# Is Your System's Noise Floor Low Enough?



## AudiocRaver (Jun 6, 2012)

The funnest discoveries are the surprises. Like setting up a pair of speakers and accidentally getting a monster soundstage. Like discovering that the openness of a soundstage can be affected by a system noise floor level that you can not even hear when no music is playing.

The latter example is what I ran across in just the last couple of weeks, and it has been great fun figuring out what is going on and how to improve it and hearing the resulting improvement.

*Some history:*

My laboratory :dumbcrazy: is divided into two areas, and the Music Server is in one area while the Receiver and Speakers are in the other, the listening area. The power all comes from one set of outlets from a single breaker. A Uninterruptible Power Supply (UPS) powers the Server and provides surge and noise protection for all the rest.

A couple of years ago I realized there was a noise floor problem - quite a bad one - with the line-level signals running from the Music Server's Audio Interface to the Receiver, a stereo pair of 15-foot RCA-to-RCA cables. It was bad enough that I could just hear the noise at the LP at higher listening volume settings with no music running. At normal volume level settings, I could hear it when I moved close the the speaker. It was mostly hiss with a little bit of 60 Hz hum. I had tolerated it for a couple of months while I selected and ordered some TOSLINK optical cables and a powered TOSLINK selector/splitter.

When I got those parts and set them up and switched over to TOSLINK, I was completely blown away by the difference. Of course the noise when the music was not playing went away. But the bigger benefit was that the openness of the soundstage was transformed. The areas between sound images in the soundstage went from _cloudy dark_ to _deepest black_ sonically. The difference was striking.

The lesson was that, although I could not hear the noise directly when listening at any level with music running, I could _perceive_ that it was there in the lack of clarity and openness of the soundstage. I went back and forth numerous times between configurations to verify that I was not imagining the effect. Obviously, the RCA cables were ditched and it has been optical ever since. Until......

*Current System configuration:*









The diagram shows my current system configuration, which has evolved over time. It is worth noting that at the time I configured Dirac Live in both of the DL devices, there was project file compatibility between the two versions (miniDSP nanoAVR DL and Dirac Live PC Full), and the same set of measurements was used to generate the DL filters in the two devices. (This is no longer possible.:crying

Most of my serious listening has been done from the music server, with the Bluray being used mainly for movies.

*Recent Discovery:*

The Bluray has USB ports on front and back. The documentation does not say so, but I wondered if it might work with a regular NTFS-formatted hard drive, so I pulled my external music backup drive over there and plugged it in and sure enough it worked! Cool! I pulled up an album to listen to. It was one I had not sat through for a year or so, so I relaxed and enjoyed it very much and was impressed by the openness and clarity of the mix and soundstage.

Then on a whim, I decided to play the same album from the music server, mainly to be comparing the nanoAVR DL version of Dirac to the full PC version, expecting the PC version to be a little better somehow. What I heard bothered me more than a little, it just did not sound as clear, and it seemed like it should be at least as good, if not a little better. I went back and forth a few times using different tracks from that album, and, sure enough, the Music Server sound was not as open and clear as that from the Bluray.

I was aware that the level settings in Dirac can be a little different between the two versions, so I was compensating for that with AVR volume while switching back and forth.

Then I got to wondering about the optical signal from the Music Server, which I had not used for awhile since getting 5.1 running via HDMI from the Server. So I switched over to the TOSLINK.

*ZOWIE!* The clarity and openness were back! It had nothing to do with Dirac, it was a noise floor problem running the HDMI from the Server over to the AVR. I verified it by cranking AVR volume to max (being very careful!!!) with streaming but with no music running, and switching from HDMI to HDMI to TOSLINK. With my ear up to the speaker, I could hear hiss using the HDMI from the Server, but not using the HDMI from the Bluray/nanoAVR-DL or the TOSLINK from the Server. The noise floor was high enough using the HDMI from the Server to cloud up the soundstage even though I could hear no noise at the LP even at higher volume settings.

*Measurements:*

I VERY CAREFULLY took these noise floor measurements using the balanced mic input of my audio interface connected to the Main Left speaker output of the Power Amp. I made sure that streaming was taking place for the measurements. After compensating for a smalL gain difference, the noise floor difference is 10 dB. The noise profile is equivalent to white noise. When playing music using the HDMI signal from the Server, the system has 10 dB more noise than when playing music from the Bluray/nanoAVR-DL HDMI input or the Server TOSLINK input.

_measurements to be added shortly..._

*An Experiment:*

Then I created an experiment. Using Reaper, I took a track and made a bunch of versions of it with different amounts of white noise added. I was able to verify that it is possible to perceive the clouding of the soundstage even though I can not hear noise before the music of the track begins. I am going to try to set up a download point where HTS members can download _noisy_ versions of a segment of that track without the amounts of noise identified (a semi-blind test) and a survey to see at what levels HTS members can detect clouding of the soundstage. I am also going to get Tesseract over to see what he hears.

*Definitions:*

All of the signals discussed are digital. The only analog conversion takes place in the AVR. The noise is not being added to the digital signal. The noise is entering the AVR, probably because of a ground loop - the room is not kind to ground loops - depending on what input is selected. I will be digging into the cause further.

*THE LESSON:*

Check your noise floor! With no music running, and with streaming taking place, CAREFULLY crank up your volume level and see what you can hear at the LP and next to your tweeter.

*CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION*
Turn your volume setting down to normal or below before selecting a different source or making ANY change to your AVR settings or anywhere else in your system. Then turn it back up after that change has been made to hear the result.
*CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION - CAUTION
*
If you hear noise at the LP with a normal listening level, your soundstage is seriously compromised.
If you hear noise at the LP with volume at max, or at the tweeter with a normal volume setting, your soundstage is probably somewhat compromised.
If you hear noise at the tweeter with volume at max, your soundstage might be somewhat compromised.

*What to do if you have a problem:*

More investigating and posting to follow...


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## Savjac (Apr 17, 2008)

Good call Craver, and this is not a well thought about phenomena in this hobby. Any noise being introduced into the system, either electrically or mechanically will most likely be detrimental to the listening experience. 

