Your Klipsch speakers probably have horns, and therefore are very sensitive. It sounds like your interconnect problem was caused by corroded or dirty RCAs. You might investigate replacing them with some good, though not extravigant gold plated new ones, or try cleaning the ones you have with alcohol or electrical contact cleaner. The hiss might very well be a gain structure problem. Start with just the power amp connected, and nothing else. If no noise, connect the 950, but make sure the volume is down all the way on it. If still no noise, bring up the volume on first an unconnected input, then try inputs where you have things connected. The object is to try to isolate the component which is contributing to the noise. If your power amplifiers have volume level controls, you might lower them some to see if that helps. Generally, first start by going through the loudness calibration procedure in the 950 manual (I assume there is a procedure in there somewhere). Since your speakers probably have horns, you will need to be a bit more careful with the levels of the power amps, and the gain trim settings on your 950. You might try to confirm that the individual channel trim settings on the 950 are at 'zero'. Then set the 950 volume control to 'zero' Play the test tones on the 950, and with a sound level meter (from Radio Shack - the one with a meter verses a digital display) set the meter to "C" weighting, and "slow" response. Increase the level pots on your power amp (assuming you have them) until the sound meter reads 75db for each speaker. Doing it this way assures that the 950 is not providing more gain than your system needs, and the gain structure of the whole chain is going to be close to optimum.