Why does the 1068/1095 Hum/Hiss

[bluesfan]

Demoed a 1068/1095 this morning.

Why does it hum/hiss from the speakers?

I notice other people have commented about this on audioreview.

Is this a feature of the brand or a fault like some loose earth?

An answer from Rotel would be nice.

Otherwise had some real grunt but is up against some stiff competition without HDMI and upscaling. Has put me right off.

Think Rotel is missing the boat at the moment.

[PewterTA]

You are going to get some amount of hiss from just about anything electrical... it's the nature of the beast so to say.

I have not had a single hum and the hiss can only be heard about an inch or two away from the tweater (with no other noise)... not bad in my opinion...

But there are some problems people have had with ground loop humming coming from the cable/sat feed that seems to cause issues for the 1068/1095.

Things seem to quiet down if you connect a wire from the external casing of the 1095 to the 1068...

Can't say exactly why that is though, so it could be a grounding issue from Rotel's side.

[bluesfan]

I don't quite agree. The Denon 3806 was quite as a mouse even at full volume using more or less the same wires and player.

If the shop can't get rid of the buzz how can a poor man like me.

If I have to spend alot of time correcting shielding problems it's a deal breaker for me good sound or not.

[soundhound]

The hiss may very well be component generated (pre or amp). I have not had a noise problem with any of my rotel pieces, all are or have been dead silent, or I would have taken them back to my dealer. Pewter is correct in his ground loop fix, as many pieces use different ground schemes, and if ground can be found throught the "signal path" it will. Ground loops are actually one piece of gear finding ground through another piece of gears ground, and when it pertains to audio gear, you hear it. In video, you may see it. Tie the chasis together via screws on the bottoms with a piece of wire, and your'e hum will dissapear.

[arrow]

well first question is what kinda speakers are you running the more efficent the more exaduarated any problem will sound. I have a yamaha and a rotel and i have hiss i have to accept it. