Soundhound,

Does your analog hiss increase with volume or trim? In mine, the hiss increases during the setting (via the calibration menu) of trim, but after the trim has been set, the analog hiss stays pretty much the same. Also, in mine, the analog hiss is not much different with the volume knob at -79 db as with the knob at -1 db. In analog, the hiss is just, well, there.

Will - When I increase and decrease the trim or calib, the hiss raises and lowers (in analog) At -15db in the trim or calib menu, it is REAL quiet, as quiet as it is in digital mode. The hiss is also volume control dependent. It seems to stay the same after I exit the menus. Since I thankfully don't have to run the trims above 0db, the hiss in my unit is acceptable, but not stellar. Generally, the hiss is only audible about 5 feet from the horns. I sit at 15 feet from the speakers. I have some analog preamps that are certainly quieter, even a couple that use vacuum tubes.

Well I hate to say it, my unit hisses quite a bit. Just got it yesterday, so I haven't fully calibrated it, but in stereo mode, the speakers hiss with nothing playing. The center is the loudest. I can hear the hiss from more than 10 feet away. The other 4 speakers hiss, but I cannot perceive if I can hear them since the are drowned out my the center hiss.

The hiss seems to be unrelated to volume setting. I turned the trim levels down 3 dB, but the hiss didn't change either. Plus the trim settings should do nothing in stereo bypass mode, which I was using. I disconnected the interconnect from the amp channel and the hiss dropped to almost inaudible levels (had to be within 6" to hear anything, which is great performance).

So, if I turn the system on but don't play anything and walk into the room, I hear hiss. Sure, once the music starts it is mostly drowned out. I'll have to do more playing around this weekend. I am pretty sure listening to music quietly or during quiet passages would be enough to let me hear the hiss.

Anyone else have this problem and figure out how to solve it? Worst case seems to be either buying a more expensive unit that has quieter cicuitry, or buying a 2 channel analog preamp for my music listening. With the latter I can leave the 950 off when listening to music, keeping the center and surrounds quiet. Of course I would much prefer a quiet AV preamp.

Applejelly:
Bummer. If you hear a hiss with just the 950 connected to your power amp, that goes away when you disconnect the 950 from the amp, then something is definately wrong. In stereo bypass mode, there is very little hiss in my unit, and as you assume, the trims have no effect in that mode. Have you tried the experiment with all input devices disconnected from the 950, so that you just have the 950 and your power amps? If it hisses in that configuration, it is pretty damming for the 950. I really don't understand why this preamp is getting so many reports relatively speaking of hiss. I don't think this is a knee-jerk reaction of customers of the prior hiss problems either. It is not rocket science to make a quiet analog preamp, I know since I've designed my share myself, and it is not that expensive either. As I've said several times before, they should have left off the FM/AM tuner and put the money into a better analog section. Excuse me, I;m ranting.....

[This message has been edited by soundhound (edited September 27, 2002).]

Maybe they improved the hiss, but it's still there.

Too many of us are experiencing this for it to be issues with our individual systems.

But some people don't seem to have it at all. Maybe the 950 is just more sensitive to external factors (i.e., definately speaker sensitivity, and maybe amplifer gain as well) than other gear.

But I bet it's not meeting its specs in real world useage.

S/N Direct: 101 dB, Analog-DSP: 98 dB, Digital: 100 dB

Kevin C Brown,

I concur. Feel free to peruse this thread: http://ubb.outlawaudio.com/ubb/Forum15/HTML/000513.html

I have a vacuum tube 2 channel preamp in line with my main left and right speakers that I use as a pure stereo bypass _after_ the 950. It's _real_ noise is about -85db ref .775v, non-weighted (I measured it myself), and it has 20db of fixed gain. It is dead silent in my system. 'Nuff said.....

It's not dead silent in analog in my system. If you'd like to hear the problem, since we're in the same city, you are welcome to schedule an appointment to come to my home and hear the hiss in mine for yourself. You may bring your own cables to see if that makes a difference, and you can bring your isolating power supply and amplifier, if you wish as well.

Will:
I actually would be interested in hearing the 950 in your system. Why don't you Email me, and we can set up a time etc. soundhound@earthlink.net

OK, I finally got around to actually measuring the noise from my 950 in analog mode. The results are, with the volume at "00db", and the trim at "0db" Note, that I only measured the left front channel, as I would assume the others would be in the same ballpark noise wise.

Unweighted, full bandwidth, re.775v: -75db
With a 20kHz bandwidth limiting filter in-line with the voltmeter: -82db

Hardly meets the specs I'd say unless they are measuring the noise referencing some other voltage which would have to be pretty high. These numbers would be consistent with what I hear, hiss wise.

Using the stated reference level in the owner's manual of 1.5v, the S/N would be -88db, using the 20kHz filter, and -81db full bandwidth. Using 2.0v as a reference would improve these numbers by about 2.5db.

[This message has been edited by soundhound (edited September 27, 2002).]