This thing doesn't have a "hum" problem now, does it?!?

By the way, has anyone else noticed substandard home theater performance, as Scott G. has?

There's always the possibility of inductive coupling of hum from the power transformer in a nearby power amp or another component into the 950, or it's interconnects. The test for this would be to move the 950 a foot or more away from it's present position and see if the hum varies, moving the interconnects around too. It would make sense that switching to a matrix setting would increase the relative hum, since the signal is being sent to more of the speakers. Like I mentioned before, both in my installation, and looking at the noise floor on an ocilloscope, there is no hum present in the ouput of the 950s i've had.

Anyone who wants to hear the hum who lives in Los Angeles is welcome to visit me and can move the 950 around and vary the interconnects and try different experiments. Maybe there is a simple explanation to why mine hums when the volume is loud.

Will:

The moving around of the 950 is pretty easy to do; you could move it sideways to another shelf, or to the top of your TV to see if anything changes. The hum has to be coming from _somewhere_,it is just a matter of eliminating as many possibilities as you can by unplugging things, seeing if it makes a difference, then proceeding to another input. If the hum bothers you enough, it's really worth trying to find the source. I have a persistent but very low level hum in my system I've been trying to track down for weeks, months. I know it's coming from the crossover and power amp section, not from anything upstream. I've taken the crossover apart, measured and looked at the power supply rails on an ocilloscope - nothing. I've built a DC regulated power supply for the filiments of the vacuum tubes in the single ended triode amp - gets rid of a slight buzz I had in the tweeter horns but no effect on the basic low level hum. I've encased some elements of the filters in the electronic crossover with layers of "co-netic" magnetic shielding foil - again, helps lower the hum, but it's still there to some extent. This kind of stuff can drive a person nuts, so I know how you feel!

Will- Did you ever try to attach a ground wire to the 950's chassis?

I also get a hum from my 950, but I can only hear it if I put my ear up against the speaker at any normal listening volume. (Don't use much DSP except for the CES modes watching movies...) My 1st 950 also hummed, but I didn't recognize it until I got the 2nd one, because the hiss in the 1st one "overrode" the hum.

I did finally run my cable TV line through an isolator in my balanced power AC unit, but didn't help much more than the kludge solution I had before (run the cable coax line through a 300-75-300 ohm conversion; or maybe vice versa).

Do you have any really long interconnects going to your amp? you could also try to make sure they're not really close to any power cables....

And sometimes things as simple as getting a ground lift 'cheater' plug for the 950 or other components may do the trick.

Then I realized I had somehow lowered the master volume to -7 from 0.

Applejelly when I had this occur once I realized while in Speaker calibration I had jumped to using the ‘main’ volume controls on the 950 remote. (Upper ¼ right quadrant) as opposed to the < > buttons at SEL/PLAY to move dB while in speaker calibration. This will screw up your levels and confuse for a sec, when you go round the horn again for a recheck of test tones.

Well I figured out my first problem - the apparent drop in loudness after the inital calibration. That darn Rat Shack meter eats batteries pretty good. Seriously, once I put in a new 9V, the measured loudness went back up. So another calibration (00 volume, 75 dB) and my settings are back in the -8 to -11 range.

The hiss and hum is definitely volume related and only are significant at a volume of 00 and higher. Yes there are lots of reason for hum in a system, but nothing changed in my system except the blue dot. My old unit hisses, but never really hums and again, this is a constant at ALL volume settings. For the blue dot, is this a problem in practice? I am still not sure. Because of this I recalibrated at -10 volume (still 75db), hoping this would keep me further away from the nasties. Then again, I (obviously) had to up the trims, so maybe it is a total wash. I will keep experimenting and let you know. I do know that with it cal'd at 00/75, I was able to clip my amps with the volume set at 00 during the opening of Toy Story 2 (when the words Toy Story 2 come flying forward). So it seems like there is enough gain - or I need a bigger amp

Finally, the clicking mute circuit is definitely annoying. Any totally quiet part of a DVD (like the FBI warning or a silent menu) and I hear it. Pause the DVD and click. Rewind the DVD for more than a second and click. I can handle it during the speaker cailbration, where each channel change makes a click, but during the movie - uggh.

I think the unit is quiet enough to not even need the mute circuit. I guess they wanted to be sure it wouldn't hiss when just sitting there (set on a digital input anyway). I wish they hadn't gone that far. I guess I have a few more days to decide what to do....