is that the balance control will help even out the sound, but my experience is that it has a negative impact in terms of sound staging. If you are going to address this with a preamp with balance controls, the Capri would be a good unit as would their top of the line model (which may be better budgeted to your system). The suggestion of a TACT preamp would also be interesting, while I have not personally had such a preamp in my system, they are supposed to be capable of addressing such issues very well. The overall sound and all that digital manipulation is what concerned me with the Tact units - but others report very favorably about their performance.
For what it is worth, my walled side (which is all windows) I address the problem with heavy curtains that I close for critical listening. This has balanced it out nicely and I don't find my balance being out of whack, so to speak. I also have my speakers toed in and sit closer than you to reduce the room interaction.
Ckoffend, Thanks for an account of your experiences and some suggestions. My speakers are toed in a bit, and I'm disinclined to move them. Their large spikes have penetrated the Chinese rug that they are on. My wife has either not noticed or has chosen not to say anything, and I don't want to call attention to the situation. (I've talked to a local rug dealer, and he claims he can repair the damage, but I'll wait.) Anyway, I sit about 18 feet from the speakers, and while my wife is willing to rearrange the furniture, we haven't been able to figure out how. So I'm thinking of electronic fixes. Another possibility might be a wooden screen that I could put in place alongside the left speaker for serious listening. I'll experiment, though a balance control might prove to be the most elegant solution.