The speakers, according to Paradigm, are"compatible with 8 ohms". Pretty vague, I guess. Mine measure between 3.8 - 5.7.

I have moved the wires around to all the channel outputs, ran combinations of fronts only, rears only rears & sides, etc. While it does takes longer to "thermal" with less speakers connected and in various combinations and locations on the outputs of the 770, it still does.

Measuring the output voltage while running? I don't know that I can tell anything from that - not an engineer by any means. The voltage at the receptacle
stays right around 115-117 vac using a meter, at the levels I have been testing at.

Is a controlled load that a tech would use for bench testing the same as actual speaker loads that vary with music?

Is the resistance variance in my speakers enough to cause a problem? Either way, I have had only the ones with the same measured impedance running at once during this anyway.

I've spent a little time thinking of a way that some type of measurement information from you would allow me to know if I'm recreating the about the same level of output as your 770 is experiencing, but haven’t thought of one using measuring devices that aren’t very good at audio frequencies. Perhaps an easy way to drive all channels equally at 60Hz so that the 770’s outputs can be measured accurately with common AC measuring tools. This would require setting all speakers to large or setting the crossover points low enough for all speakers that 60Hz is not routed away from the 7 speakers. If so, you could determine, for example, that at an output of 18 volts AC on all 7 channels, it takes 14 minutes for your 770 to shut down thermally.

My guess is that your speakers that measure about 3.8 ohms DC are probably about 6 ohms at low frequency AC, and the ones that measure about 5.7 ohms DC are probably about 8 ohms at low frequency AC. That would mean that, at 18 volts RMS AC, the 6-ohm speakers would have to sustain a continuous 54 watts and the 8-ohm speakers a continuous 40 watts without damage until the 770 shut down. I don’t know if that would be good for the drivers. Anyone with speaker driver experience want to comment on that idea before we attempt this?

I’ll be away from the computer for a few days, so I check back next week.

As far as a source is concerned, one could use the tone generator in the True RTA program to find a steady 60Hz tone. Even the free/trial version of True RTA has a working tone generator. So if I feed a signal from a PC running True RTA into the 950 in Stereo7 mode and make the proper adjustments, I should be able to get a nearly identical voltage level from each output of the 770.

I’m still not sure about running a continuous 40 or 50 watts into a speaker’s voice coil, even if that speaker is rated to 300 watts.

How long does it take to make an adjustment?

Hi again to anyone that was interested in my problem back then(or now). I have not gone any futher with any testing.
While I have watched a lot more movies using the system, I have not done much more music listening. I have only recently added cables for DVD-A and hope to get back & try some more testing using that format.
I have not tried BB4TB's testing advice butI still think that I will install a fan for the 770.