I cannot guess what your noise is as it might be something as easy as a cable or signal from the server through that loop. Using a toslink seems to be the best way to go as it does not involve the possibility of ground loops or other contamination, whilst an HDMI cable should be silent, I too have run into some issues. I would recommend a toslink cable first, then a coax cable then USB and finally hdmi. This is just my opinion of course based upon my system. I use my server with toslink into my DAC and then good interconnects from the DAC to the AVR. Not only is it quiet but I get a pretty substantial amount of dynamic range because it is so quiet. 
Dynamic Range in any given room may be another good discussion.


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## AudiocRaver (Jun 6, 2012)

Thank you for the feedback. There is still much to figure out.

For instance, these differences were observed by simply switching selection of input, not by removing any path that could be a noise path. The?noisy HDMI path was still there, just not selected.

Some careful diagnosis is certainly in order.

I want to be able to play 5.1 from the music server also. So I need to quiet the HDMI path.


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## NBPk402 (Feb 21, 2012)

I am always wondering if I am losing any info from the noise floor...subscribed to see what you turn up. :T:T


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## Savjac (Apr 17, 2008)

AudiocRaver said:


> Thank you for the feedback. There is still much to figure out.
> 
> For instance, these differences were observed by simply switching selection of input, not by removing any path that could be a noise path. The?noisy HDMI path was still there, just not selected.
> 
> ...


Understood.
I am curious if you had changed out the hdmi cable you are using with another one just as a test. There are indeed noisy cables by way of the connectors on the ends amongst other things. Also can you try other hdmi inputs on your AVR ? Believe it or not I have one set of rca inputs on my Denon that have some issue in that they are not quite as clean as the others. I have to not use those inputs and yes I should have it fixed but the last time I sent it in it took 8 weeks to get it back so I just use another of the plentiful inputs. 

I am also thinking that multi channel can be passed into the AVR via coax of toslink if the system is set up that way, are you able to do that ? Of course these options cannot pass video but it sounds like you wish to pass audio only. 
It seems that sometimes electronics just do not always talk well to one another depending on how they are hooked together in a system. I was using two subwoofers once and had only one subwoofer out jack on the back of the Pioneer receiver. So thought I, I can just put a "Y" connector on the back of the AVR and voila, I can now send a signal to two subwoofers equally. Nope did not work. Somehow the signals got tossed back and forth, not sure why or how, and the sound of the entire system got skewed to the point wherein one channel was about 15db lower than the other. This is a funny hobby. 

It is good you are experimenting with these issues in the best way possible, the free way for now before swapping out other components.


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## Tonto (Jun 30, 2007)

I really do appreciate all your efforts on our hobby, all the littel details you find that help us to make our systems preform to their fullest. Thanks Wayne! :clap:


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## chashint (Jan 12, 2011)

Good opening of the thread, you have already done a lot and your process is described well. What are the audio output settings for the various source machines?


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## Talley (Dec 8, 2010)

i have some noise/buzz... nothing playing amp on and preamp on... its making noise. I been lazy and haven't messed with it but need to work on it.

part of the issue is I can't have my amp grounded or it really does the ground loop buzz so I had to disconnect it. What I'm gonna have to try out is the rca->xlr bypassing the ground to see if that eliminates the cross talk.

It sucks too because I spent alot of time and energy running 10 dedicated circuits and ran all isolated grounds and have a dedicated ground bus in the panel that is isolated and a 2/0 cable runs down outside to 3 ground rods spaced in a triangle format 10' spacing.

I need to not be lazy and fix it. I'm also going to add some balanced transformers to the system.


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## Talley (Dec 8, 2010)

well worked on my system and ended sleeving the bare ground cables in my outlet box to further isolate the cables... I did find the buzz culprit and it was my Krell not having the xlr shorting pins not installed. I made some out of some 10g solid wire and that significantly lowered the buzz/hiss I was experiencing. 

I also moved my center channel off the stand it was on and moved my rack to absolute center and put my center channel on top the rack. By doing this I had to move the amp to the left side and the XMC to the right side and so I took alot of time isolating all the wires and keeping as much space as I could between them. I also reconnected the ground wire to the amp circuit and I'm happy to report that my system is "essentially silent" With all the equipment on with nothing playing and/or the music on pause and the volume at near silent, -20 and at 0 and also +12 I am experience nothing audible at the LP and nothing audible 6" away from the speakers. I do hear a slight... very faint hiss from the tweeter when my ear comes to within 1" of the tweeter.

This is a significant change from my previous and since I moved some things around I need to re-run Dirac and do some listening. I'll report back what I find.


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## AudiocRaver (Jun 6, 2012)

That was a lot of work. We will be very interested in hearing what you discover in your listening tests. Good diagnostic work by the way. Those things are not always easy to find.


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## Talley (Dec 8, 2010)

AudiocRaver said:


> That was a lot of work. We will be very interested in hearing what you discover in your listening tests. Good diagnostic work by the way. Those things are not always easy to find.


3hrs total w/ troubleshooting. Thanks it was.

I basically can say that my system is silent... but man you really gotta stick your ear right next to the tweeter and barely hear a hiss... at first I couldn't hear it but the kids where laughing/playing in the adjacent room... when the house was quiet for a brief rare moment I checked again and its very faint.

at this point I'm not sure what to do to 100% eliminate it but it's not like I run the system at max volume with nothing playing and have my ear less than 1" away from the tweeter anyway.

...it felt like playing russian roulette doing this too lol...


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## AudiocRaver (Jun 6, 2012)

I know what you mean.

While I was taking measurements with my mic input connected to my speaker output, I felt exactly the same way.

If you can barely hear his with your ear next to the tweeter and the volume all the way up, you are way into the safe zone and can probably get it no better no matter what you do. That is about where my system is over the optical input, and that is as good as it seems to need to be for ultimate sonic performance.

From what I can tell with my system, if you can hear it at the LP with the volume all the way up, or if you can hear it at the speaker with volume at normal level, you need to do some work. In your case, you are way beyond that. It sounds like you started out being able to hear stuff at the LP at normal volume, which means serious problem.


