Quick question:

Got the new blue dot and there is less hiss, but it has a buzz. I calibrate at 75db and when the vol get close 00 the buzz is very very very loud. Hook up the original 950>>> NO BUZZ... My old nad equipment NO BUZZ.... Hard to believe it is my home wireing when my old equipment and my old 950 don't buzz at all.

Any ideas???

later bp

There should not be any loud buzz at all. The most I can hear with the volume cranked to +10 is a soft hum that is less than the relative level of the hiss, which is way down there in level. I have to put my ear _in_ my horns to hear it at all. If you hear more than this, I would call Outlaw directly and see if they can be of help. You might have a grounding issue, or maybe an interconnect that has a poor ground. Make sure you are listening to an input that does not have anything connected also, as the buzz could be coming from a source component.

bbpj,

You are not alone. Others including me, hear a buzz or hum from the blue dot 950 at higher volume. The hum gets loud in my system like it does in yours. Maybe it can be fixed by moving things around. I have tried things like keeping it in stereo and playing with the grounding without success. I also have invited others here to see if they could make the hum disappear. But so far at least, the hum remains in my system.

However, there seems to be less hiss at low volume in analog mode from my blue dot 950 than my old red dot, which is a good thing!

Will


[This message has been edited by Will (edited January 14, 2003).]

Will:

I know you are obviously hearing hum from something. If it were as loud as you say in my 950, I would have no problem hearing it from my horns. Have you compared the hum _relative to_ the level of music on the blue dot 950 verses the old one? This would at least establish if the hum is higher by the increase in gain of the blue dot. Is the hum louder, less loud, or about equal to the level of the hiss, at "0" and "+10"? This will give a rough indication on the level of the hum. Is the hum only audible at "+10"? If so, how loud is music when you play it at that volume? How loud is the 950's internal test tone when the volume is at "+10" (after you have done a normal calibration at "00")? If you give me this last info, I can set my 950 to the the same level of the test tone with an SPL meter and see how audible any hiss/hum is.

With the blue dot's volume around -06 the hiss becomes instantly noticable and increases as the volume increases. Initially there is no noticable hum but that soon changes. Increasing the volume to around 00, the hum starts to overwhelm the hiss in my system. The hum gets louder as the volume goes up further. While in my regular listening the volume is usually much lower, I sometimes listen with the volume above 00 and sometimes even above +05. The blue dot is louder than my previous red dot, with trims set to zero but I did not have the trims set to zero with the red dot.

As I recall, Soundhound, you have a new hiss-fixed 950 and not a blue dot (rebuild) 950. There may be differences between individual units. As you know, and I'm grateful you did this, you measured a large difference in S/N between different red dot 950's in the past.

There may still be individual differences in the 950s, as well some environment being more hum inducing than others.

With my blue dot 950, the trims are set close to zero in all channels except the subwoofer. However, with the previous red dot 950, the trims were set much higher, which was necessary to get the red dot to go sufficently loud.

I have not calibrated my system, but I'm playing mostly in stereo. Others who have calibrated their system hear a hum at higher volumes. I know I should calibrate, but I'm not sure that will fix the hum.

However, fortunately when music is playing, I don't consciously hear the hum or hiss.

[This message has been edited by Will (edited January 14, 2003).]

I sometimes listen ….even above +05.

with a Sunfire Cinema Grand? And Klispch High effiency ?
Notice a slight ‘ringing’ tone to that hum.

Will, thought of memory what year/model is your SCG amp?

I don't have Klispch speakers. My speakers aren't THAT efficient. Also, +05 volume level is used sparingly and only on select music. I wouldn't crank +05 for the 1812 crescendo. If I did I'd likely lose my hearing or my speakers or both. But for a particularly quiet Moszart or Bach chamber piece that I want to hear louder than life, sure, why not! Incidentally the +00 volume level is used far more often than the +05 level, even though I keep it under +00 most of the time.

I have the older, original Sunfire Cinema Grand from a few years back, not the newer Signature, which is more powerful than mine. Don't remember off hand the exact year mine is.

Incidentally, I understand the risk of blowing an amp or speakers or clipping an amp is greater with underpowered amps than an overpowered amps.

Will: -Whoops on the Klispch.. and was teasing on the volume, would have to have an awfully big space for that 1812 at +5 but…. wouldn’t it be something…just up until you went deaf!

Seriously, Will I’ve been following your various hiss (now hums).
My info may be outdated resolved,etc but when I saw you mention you had a CG amp this week, it rang a bell on a memory of some info I had run into on Carver amps way back when I was looking for Class D or hybrid-like tech. I ran into this on the Sunfire Cinema Grands ( also affected were the ‘Signiture’ release of the CG) and another Carver design release I can’t remember. I pulled this from 2000/2001 consumer reviews.
These (hiss/hum)issues appeared in ‘some systems’ but not others, - with theories it could be traced in some systems to interconnect interactions, various model pre-pro/reciever interaction with the CG, etc. Some posters mentioned …the issue did not occur until they changed/added in their AV setup. Most posters who had these issues often never returned their amps (due to their great satifaction with the product) but attempted by tweaks/changes in their systems to minimise impact and declared their intention to "live with it" due to the great preformance/sound of the Carver design.


