Balanced v unbalanced input to Ayre preamps

Bob,
The surgery was successful, and I have not experienced any pain since.  The worst part was the 3-week taper off the opiates.

ciamara,
The Oppo 205 is claimed to be fully, i.e., dual differential, balanced.  I may use a passive switch for sharing a balanced input between the Sony HAP and the 205 until I get a KX-5 Twenty that has additional balanced inputs.

db

Good link to the Benchmark objective test. I suggest to try yourself with an inexpensive star-quad cable, or even to go to audiosensibility.com for a star-quad cable made with Ohno contiuous cast copper and Teflon insulation at a reasonable cost.

Can someone explain why handling a 600 ohm load is a critical factor for making cables used in balanced lines sonically a non-issue? It's not related to CMRR then, right?

These days 600 ohms is no longer the standard (although since transformers are still often used, its still around) although there is the expectation that the connection will have a low impedance input of 2000 ohms or less.

The reason for this is that if any noise is induced in the cable, it is usually a weak source (like a magnetic field) compared to the actual signal. So it does not have the same ability to drive the input load like the signal does. Its a simple means of 'swamping' noise out and has the added benefit of reducing the effect of capacitance in the cables.