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## Talley (Dec 8, 2010)

I did have a problem... I could hear it at normal listening levels at the LP. THD was sitting around 1-2% all the way throughout the audible range. It wasn't that bad w/ the Denon but since the XMC it was there but again laziness is my weakness. I'll be sure to retest this and see if I can capture the difference on the REW chart.

This thread motivated me to get off my butt and fix it. Thanks!


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## Talley (Dec 8, 2010)

Wow... I've only listened to a few tracks but like you said the clarity but more so the openness has really improved dramatically. The soundstage "space" has opened up like my walls and ceiling are 30 feet away. The sound seems to have grown around the sides of the wall but the sound is more centered. It's a very weird change. The instruments show more pinpoint location and have appeared to of moved in slightly but the space or the sound of the room they recorded in has really opened up and grew around my room.

It's definately a change for the plus but wow... I can't wait to burn in some more time this week. This was running DIRECT mode because I still need to re-run Dirac.


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## AudiocRaver (Jun 6, 2012)

Excellent. Thank you for letting us know your results. It makes you wonder how systems there are out there that could sound a whole lot better with just a little diagnostic work and a few minor changes.

It is a weird change. Kind of hard to describe the difference until you have heard it. Openness, depth of the darkness between sound images, contrast, the sound that is there seems to stand out more ..


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## arkiedan (Oct 20, 2013)

My system seems to hiss all the time! But wait!! That might just be my tinnitis I'm hearing! lddude:


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## willis7469 (Jan 31, 2014)

AudiocRaver said:


> Excellent. Thank you for letting us know your results. It makes you wonder how systems there are out there that could sound a whole lot better with just a little diagnostic work and a few minor changes.
> .


 since you started this thread, I've become certain that my system is one that could benefit. Especially since I've added the Yamaha amp. Somewhere since then, I've picked up a hiss. I can't hear it past about a foot, and the only thing I can think to do is drop the gain on the amp and raise the trim in the avr to compensate. I'll check tomorrow to see what happens without a signal with the volume up. The Yamaha has added a lot(of little qualities) and I'd like to wring it out the rest of the way. I appreciate your cramazing(yep, crazy/amazing) dedication. I can't help but think of Tom Noussaine. 





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## AudiocRaver (Jun 6, 2012)

willis7469: if you can hear the hiss at one foot with the volume at a normal listening well, then you have a problem. If you can hear the hiss only with the volume turned all the way to max, then you might be OK.


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## willis7469 (Jan 31, 2014)

Thanks Wayne. I figured you would say that! I just did a little impromptu check at lunch. The distance is more like 6 inches. The sound is a mix of hiss/hum. The sound doesn't change output no matter how loud or soft the volume. That makes me think 60hz hum. I have 4 dedicated 20a circuits to the wall for the purpose of powering my gear, but everything is plugged into an APC h10. Any ideas? So far, I'm loving this amp. 


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## Talley (Dec 8, 2010)

willis7469 said:


> Thanks Wayne. I figured you would say that! I just did a little impromptu check at lunch. The distance is more like 6 inches. The sound is a mix of hiss/hum. The sound doesn't change output no matter how loud or soft the volume. That makes me think 60hz hum. I have 4 dedicated 20a circuits to the wall for the purpose of powering my gear, but everything is plugged into an APC h10. Any ideas? So far, I'm loving this amp.
> 
> 
> Sent from my iPhone using Tapatalk


ground loops will sound like this: 




Handling those issues should be done like this: 




Hiss comes from other sources... high frequency noise introduced on the line by a number of any unknown sources. Truth be told... try it without the UPS. I've read that UPS equipment throws alot of high frequency noise onto the a/c lines. might want to take that out and retry... report your findings back to us.

moving to balanced xlr connections and using balanced isolation transformers are ways to further eliminating the noise.


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## AudiocRaver (Jun 6, 2012)

willis7469 said:


> Thanks Wayne. I figured you would say that! I just did a little impromptu check at lunch. The distance is more like 6 inches. The sound is a mix of hiss/hum. The sound doesn't change output no matter how loud or soft the volume. That makes me think 60hz hum. I have 4 dedicated 20a circuits to the wall for the purpose of powering my gear, but everything is plugged into an APC h10. Any ideas? So far, I'm loving this amp.
> 
> Sent from my iPhone using Tapatalk


Interesting that the noise level does not change with your volume setting. Do you have an external power amp? The noise appears to be entering the system after the volume control of your Yamaha You can try a ground lifter plug on it also to see if that helps. I agree with Tally to try it without the ups also. I had to try a couple to end up with a very quiet model that puts out a pure sine wave when it fires up. And is very quiet. When it comes to hum and noise, the solution can seem mysterious and nonsensical sometimes.


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## willis7469 (Jan 31, 2014)

Yes Wayne. It is an external amp. It's fed by an onkyo txnr-808. The amp is a pro model p2500s. I tried going straight to the wall and it didn't change a thing. Also, nothing changes by altering the gain(or should I say attenuation) knobs on the amp. I used 1/4" to TS connectors. I wonder if it's there?


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## NBPk402 (Feb 21, 2012)

willis7469 said:


> Yes Wayne. It is an external amp. It's fed by an onkyo txnr-808. The amp is a pro model p2500s. I tried going straight to the wall and it didn't change a thing. Also, nothing changes by altering the gain(or should I say attenuation) knobs on the amp. I used 1/4" to TS connectors. I wonder if it's there?
> 
> 
> Sent from my iPhone using Tapatalk


Strange... my horns are 112db efficiency, and mine were dead silent with my P2500s amps when i had them. My P7000s amp is dead quiet with the Danley DTS-10 too.


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## willis7469 (Jan 31, 2014)

ellisr63 said:


> Strange... my horns are 112db efficiency, and mine were dead silent with my P2500s amps when i had them. My P7000s amp is dead quiet with the Danley DTS-10 too.



I remember you saying that. That's partly why I was so surprised to hear noise. It doesn't change amplitude so I feel like it's not in the pre stage. Puzzling, and frustrating. Btw Ron, no regrets buying this amp. Despite the noise, it has still changed my space for the better. That's also why I need to get a handle on this. 


