Hiss of 950 in analog modes

Folks, I am a new owner of the 950/755 combo. So far I enjoy it a lot generally, but got one issue as the following:

I got slight hiss from the 950 while using any source in analog mode, it will disappear whenever I switch the input to digital coax. The hiss is only audiable from my front speakers (Dynaudio Audience 82 with 87db sensitivity) when I put ears very close (several inches) to them.

Is this normal for the final version of 950 (Blue DOT?)? Just wondering why there is no hiss from digital input, I thought the signal should be going through less circuits in bypass mode.

Any suggestions will be highly appreciated.

Thanks.

Ming

A certain amount of hiss is almost impossible to avoid no matter what gear is involved. At a distance of mere inches, I would not be surprised at all to hear a little hiss when there is nothing playing -- that would qualift as reasonable even with the "blue dot" 950. This hiss may be the unavoidable by-product of listening to silence at an excessively close proximity to your speakers (pardon the sarcasm -- it's been a long day already), but the fact that you are getting this hiss on analog inputs but not digital suggests to me that the hiss may also be due to interference picked up by the analog cables leading to the 950 (proximity to a power cable, etc).

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Gonk, thank you for the reply. Glad to know some electronic noise is unavoidable to most of the processors including Outlaw 950. The hiss in my system is very slight and not annoying at all, guess I must have paid too much attention to the hiss problem reported on 950 from reviews on the old version.

Now I will throw more music on the 950/755 and continue my evaluation.

I drew the conclusion too early yesterday about the hiss issue in my system. I forgot one important factor: the volume setting while checking the hiss level.

After reading more discussions at this forum about the hiss problem on 950, looks like after the Blue DOT fix the worst hiss level for a very sensitive speaker should be only audible 1 or 2 feet away with the volume set to +10dB.

When I set the volume on my 950 to +10dB and select CD as the source in the bypass stereo mode, I can hear the hiss 8 feet away at my listening position. I tried to power on/off the CD player, disconnect CD player from 950, disconnect all devices from 950 except the 755 so there were only interconnects between them. All these didn't make any difference. On the other hand, there are no any hiss (completely silent) when I switch to the digital inputs even if the volume is still set to +10dB.

I talked with Steve of Outlaw, he suggested me to swap the cables between CD player, 950 and 755, I will try that tonight and really hope it's simply a cable problem. On the other hand, can anyone tell me if you have experienced the similar thing with your 950? Do you folks think what I found here is within the "normal" range or not?

So far I really love the performance of the 950/755 combo, just try to get rid of the hiss issue. I would appreciate your opinions/suggestions very much!

Ming

I drew the conclusion too early yesterday about the hiss issue in my system. I forgot one important factor: the volume setting while checking the hiss level.

After reading more discussions at this forum about the hiss problem on 950, looks like after the Blue DOT fix the worst hiss level for a very sensitive speaker should be only audible 1 or 2 feet away with the volume set to +10dB.

When I set the volume on my 950 to +10dB and select CD as the source in the bypass stereo mode, I can hear the hiss 8 feet away at my listening position. I tried to power on/off the CD player, disconnect CD player from 950, disconnect all devices from 950 except the 755 so there were only interconnects between them. All these didn't make any difference. On the other hand, there are no any hiss (completely silent) when I switch to the digital inputs even if the volume is still set to +10dB.

I talked with Steve of Outlaw, he suggested me to swap the cables between CD player, 950 and 755, I will try that tonight and really hope it's simply a cable problem. On the other hand, can anyone tell me if you have experienced the similar thing with your 950? Do you folks think what I found here is within the "normal" range or not?

So far I really love the performance of the 950/755 combo, just try to get rid of the hiss issue. I would appreciate your opinions/suggestions very much!

Ming

When you have the volume control at +10db, you are running the 950 in an unrealistic situation. Assuming the rest of your system is performing normally, if you played a movie or CD at that level, you would blast yourself out of the room.

Any component will generate some hiss when it's gain is set to maximum.

I was one of the original prople who complained about the hiss problem since my speakers have efficiency of 106db/watt, which is way more than any consumer speaker you can buy. The current blue dot 950 is quiet enough so that the hiss cannot be heard at the listening position through these speakers.