(Start Quotes)
Reviewed by: Gary , Audiophile, from los angeles,ca
Product Model Year:2001
…….btw, I also had that damn buzzing/ground problem……….
--------------
Reviewed by: Chris Immormino, Audiophile, from Roy, UT
……when I first hooked up the unit I had a hum from the center speaker with my preamp in stereo only mode. Disconnected the cheap RCA cable I had used to connect the center and the hum went away. Replaced the interconnect with a Kimber cable Hero interconnect to match my mains and the problem is gone. I suspect the unit is very sensitive to interference and ground loops.
-------------
Reviewed by: Adriano , Audiophile, LA
……… I am deeply bothered by this very audible hum. I thought it was an isolated problem until I read ….
Major humming. Problem…..
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Reviewed by: Jeff , Audiophile, SJ,CA USA
….When it was in standby, there was a hum coming from the amp (i.e., from inside the box). When it was on, there was a very obnoxious hum from all five speakers that clearly audible, even over music.
I was so bad that I thought mine had to broken. I returned it to my dealer, who let me borrow their demo unit to see. The demo unit was marginally better (hum not has bad, and not as bright), but still unacceptable. Thankfully my dealer allowed me to return it. My dealer plugged mine into their system and told me that it appeared to be fine.

My take on all of this is that the CG is VERY dependent on system matching, even though everything I tried couldn't solve its problems in my system.
On the plus side is that the CG through an amazing soundstage
---------------


Posted by Anthony 9- 20 -1999 Using Mozilla/4.0 (compatible; MSIE 4.01; Windows 95):

This weekend I just purchased the new SUNFIRE CINEMA GRAND SIGNITURE AMPLIFIER...I was an earlier owner of their CINEMA GRAND AMP.... It was not so apparent with the earlier Cinema Grand amp but now I hear a slight "hum" from the speakers when plugging in the new amp (is it quite possibly because this amp is so much more powerful and/or this amp has a 3 prong AC cord. My room is rather small so I am close enough to all my speakers and components to hear this hum in quiet passages of film soundtracks(mostly when there is just vocals present without background music or effects:especially T.V. news broadcasts)…
------------------
Audio Revolution. -Sunfire Cinema Grand Series II Architectural
Reviewed by Jerry Del Colliano - July, 2002
The Downside
Despite design changes to make the amp more quiet relative to a signal to noise ratio, I still find the Sunfire Cinema Grand Series II to be noisy in comparison to amps that don't employ the Tracking Downconverter concept. If you want the power and the finesse at this price without the heat in a small package, you have to sacrifice something and that compromise is a tiny fraction more noise than you will hear on a Proceed AMP5 or other amps in the Sunfire Cinema Grand Series II’s class. For home theater applications, I don’t think this amount of noise is much of an issue, but for extremely critical musical listening, especially on more sparse productions like some jazz and small-scale classical albums, audiophiles might object to the ever-so-slight hiss
---------------------
Posted: June 28th, 2002
Andrew_Ballew
AVS
The ONLY component in my theater that has a 3 prong cord is the Monster HTPS 7000 Power Center. EVERYTHING else is two prong- my Carver amp, Rotel pre-amp, both powered subs, dvd player, etc. etc. My cable is grounded properly as well, so it is not the source.

I still have a slight hum or buzz from my speakers, even with everything off but the amp. So, I can only assume my hum comes from its internals, or the hum is introduced after the amplification stage in the speaker wiring. The hum still exists even when I unplug all input wiring to the amp.

(End Quotes).

Any possibility this could be playing a role in the level of your hums/hisses??

Don't mean to get too 'techy' here but I have noticed some equipment is prone to ground loops / oscillation / hiss, and this can usually be cured by assuring that there is a build-out resistor in the sending component's output. 100 ohms works well. This resistor isolates the 'hot' lead between components and generally cures these interactions. I don't recommend opening up you components to do this, but if you are really handy with a soldering iron, a 100 or so ohm resisor can be inserted in line with the 'hot' lead of the interconnect. I don't know if the 950 has any resistors on it's outputs for isolation, (it's common engineering practice to include them) but I do not have any of the problems Will has (but then again, I have tubes )

Folks,

Sorry if my reply is not technical enough for you but...

Almost any system is capable of generating "hum". In my many years of playing around with lots of different gear I've had it happen to me many times.

In some very rare cases it has been a defective product. So the first step is always the manufacturer / dealer etc.

But in a lot of cases they'll fire it up and won't hear a thing - because the problem is with your "system" as opposed that one piece of gear. And your system includes just about everything connected to your home's electrical system - from the breaker panel on in.

In my current set-up I'm using many pieces of gear (24 or more individual components). One of the things that I noticed last year (after I added an ICBM by the way) was a growing problem with hum: some fixed, and some variable. I tried all of the "easy" fixes; reversing plugs (where possible), separating (physically) components, keeping "power" and "signal" cables apart. Not running them parallel to each other etc. But the problem persisted. So I bit the bullet and bought an isolating transformer (sometimes known as a ground loop isolator.) It cost me over a hundred bucks (Canadian) at an electrical supply store for a fairly beefy unit but it cured the problem. In my case it turned out to be the four or five components that used wall warts - including the ICBM. To keep costs down manufacturers choose them over proper internal power supplies. To keep costs even lower they use really cheap wall warts. When I powered all of mine from the isolated side of the transformer the hum problem went away. I might have accomplished the same thing had I put my pre/pro (not yet a 950) on the other side instead. It may or may not work for you.

So my not-so-fancy solution to hum problems, when all else fails, is to try the isolating transformer route. You might even be able to borrow one from a supplier to see if it will solve the problem before you purchase it.

Hope that helps.

Jeff