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## Talley (Dec 8, 2010)

willis7469 said:


> I remember you saying that. That's partly why I was so surprised to hear noise. It doesn't change amplitude so I feel like it's not in the pre stage. Puzzling, and frustrating. Btw Ron, no regrets buying this amp. Despite the noise, it has still changed my space for the better. That's also why I need to get a handle on this.
> 
> 
> Sent from my iPhone using Tapatalk


It could just be noise on the AC lines coming from all sorts of who knows where. You may want to try moving all 4 of your dedicated 20 amp circuits to the same leg on the panel if it's not done so already.

Like mentioned this can come from anywhere.... even the neighbors house since all residential shares feeds.


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## AudiocRaver (Jun 6, 2012)

willis7469 said:


> I remember you saying that. That's partly why I was so surprised to hear noise. It doesn't change amplitude so I feel like it's not in the pre stage. Puzzling, and frustrating. Btw Ron, no regrets buying this amp. Despite the noise, it has still changed my space for the better. That's also why I need to get a handle on this.
> 
> 
> Sent from my iPhone using Tapatalk


I just reported in this thread that the Furman PST-8D power conditioner that I just got has solved (still have to measure to confirm) the HDMI noise problem from the music server. Your problem might just be noise from one component getting into another through power. Furman conditioners are good at eliminating HF and RF noise problems.

Also, don't forget to try a ground isolation plug.


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## Talley (Dec 8, 2010)

AudiocRaver said:


> I just reported in this thread that the Furman PST-8D power conditioner that I just got has solved (still have to measure to confirm) the HDMI noise problem from the music server. Your problem might just be noise from one component getting into another through power. Furman conditioners are good at eliminating HF and RF noise problems.
> 
> Also, don't forget to try a ground isolation plug.


Please do not defeat the ground of the equipment or recommend it. It's a safety hazard.


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## AudiocRaver (Jun 6, 2012)

Talley said:


> Please do not defeat the ground of the equipment or recommend it. It's a safety hazard.


As Talley says, it can create a safety hazard. If you try it, do so with great care. If you do not know how to approach it safely, do not try it. All due respect, I would not suggest it if I thought it was a real great risk. Ground loops are a common cause of noise in audio systems, and isolating or lifting grounds is a common way of diagnosing and trying to solve such problems. A lot of modern equipment does not even have the third wire ground, by design, to help prevent ground loop problems.

A good power conditioner like the Furman, is probably a better solution all around , in that it breaks the loop effectively in the frequency range concerned with filtering, all with perfect safety.


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## Talley (Dec 8, 2010)

AudiocRaver said:


> As Talley says, it can create a safety hazard. If you try it, do so with great care. If you do not know how to approach it safely, do not try it. All due respect, I would not suggest it if I thought it was a real great risk. Ground loops are a common cause of noise in audio systems, and isolating or lifting grounds is a common way of diagnosing and trying to solve such problems. A lot of modern equipment does not even have the third wire ground, by design, to help prevent ground loop problems.
> 
> A good power conditioner like the Furman, is probably a better solution all around , in that it breaks the loop effectively in the frequency range concerned with filtering, all with perfect safety.


I've been doing alot of research on the ground loops and general noise. I am a master electrician for Texas, went through 5yrs of training... and have 15years of experience. I'm extremely educated in AC circutry and also work in the Petrochemical industry for the past 10yrs for an instrumentation company where we install automated DCS systems typically with 24v systems dealing with milli-amp controls. Isolated grounds, reference grounding, shielding, etc.... over the years I've grown to see alot in the industry. My background is commercial/residential service work, new construction commercial and again past 10 years petrochemical. I by no means am any expert but I do consider myself to be successful in my career and very knowledgable. One thing that I must admit is I am by no means any expert on A/V equipment INTERNAL circuitry. I am researching because I want to become a good source of information so I can assist others on this site with any issues. I am however not an electrical engineer so please keep that in mind. 

With that being said one of the best articles I can recommend anyone reading is this one:

http://www.surgex.com/pdf/PowerGround.pdf

most all noise.... can be eliminated through proper grounding. Some devices only promote. UPS equipment being one of them. I've designed my power system feeding my equipment to be that of an isolated ground type. It works... when done right. Noise you are hearing are without a doubt caused by something... and typically it's the noise on shields and/or high frequency noise on the a/c line being present because the grounding system is not up to par to dissipate this.

People think I'm nuts for my power system... but it works. Here is my dedicated panel showing the isolated ground bar.... where I have dedicated grounds going to each receptacle in my system traveling back to a main bus. This bus is isolated from earth ground in the panel using isolation mounting blocks and this ground bar is connected to the ground rod outside where the earth ground is also connected. My ground rod(s) are the main common point and this connection is IN THE GROUND. I have both the isolated ground wire from the busbar and the common earth ground wire from the panel attach to a single ground rod that is kept very short and uses a large #2 cable. Then I have TWO more ground rods installed forming a triangle that are spaced 10' apart and those are connected together using a 2/0 cable.

I do not use surge protection and do not use UPS equipment.


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## AudiocRaver (Jun 6, 2012)

Talley said:


> ...most all noise.... can be eliminated through proper grounding.


I completely agree. And the grounding system you describe sounds exemplary, and it is always better to keep noise low through using such practices, but I am also confident that very few listening or home theater rooms have a grounding system like the one you describe. Just like most rooms do not have ideal acoustical symmetry or ideal acoustical treatment. In the case of grounding, it promotes a quiet system while being safer than lifting grounds, another good reason to do it that way, but even so there are probably only a few who would go to the trouble.

It is a reality in our hobby that few users have the luxury of having ideal _anything_ in their systems. Most start from a _best they can do on a budget_ perspective and have to do some bandaid work from there. But your description of an ideal grounding system is much appreciated and is useful for all to keep in mind as the ideal and as a goal when the opportunity arises.



