Interconnect Cable Length

Thank you. Unfortunately I don't have balanced input/output on either of my devices and they are currently 1.5 meters apart. My spacial limitations are based on the fact that I'm currently using my in-wall speaker wiring - 12 gauge, and each run is roughly 25' from the amp. I can forego the current wiring and move the amp closer to the speakers by using ~15'-20' interconnects. Realistically, I don't need 12 meters cable, more like 7 meters. Just as an aside, I had mentioned this in another thread that I'm seriously considering purchasing a pair of Cary SLM-100 monoblocks from a friend and I was warned against running 25' speaker wires with those amps. They do have much higher input impedance - 150K ohms, so that might help with the interconnect length. Ideally, I should move the entire audio system including all the sources to the opposite side of the room near the speakers but that would require significant redecoration and technically not an option, not at this time anyway.

Just a quick update and another question. Since my last post I read up some more about the Carys and their very high output impedance and decided to go with a solid state amp and bought a perfect condition, recently serviced McIntosh MC2200 stereo amp. It sounds beautiful. Here is my related interconnect question:  assuming very high quality cables, do you guys think there will be noticeable difference between a 3 meter and a 6 meter interconnect lengths? As a reminder, the preamp output impedance is 75 ohms and the MC2200 has a 100K input impedance. Thanks again.

Thank you guys for your input. The 6 meter cable is an Onix Master series that retails for $1800. I bought it for quite a bit less along with the MC2200 amp. I did an A and B test comparing it with my 3 meter Pangea cable (paid $150) and could not tell a difference. I have it all now hooked up with my preamp driving two separate amps and pairs of speakers in two adjacent rooms. I must say the Onix cables were probably built for professional use since they are about 5/8" thick with an almost indestructible shielding. Completely overkill.