From another thread:
Originally Posted by halsan40
I did buy a new Yamaha Center model NS-C525. I checked the specs and it is 6 ohms. The rest of my speakers are 8 ohms. Could this be the problem? I have my receiver set for 8 ohms. Should I set it to 6 ohms?
funny you mention this (impedance switch), I just happened to read a review article, from "soundandvisionmag.com", on the RX-V2600 receiver, and the final paragraph had an interesting comment (shown below). It essentially claims that when driving low impedance loads (or speakers), with the switch set for 6ohms, the receiver shuts-down. However, it works fine, driving 4 or 6 ohm speakers, with the switch set for 8ohms. Moreover, the receiver drives low impedance loads very well, with power to spare, apparently (only a weird flaw with the impedance switch function).
Therefore, I bet there's probably a good chance your receiver will function fine with the impedance switch set for 8ohm's. Good Luck!
(quote, taken from SoundAndVision article)
"The Yamaha RX-V2600 delivered near-benchmark performance on every test, and literal benchmarks for linearity (0 error at -90 dB) and PCM signal-to-noise, which measured -75.7, the theoretical ideal for our dithered-silence test. Power was impressive for just about any common real-world speaker load, including all-channels power. The receiver shut down when confronted with high-output/low-impedance stresses with its impedance switch set to "6 Ohms," but did fine on the same loads with the switch "mis-set" to the 8-ohm position."
Samsung HL-R6168W, Polk Audio RM7500, Dish DVRs(622/722), Yamaha RX-V2600, Panasonic DMR-EZ17, Panasonic LX600, ChannelMaster 4228, custom HTPC.