> Some devices only promote. UPS equipment being one of them. I've designed my power system feeding my equipment to be that of an isolated ground type. It works... when done right. Noise you are hearing are without a doubt caused by something... and typically it's the noise on shields and/or high frequency noise on the a/c line being present because the grounding system is not up to par to dissipate this.


I would not say that UPS equipment _only promotes,_ implying that there is only downside and no upside. UPS in my case is for my Windows desktop machines - I have two - and helps prevent operating and file system corruption in the event of power outage. A well-designed UPS can be fairly quiet in terms of HF noise generation. Mine is used only for those two computers, the rest of my audio equipment runs on the same outlets/circuit but not off of the UPS.

I readily agree that _typical_ UPS equipment can be a source of noise, and might not even keep a computer from shutting down the way it is supposed to. Mine is designed to provide a pure, low-distortion sine wave output when the input power disappears, and I have tested it to be effective in running my systems safely.

Another point not yet mentioned, that I learned the hard way (a long, painful story) is that all of the equipment in an audio and/or computer system should run off of the same power phase. Most homes are supplied from a 240 V two-phase transformer. So there are two phases available in a house at its outlets. Without a voltmeter, one cannot tell if two sets of outlets, even in the same room, are on the same phase or on the opposing phases. I always check with a voltmeter. Measuring from hot to hot will show the 240 V value if two sets of outlets are on opposing phases. This can cause noise and even equipment damage where sensitive inputs in equipment on one phase are driven from outputs on the opposing phase. Some will argue that it should not be a problem, I can testify from first hand experience that it can be a cause of equipment damage.

Talley, I appreciate your post and your comments and perspectives, and I am not arguing with anything you have said - except on the UPS point a little - simply clarifying a few points.


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## Talley (Dec 8, 2010)

AudiocRaver said:


> I completely agree. And the grounding system you describe sounds exemplary, and it is always better to keep noise low through using such practices, but I am also confident that very few listening or home theater rooms have a grounding system like the one you describe. Just like most rooms do not have ideal acoustical symmetry or ideal acoustical treatment. In the case of grounding, it promotes a quiet system while being safer than lifting grounds, another good reason to do it that way, but even so there are probably only a few who would go to the trouble.
> 
> It is a reality in our hobby that few users have the luxury of having ideal _anything_ in their systems. Most start from a _best they can do on a budget_ perspective and have to do some bandaid work from there. But your description of an ideal grounding system is much appreciated and is useful for all to keep in mind as the ideal and as a goal when the opportunity arises.
> 
> ...


Thank you and note that your comments are 100% accurate. I should retract my statement and say "Typical" UPS equipment so there are good equipment out there just research before you buy and I do agree that for a computer it's important. I have a APC UPS on my computer only to keep power flickers from turning the computer off.

I recently found out about the phasing myself.... not thinking about it previously. Good thing for me all I need to do is move a few breakers around to complete this. 

Good point and forgot about that, literally read up on it a few days ago late one night. Haven't tried it yet but will do that TONIGHT. I'll report back if that very faint hiss that is on my system within 1/2" is completely removed. Not sure what will happen when I move everything to the same phase yet or not to my system.

EDIT: I actually commented on this on post #25 on this thread last night http://www.hometheatershack.com/for...ems-noise-floor-low-enough-3.html#post1350393


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## AudiocRaver (Jun 6, 2012)

Talley said:


> EDIT: I actually commented on this on post #25 on this thread last night http://www.hometheatershack.com/for...ems-noise-floor-low-enough-3.html#post1350393


So you did, and I missed that. Very few seem to know about that, or at least say so. Thanks again for your insights.


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## willis7469 (Jan 31, 2014)

Thanks for the tips guys. Just for clarity, my APC is not a ups(computer has one though). I will look up specs for its filtering capabilities. There is plenty of food for thought here, and I will start with something not yet mentioned. I am going to unbraid the snake pit behind my rack and organize, and check all my connections. This is free! I did look up the furman and the extra hundred bucks will definitely go to my kids Christmas fund first. 
Side note, my AC isn't as dedicated as Talleys, but I did pull 4 home runs to where my rack is and separately grounded each one to earth. Talleys point of sharing bus bars makes sense but I don't know when I'll open the service panel up(in a hole). This system was silent as a stone before adding the Yamaha amp so I hope to find something when I start sorting cable. Thanks again. Best forum ever!


Sent from my iPhone using Tapatalk


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## Talley (Dec 8, 2010)

I'm still learning and trying to grasp all the interconnect/shielding/grounding stuff now. I have to lean on alot of pro audio experts advice and use my personal electrical background and try to make sense of it all.

One thing is for sure.... without a doubt a ground issue can be the biggest pain to correct.


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## NBPk402 (Feb 21, 2012)

willis7469 said:


> Thanks for the tips guys. Just for clarity, my APC is not a ups(computer has one though). I will look up specs for its filtering capabilities. There is plenty of food for thought here, and I will start with something not yet mentioned. I am going to unbraid the snake pit behind my rack and organize, and check all my connections. This is free! I did look up the furman and the extra hundred bucks will definitely go to my kids Christmas fund first.
> Side note, my AC isn't as dedicated as Talleys, but I did pull 4 home runs to where my rack is and separately grounded each one to earth. Talleys point of sharing bus bars makes sense but I don't know when I'll open the service panel up(in a hole). This system was silent as a stone before adding the Yamaha amp so I hope to find something when I start sorting cable. Thanks again. Best forum ever!
> 
> 
> Sent from my iPhone using Tapatalk


I have cleaned up rats nest of wiring in the past, and eliminated ground loops. That might be all you need. :T:T


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## willis7469 (Jan 31, 2014)

Fingers crossed! Wires uncrossed!


Sent from my iPhone using Tapatalk


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## Talley (Dec 8, 2010)

I moved all my circuits to the same phase and it introduced a very slight buzz... mainly from midrange/tweeter but it's very very faint. I literally press my ear to the tweeter to hear it. it's definately a buzz where as before was a faint hiss and not detectable in the midrange.

i mean I have volume set to max... and my ear to the tweeter pressed against it. with a disc in the player on pause.

shoot me if it ever decided to play at that moment eeek.


