combining different cables

I believe that using only the same brand and model of cables is a very good starting point. After that, one may find that different cables may work best between different components and as a complete system. I try to get manufactures opinions (not always easy to extract, even thought it would be in their best interest; business diplomacy can be a tough obstacle to overcome) as to what works best with their gear, and see if there is any consensus amongst them to use as a starting point. For example the manufacturer of my pre and power amp used the immedeate precursor of my speakers as one of their references during the design, the manufacturer of my speakers used the same power amp as one of their references during the design of those speakers, the speaker manufacturer uses products from the manufacturer of my interconnects, the speaker manufacturer uses speaker cable as one of their referenences from a manufacturer that uses their speakers as one of their references. This coupled with advise from different dealers that carry at least some of my components, the Cable Company and fellow Audiogoners has made a somewhat overwhelming decision more manageable. I also try to predict what components have the greatest likleyhood of being a basis of the system (either get the most use, have a greater importance or just may stay the longest) and try to prioritise cable auditions from there. Of course I'm still open to recommendations from those I respect.

IMHO the need to use "ONLY" the same brand of IC's and cables is a myth circulated by manufacturers and salesmen. As synergy is an issue with combining components and speakers so it is wiring issues. The components you are using and the sonics you expect will dictate the brand/type of wire you select. There are just too many variables involved for such a rule to be valid. Been there, done that! :-)

IMHO the need to use "ONLY" the same brand of IC's and cables is a myth circulated by manufacturers and salesmen.

I agree fully. This is also not the "ONLY" myth associated with IC's, Cables and power cords....there are many more. Why are these myths perpetuated? Probably because some audio components are not robustly designed as to be largely imuune to these minute changes in power or cabling. IMHO, they ought to be. Frankly a good design should not be influenced by miniscule resistive, capacitive and inductive changes of one high quality speaker cable to another. Frankly a good power supply design should not be influenced by dirty power. Frankly a good circuit design (allowing for true balanced and XLR shielded connectors with low output impedance and high input impedance) will usually prevent audible differences between one connector and another.

Instead manufacturers use unbalanced designs (higher noise), cheap RCA cables (often no shield but, of course, GOLD PLATED), amps with very high output impedance (making speaker cables quite influential) and low cost power supplies often relying on cheaply sourced parts that may not have high QC standards.

The end result is that different cables cause no end of sonic wonderment when stictly speaking they should have inaudible or at the most minimal impact.