If you are hearing hiss at the listening position at levels that are not unrealistic for even high volume listening, something other than the 950 is amiss in your system.

Thank you Soundhound for your reply. I agree that +10db is not a realistic volume, but can you please try this on your A/V system and let me know if you also get audible hiss at listening position?

I got this idea of testing from Gonk's 950 User Review, which is very informative and had helped me a lot in purchasing my new HT components, and some messages on this forum. It doesn't seem that there are other people who have the similar level of hiss with 950 after the Blue DOT fix.

I have tried to swap the cables between my CD player, the 950 and the 755 last night, but didn't see any difference on the hiss with all kinds of combinations.

Don't want to panic too much here about this hiss thing because it is not an issue at my normal listening volume, just hate to think I might have got a unit with defect and try to rationalize it.

Any other fellow 950 owners who could share your experience/opinions/suggestions with me? Thank you in advance.

If you do an archive search about the whole hiss issue, you will see that I not only explored every possible setting/configuration/volume setting etc, but I measured with lab equipment the noise levels of my 950 and those of other users. I evaluated the original blue dot prototype, again with lab equipment, and listened to it extensively.

The blue dot 950 presents no audible hiss at the listening position at any volume level where I could stand to be in the same room - and my speakers are as large as refridgerators.

As I said before, if you are hearing hiss at normal realistic listening levels, something other than the 950 is wrong with your system.

[This message has been edited by soundhound (edited March 10, 2004).]

What you are hearing is totally normal. Try it with your last receiver and I guarantee it will do the same thing. For your peace of mind I just turned my 950 to +10 and got a loud hiss as well (it completely disappears around -2), but that is not the hiss problem you have read about. I used to hear hissing at -40, but that was corrected with the blue dot. Like SH says, there is no way you will ever be listening to anything at that level, and if you do, I doubt you will ever hear the hiss again, along with anything else.

Edit: I just went and turned my Rotel Preamp to full gain, and guess what, hissing.

[This message has been edited by Jed M (edited March 10, 2004).]

I've had my 950 for about 2 months and have experienced no hiss problem in any mode at any volume even with my Klipsch speakers. There is no hiss at all from the listening position. Of course, like everyone else, I stuck my ear in the horn of one of the speakers and did hear slight hiss. This is completely normal for electronic gear and the 950 is actually quieter than my previous pre-amp, an Acurus L-10.

The 950 is a very nice piece of equipment (especially for the money). SACD/DVD-Audio sound superb and even stereo sounds so musically satisfying that I'm re-discovering all of my old CDs.

Sit back, relax, and enjoy!

The reason you're hearing hiss w/ the analog and not the digital is because in some version of the 950 (maybe the blue dot?) outlaw introduced muting circuits on the digital signals. So, if a digital input is not receiving a signal (the CD player is off or on pause), the muting circuits click in and you get silence.

The "hiss" you speak of is completely normal and you won't ever get rid of it. Nor should you expect to. *MAYBE* if you upgrade to a top-top quality pre-pro (maybe top-end meridian or something similar) you might get a little less hiss, but it's there in every piece of gear. My brother-in-law owns a Lexicon MC12B, uses balanced cables from mc-12 -> amplifiers and a PS Audio PP1000 to supply "super-charged" rejiggered power to both amp and preamp, and if we turn up his volume to the max setting, there's some audible hiss at the listening position.

So, don't worry about it.

There are a few things you can do to lower your noise floor though. One is to make sure that all your power cords are seperated and not touching any analog ICs. Another is to try a balanced power unit. I was surprised, but I recently hooked up a BPT Ultra 1 balanced power unit into my system (balanced power units use a transformer to condition incoming power from the wall and then sends 60v down the hot lead and 60v down the neutral lead, instead of the normal 120v down the hot lead and 0v down the neutral, you can read about it various places). I now feed all my equip. except my amps off the BPT unit, and I noticed a pretty good reduction of the noise level.