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## Savjac (Apr 17, 2008)

As everyone has mentioned, noise comes from many sources and for many reasons. If you can turn the amp up and down without an increase in noise volume then the point of the noise is before the amp. If you are using a computer or music server the noise could come from there and would most probably be a light buzz in the system. Sometimes cables make a difference, and by that I mean interconnects. I have been listening to some different interconnects recently and every now and then I would get a weird buzz. I took cables out of the system and replaced them with tried and true cables until I found the bad ones. 

If anyone wants to try an experiment this one is cool. Much of the equipment we use does not have a ground plug but merely a double bump on one of the prongs of our power cable. A manufacturer once told me at an audio show in Chicago that when these electronics are manufactured, there is only a 50/50 chance that the line assemblers will get the negative portion of the power cord soldered to the right pin in the electronics. He went on to tell me how to check. You put a cheater plug ( And yes this works with 3 pronged plugs as well ) on the original make end of the chord and plug it into the wall. Then take your multi meter and set it low and take one end of the meter cable and touch the ground of the wall socket and the other end of the meter cable touch a metal component of your equipment. Write down the value. Now turn off the equipment and change the orientation of your cheater plug in the wall outlet and do the same thing with your multi meter and write down the values. Which ever of the 2 values that is lowest would indicate which way the negative side of the power cord should reside in the wall outlet. 

By the way, It works.


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## AudiocRaver (Jun 6, 2012)

ellisr63 said:


> I have cleaned up rats nest of wiring in the past, and eliminated ground loops. That might be all you need. :T:T


Agree, that is the best place to start.


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## AudiocRaver (Jun 6, 2012)

Savjac said:


> If anyone wants to try an experiment this one is cool. Much of the equipment we use does not have a ground plug but merely a double bump on one of the prongs of our power cable. A manufacturer once told me at an audio show in Chicago that when these electronics are manufactured, there is only a 50/50 chance that the line assemblers will get the negative portion of the power cord soldered to the right pin in the electronics. He went on to tell me how to check. You put a cheater plug ( And yes this works with 3 pronged plugs as well ) on the original make end of the chord and plug it into the wall. Then take your multi meter and set it low and take one end of the meter cable and touch the ground of the wall socket and the other end of the meter cable touch a metal component of your equipment. Write down the value. Now turn off the equipment and change the orientation of your cheater plug in the wall outlet and do the same thing with your multi meter and write down the values. Which ever of the 2 values that is lowest would indicate which way the negative side of the power cord should reside in the wall outlet.
> 
> By the way, It works.


Good suggestion.


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## AudiocRaver (Jun 6, 2012)

Savjac said:


> If you can turn the amp up and down without an increase in noise volume then the point of the noise is before the amp.


Don't you mean after the amp?


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## Savjac (Apr 17, 2008)

Good question Craver, but I was thinking that the amp is the last item in the chain before the speakers, and, I was considering a pro amp which has volume controls. With everything in the system off except the amp, listen and if it is quiet, then the problem most probably comes from something before the amplifier. 

Does that make sense or did I still get it wrong ??


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## willis7469 (Jan 31, 2014)

Hi jack, I follow you. I can only speak for my personal situation. What I find odd is that by changing volume on the avr OR the amp, the sound stays the same. I won't be able to dig into it for awhile but when i do, I'm going to be very thorough, as tending to the snake pit has been on my list for awhile. 


Sent from my iPhone using Tapatalk


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## albe (Nov 25, 2015)

I spent the afternoon in NYC yesterday, went to LUPA for lunch then headed over to Stereo Exchange to a listening session with Sandy Gross from Golden Ear...this after giving blood to Red Cross in the morning, needless to say I was tired when I got home last night.

This morning I decided to listen to my noise floor... :dontknow:
I DID hear hiss with nothing playing (at MAX V within 1") so on advice from this thread, I removed my Tripplite UPS and noticed all the hiss (at MAX V within 1") had moved out...

Guess what, I did hear a very faint 60 cycle hum AFTER the hiss was removed...(which I DID NOT hear with the hiss) I grounded my Monster power to my Tripplite NON-UPS 1800AC line conditioner to the Green ground in the outlet and now THAT is eliminated.

Thank you all  for your contributions to great little tweak I would have never ventured if I didn't read it here!


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## AudiocRaver (Jun 6, 2012)

Savjac said:


> With everything in the system off except the amp, listen and if it is quiet, then the problem most probably comes from something before the amplifier.
> 
> Does that make sense or did I still get it wrong ??


That makes sense.

With the entire system running, if the noise level goes up and down with the volume control, the noise is entering the system before the volume control.:dontknow::bigsmile: It could be getting in

with the signal on an input
via the power or grounding and entering the AVR's circuitry before the volume control
via magic (not really, just seeing if you're listening)


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## AudiocRaver (Jun 6, 2012)

albe said:


> I spent the afternoon in NYC yesterday, went to LUPA for lunch then headed over to Stereo Exchange to a listening session with Sandy Gross from Golden Ear...this after giving blood to Red Cross in the morning, needless to say I was tired when I got home last night.
> 
> This morning I decided to listen to my noise floor... :dontknow:
> I DID hear hiss with nothing playing (at MAX V within 1") so on advice from this thread, I removed my Tripplite UPS and noticed all the hiss (at MAX V within 1") had moved out...
> ...


I am more than a little embarrassed how long I have put up with noises and buzzes like that. Way to go getting it fixed!


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## Savjac (Apr 17, 2008)

AudiocRaver said:


> That makes sense.
> 
> With the entire system running, if the noise level goes up and down with the volume control, the noise is entering the system before the volume control.:dontknow::bigsmile: It could be getting in
> 
> ...


