I listened to those B&Ws at my dealer's store. Then he swapped in a pair of Triangles. I went with the Triangles, and one of the reasons was their amazing imaging. You could find a pair of Comète ES used for your price.
Another make to look for would be Aurum Cantus.
Now for two cents' worth of system advice. It seems to me that your weak links at present are your receiver and your speakers. If you do change your speakers now, you will hear the receiver's limitations more clearly, so remember that when you plan your budget--you'll want to get your dream amp quite soon. Alternatively, keep saving and get the amp first and look for speakers second. A better amp will make your 601s a lot more pleasing.
I agree that an outboard DAC (and a good digital cable--budget $100 at least) would improve things, but I don't think this is a first priority. Sincerely, I would go for an amp first, then speakers, then I'd consider source gear.
If you want to improve the sound from your 1072, you can do it simply and economically by putting it on antivibration footers like Bright Star Isonodes or for a bit more money, Herbie's Tenderfeet. You could also get it a new power cord. The Acoustic Zen El Nino would be a good choice, and IIRC there's one available here right now.