Sorry to repeat if somebody else mentioned this, but did you try recalibrating your 950 with a SPL meter? If not, go down to your local Radio Shack and pick up their analog SPL meter. It should cost you less than $40. Then try recalibrating with that. As SH and all the posts above point out, if you're still able to sit in the room, after recalibrating, when listening at those high levels, something is definitely amiss.

Whew! Thank you, soundhound, Jed M, seattleguy, jgubman and Jason J, what you said make me feel much better. My situation is similar to what Jed described, the hiss disappears at the listening position while the volume is reduced to around -2dB. Based on all I heard from you, this is not something I would worry about any more. Just received my center speaker (the last piece of my HT system) today, cannot wait to start the evaluations with DVD movies.

Jason, I already got a RS SPL meter and calibrated my speakers following the instructions on 950 user manual. Both of the front speakers were set to -10dB.

Soundhound, I could not find your post about the 950 testing with lab equipment, can you do me a favor and provide the link? I am curious to know what you had done and found.

I would also like to extend my thanks to the whole forum, here I got answers to many of the questions I had during my research process. This is also one of the major reasons I decided to buy from Outlaw.

mhua, if you find yourself needing to turn your 950 up to 0 or into the positives you could always recalibrate to -20 to give yourself more headroom. I think I actually calibrated at -25 @ 70db, so I am usually hanging out in the high 30's when watching tv.

The hiss issue was discussed around the summer and fall of 2002 if i'm not mistaken. If you're interested, search around that time period. Unfortunately, the search function doesn't work any better for me than anybody else.

Jed, I have not tried to recalibrate my speakers at any volumes lower than 0dB. So far the highest volume I have ever played while listening music is around -7dB and it's already pretty loud to me. However, more headroom is always good, just wonder why Outlaw and many people think the calibration with 00@75dB is the best, will this bring any benefits to sound quality?

jgubman, I forgot to mention that your explanation about no hiss from digital input makes sense to me. And thank you for the noise reduction suggestions.

soundhound, if your post we refer to was submitted in summer or fall 2002, that's maybe exactly why I could not find it. It seems that you can only retrieve the posts at this forum no further than one year.

Bummer!

The only reason for 75db calibration is so that when you play a DVD at "0" on the main volume control, the sound pressure level will be the same (in theory) as the film was originally mixed at.

Have you checked the 950 Archive ? There are posts in there from back into 2002.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Yes, seems that the archive contains all the old posts. I found the one soundhound mentioned back to September 2002, lots of very good discussion there about the hiss issue. Thank you gonk for the info!

soundhound, thank you for the explanation on calibration.

Looks like it will take some time and learning to become a real "Gunslinger".

Correct me if I am wrong, but it makes no difference whether you set your reference level (calibrate @ 75db) at 00 or at -30 on the dial. Its just a measure of output.

Thanks for the reminder of the archives Gonk. I went back and read a few of the classic threads. I wonder if Ricky is still among us.

There will be some main volume setting at which you would not be able to achieve the 75db by just adjusting the trim levels. I think I calibrated mine at the -10 setting which means most of my trim setting are in the -2 to +3 range. Everyones would be different.

The gain structure of the 950 is optimized for calibrating with the volume control at around "0" and for SPL of 75db. Going beyond these norms can either cause degradation of the signal to noise ratio or lack of enough range in the adjustment trims to achieve a balance between speakers.

mhua,

I purchased a 950 last year and thought the hiss issue was resolved. The hiss was audible 8 feet away on all inputs (but especially with analog) with the volume set at 0 dB. Rather than send it back for another one I returned it. My old Denon receiver was completely quiet. My Aragon Stage One is also extremely quiet. You may need to return the unit and try again.

Now that is hard to believe with a properly calibrated system. My speakers are 106db/watt efficient and I can't hear hiss from that distance. I seriously doubt your speakers are more efficient than mine.

There are only two variables that would make the hiss more or less audible with a properly functioning 950:

1) The efficiency of the speakers. This is assuming there is nothing in the speaker's design which boosts the high frequencies beyond what would be flat response.

2) Proper calibration. If the calibration is improperly performed so that the 950 is providing more gain than is necessary for 75db SPL at the listening position using the internal test tone, then hiss will be audible.