Yes Mr. AC I am listening, but I think you may not be all that far off base. I am not an engineer nor did i take any electrical class back in school so electricity, electronics and computers are indeed magic to me. I am the hands on guy so I understand mechanical but those other things provide me with no clues. Your chart early on gave me nightmares LOLOL


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## rab-byte (Feb 1, 2011)

Savjac said:


> If anyone wants to try an experiment this one is cool. Much of the equipment we use does not have a ground plug but merely a double bump on one of the prongs of our power cable. A manufacturer once told me at an audio show in Chicago that when these electronics are manufactured, there is only a 50/50 chance that the line assemblers will get the negative portion of the power cord soldered to the right pin in the electronics. He went on to tell me how to check. You put a cheater plug ( And yes this works with 3 pronged plugs as well ) on the original make end of the chord and plug it into the wall. Then take your multi meter and set it low and take one end of the meter cable and touch the ground of the wall socket and the other end of the meter cable touch a metal component of your equipment. Write down the value. Now turn off the equipment and change the orientation of your cheater plug in the wall outlet and do the same thing with your multi meter and write down the values. Which ever of the 2 values that is lowest would indicate which way the negative side of the power cord should reside in the wall outlet.
> By the way, It works.


I really don't understand how that would work with a 2 prong plug?!? A 3 prong I could see being miswired (I've seen it plenty in clients' homes) but A/C is delivering 60v on each leg every 1/60 of a second ([email protected]). That means half the time your negative poll is switched. This works because virtually all electronics use DC power internally. So inside your component there is an AC to DC converter. This is usually two parts a transformer is used to step down the voltage:
https://en.m.wikipedia.org/wiki/Transformer
And an AC/DC converter:
https://en.m.wikipedia.org/wiki/Rectifier
So regardless of what leg is plugged into what leg of a 2 prong it should be the same.


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## AudiocRaver (Jun 6, 2012)

rab-byte said:


> I really don't understand how that would work with a 2 prong plug?!? A 3 prong I could see being miswired (I've seen it plenty in clients' homes) but A/C is delivering 60v on each leg every 1/60 of a second ([email protected]). That means half the time your negative poll is switched. This works because virtually all electronics use DC power internally. So inside your component there is an AC to DC converter. This is usually two parts a transformer is used to step down the voltage:
> https://en.m.wikipedia.org/wiki/Transformer
> And an AC/DC converter:
> https://en.m.wikipedia.org/wiki/Rectifier
> So regardless of what leg is plugged into what leg of a 2 prong it should be the same.


Not quite true. With a 120V two-prong outlet, one prong goes to neutral, which ends up tied to ground back at your service panel or somewhere back there (Talley, help!). The other prong, "hot," goes to 120V. If there is a third prong, the ground, it goes directly to ground at your service panel for safety.

After passing through the power transformer of a typical piece of audio gear with a linear power supply, the rectified and filtered result is DC, as you say. The transformer secondary may or may not be balanced, depending on the design of that piece of gear. On the 120V primary of a power transformer, one lead will go to ground and the other to "hot," as discussed. The incoming AC, at the socket, is not balanced at a 120V outlet, as you suggested. At a 120V outlet, where only one phase of the incoming 240V power is wired, the power will appear unbalanced relative to ground. The 240V power coming into your home is balanced, but you only see both phases of that power in one outlet at a 240V dryer or stove or air conditioner outlet.

With a piece of gear that has a two-prong plug, depending exactly how it is wired inside, the test Savjac described should work.

Some enthusiasts defy all of these rules with special balanced transformers and power distribution, but this is in defiance of code and is rare.


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## rab-byte (Feb 1, 2011)

So a two prong is only getting voltage half the time?!?


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## Talley (Dec 8, 2010)

AudiocRaver said:


> Not quite true. With a 120V two-prong outlet, one prong goes to neutral, which ends up tied to ground back at your service panel or somewhere back there (Talley, help!). The other prong, "hot," goes to 120V. If there is a third prong, the ground, it goes directly to ground at your service panel for safety.
> 
> After passing through the power transformer of a typical piece of audio gear with a linear power supply, the rectified and filtered result is DC, as you say. The transformer secondary may or may not be balanced, depending on the design of that piece of gear. On the 120V primary of a power transformer, one lead will go to ground and the other to "hot," as discussed. The incoming AC, at the socket, is not balanced at a 120V outlet, as you suggested. At a 120V outlet, where only one phase of the incoming 240V power is wired, the power will appear unbalanced relative to ground. The 240V power coming into your home is balanced, but you only see both phases of that power in one outlet at a 240V dryer or stove or air conditioner outlet.
> 
> ...


Let me say what I know. your 120V will have one lead hot, one lead neutral and one ground.... even though your neutral is grounded (done at the panel in homes) it is not considered a ground. grounded conductor = neutral, grounding conductor = ground. Also your 240V power at your house is not balanced. The phases are 120 degrees apart. Balanced = 180degrees out of phase from each leg and you get that by grounding the center tap on the secondary. This provides 60V on one side and 60V on other side. 

balanced is not a defiance of code but yes it is rare. A requirement for moving to balanced is the need for GFCI protection to remain "in code". 

Some equipment like many receivers and bluray players will only use two prong outlets because they are considered to be double insulated and they float the ground. Double insulated appliances are legal and I believe some are done in the audio world to minimize ground loops and the problem exists when you have a pre-amp that is two prong and an amp that is three prong and using RCA connectors because the negative is bonded at some point to the ground in the pre-amp thus causing a ground loop. Balanced connectors helps this but simply grounding all the equipment to a common ground also does this as well.


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## AudiocRaver (Jun 6, 2012)

Talley said:


> Let me say what I know. your 120V will have one lead hot, one lead neutral and one ground.... even though your neutral is grounded (done at the panel in homes) it is not considered a ground. grounded conductor = neutral, grounding conductor = ground. Also your 240V power at your house is not balanced. The phases are 120 degrees apart. Balanced = 180degrees out of phase from each leg and you get that by grounding the center tap on the secondary. This provides 60V on one side and 60V on other side.
> 
> balanced is not a defiance of code but yes it is rare. A requirement for moving to balanced is the need for GFCI protection to remain "in code".
> 
> Some equipment like many receivers and bluray players will only use two prong outlets because they are considered to be double insulated and they float the ground. Double insulated appliances are legal and I believe some are done in the audio world to minimize ground loops and the problem exists when you have a pre-amp that is two prong and an amp that is three prong and using RCA connectors because the negative is bonded at some point to the ground in the pre-amp thus causing a ground loop. Balanced connectors helps this but simply grounding all the equipment to a common ground also does this as well.


Excellent summary, thanks, Talley. I had completely forgotten about the 120° phase angle on the two 120V phases.

Question: If measuring between those two phases, wouldn't you measure something like 180V between them, a value greater than 120V but less than 240V ??


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## AudiocRaver (Jun 6, 2012)

rab-byte said:


> So a two prong is only getting voltage half the time?!?


A two prong is getting AC voltage all the time, but it is all on the "hot" lead relative to ground. That voltage is a sine wave, 120V RMS. Each peak gets to 170V peak in each direction relative to ground. In a piece of audio gear with a typical center-tap-secondary and full-wave rectifier power supply, each side of the DC is getting recharged 120 times per second.


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## NBPk402 (Feb 21, 2012)

Is the 3rd wire different once it exits the house... I ask this because last year we had over 200V going to all our outlets in the house. PG&E came out to our house, and found that one of the wires (from the transformer on the pole) had a bad connection, and they said the 3rd wire was what controlled the voltage. They said that since the wire had a bad connection it allowed full voltage to go to our house. We lost some thermostats, and a low voltage transformer in the deal.


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## Talley (Dec 8, 2010)

AudiocRaver said:


> Excellent summary, thanks, Talley. I had completely forgotten about the 120° phase angle on the two 120V phases.
> 
> Question: If measuring between those two phases, wouldn't you measure something like 180V between them, a value greater than 120V but less than 240V ??


I can't remember off the top of my head but it's 120v RMS... peak to peak is around 150v. Remember it cycles at 60hz meaning 60 times a second there is ZERO voltage... If you were lightning quick you could touch it and not get shocked but chances are 100.1% your not so your gonna get zapped lol.

All sorts of systems out there... delta high leg, delta corner ground is one that I still don't understand and is dangerous and yes I have encountered it although it's seldom used. wye connected (star) so many variables exist.


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## Talley (Dec 8, 2010)

ellisr63 said:


> Is the 3rd wire different once it exits the house... I ask this because last year we had over 200V going to all our outlets in the house. PG&E came out to our house, and found that one of the wires (from the transformer on the pole) had a bad connection, and they said the 3rd wire was what controlled the voltage. They said that since the wire had a bad connection it allowed full voltage to go to our house. We lost some thermostats, and a low voltage transformer in the deal.



sounds funny and really not sure. could of been a number of things. losing a neutral or having a bad connection can fluctuate voltage but man it really depends... alot of utilities will operate different voltages albeit within 5% of eachother. I still find it crazy that you'll have 6-10 powerhouses spread across an entire state and they all work together because they are phase aligned to provide the overall power sharing.

I have to retract my previous statement. Single phase in a home the 240V is a balanced IF derived from a single phase 7200v leg on a 13kv 3phase system. If two transformers are used in deriving 240v from a 13kv system then you'll have 240v that is 120 degrees out of phase. It can depend on where your at (city or urban). TYPICALLY your balanced 240V single phase. Had a discussion with a fellow friend who reminded me that. I haven't been in the residential sector in over 10 years and deal strictly w/ 3 phase now but you can still find residential from 3 phase in more urban areas.. or if your underground too you can 3 phase. Just really all depends on your area.


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## FargateOne (Mar 3, 2015)

Talley said:


> Wow... I've only listened to a few tracks but like you said the clarity but more so the openness has really improved dramatically. (...) but the sound is more centered. It's a very weird change. The instruments show more pinpoint location and have appeared to of moved in slightly but the space or the sound of the room they recorded in has really opened up and grew around my room.
> 
> It's definately a change for the plus but wow(...).





AudiocRaver said:


> (...) It makes you wonder how systems there are out there that could sound a whole lot better with just a little diagnostic work and a few minor changes.
> 
> It is a weird change. Kind of hard to describe the difference until you have heard it. Openness, depth of the darkness between sound images, contrast, the sound that is there seems to stand out more ..


All those comments are thrue.

I got the same impression since yesterday when I finally get rid of a hum that I did even not know that it was there before I cranked up the main volume with the bd player in multi-channel mode and put it to pause. My set-top box is connected via hdmi to the player not the receiver. The only link to the receiver is hdmi cable from the player and hdmi to the TV. Disconnecting the coax cable from the set-top box made the hum to disappear. I first discovered that the cable was not properly grounded outside the house. After having corrected this, the hum was still there! Finally I changed the hdmi cable between the set-top box (cable decoder) and the player. The hum at 60hz was lowered by more than 90%. I also connected a coax cable between the set-top box and the receiver = hum killed and what a difference in the sound and SS&I !

I must to say that I was confused by the fact that the hum was there only in Multi-channel LPCM and not when the sound track is bit streamed. A member of another forum explained to me that there is a difference in the sensibilty to grounds between those 2 modes in the electronics into a gear(!):dontknow:

Yesterday I thought that it also improved the quality of the SS&I when I listenned music played back by the BD-player and send into the receiver via the analogue RCA cable outputs. I thought that I was imaginating things. But, If I am not mistaken, cd music signal is in PCM then "translated" in electic signal into the player and then send to the rca outputs. Maybe this explains that. :dontknow:::sweat:


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## AudiocRaver (Jun 6, 2012)

You have made some real progress. Once you hear the difference, it is unmistakable.


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## FargateOne (Mar 3, 2015)

AudiocRaver said:


> (...) it is unmistakable.


That's it. I am most surprise.


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## Lumen (May 17, 2014)

AudiocRaver said:


> *THE LESSON:*
> 
> Check your noise floor! With no music running, and with streaming taking place, CAREFULLY crank up your volume level and see what you can hear at the LP and next to your tweeter.
> 
> ...


Re-awakening a recent thread for a late check-in:
Fascinating, and Kudos to you, sir! :T
Just when others think your system's max performance has been reached, you wring out another ounce. Reading through this topic reminded me to pay attention to both ambient and system noise floors. Thank you!


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