Soundhound,

I do respect your experience in the field and your experience with audio equipment, and you don't have to believe. I calibrated my system with a radio shack meter, used expensive interconnects and speaker cables, ran a dedicated AC line just for the audio, and a Monster 3600 filter for the whole system. My point is that I believe the unit probably was defective and sent it back rather than try a new one. I believe Outlaw would have exchanged it, no questions asked. The original post from mhua asked if the issue was still a problem and for me it was. Outlaw is a great company. This forum can make it appear that there are more quality issues than there really are because it is open. roblinds said it best. There are different kinds of people out there with their own agendas. I don't have an agenda. But, I stand by my original statement. Once I exchanged the 950 with the Aragon, the hiss was gone. The problem has not completely gone away.

tgrisham, thank you sharing your experience with the 950. The hiss issue is not severe to me in normal listening condition, at 0dB the hiss with analog inputs is audible at around 2 feet way from the speakers, it would start to become more annoying while the volume is going higher from there. At +10dB, I can hear the hiss from the listening position (8 feet away). There is no hiss at all for me with digital inputs.

Based on what I heard from many of the 950 owners at this forum, this level of hiss seems well acceptable. Other than this issue, I am pretty happy with the 950 performance after my two weeks' ownership. Will continue my evaluation with all different music I have for another two weeks, and see if anything would come up to change my mind.

Your Aragon Stage One is a great pre/pro, continue to enjoy it!

Recently I did a little test. During the viewing of a movie, I pulled out the good ol’ RS analog meter and set it up at the listening position. I then cranked up the volume on the 950 so that the SPL was swinging just past +116 dB during heavy explosive rumbling. Granted, most of that SPL was coming from the subs, but it was in balance with the rest of the audio spectrum. I then stopped the DVD and selected a non-digital source. I approached the right front speaker ear first and noted that the point at which I could discern hiss was less than twelve inches from a tweeter.

remark – I think that if I had used enough gain to make the hiss audible at my listening position and then began playback of program material, I would have to report: “I hear a high pitched ringing at my listening position, even when my HT gear is powered down completely!”

First off, any hiss that I can detect at any position, at any level, and from any speaker, I can attribute to another device in my system other than the 950. (It's usually my analogue equalizers that are the culprit.) The 950 is simply dead quiet.

Since this thread has also touched on calibration (as have others in the Saloon) I've got a bit of a nagging question to ask - especially of Soundhound since I'll use his system as part of the question.

I run fairly efficient speakers across the front - 96dB or so. That's 10dB less than what Soundhound has posted - and probably 5-8dB more than your "average" speaker.

I get an SPL reading of 85dB in my system when I set my 950 to -10dB AND with the front L/R calibration set at -5dB. Without individual gain controls on my amps (well, all but one) how the heck would I ever hope to calibrate for 85dB at a "0" setting" on the 950 - let alone 75dB? There just ain't much more "calibration" level left in the 950 to back off on. If I had Soundhound's speakers I'd be 10dB further away.

I can only conclude that it would take a combination of i) lower efficiency speakers and/or ii) lower set amplifier gain and/or iii) actual power amp gain controls, to be able to hit either 75 or 85dB at a "0" setting on the 950.

Soundhound: can you crank the gain down on your amps to hit these targets? If not, how do you do it?

In any case, hitting 85dB at a "-10" volume setting on my 950 leaves me way more than enough left at the top end (anything beyond -5 to 0 is just way too much for these old ears) and plenty of room to reduce the level to clean background "reading" levels.

Regards.

Jeff Mackwood

Jeff:

I have installed input level controls on my amps that didn't originally have them except for the amp that drives my high frequency horns. On that amp, I lowered the gain to less than unity (an actual voltage loss!) by replacing the input tube with one which has lower gain.

When I calibrate the 950, I set it's trims at "0" for all channels and the main volume at "0". I then do all the level adjustment with the volume controls on the power amplifiers.

If I had to rely on the trim settings in the 950 with my efficient speakers, I would never be able to get anywhere close to 75db.

Thanks Soundhound.

You confirmed what I suspected - and that I was not missing something else really obvious that the rest of the world knew - and I didn't. (Hate when that happens )

Regards.

Jeff Mackwood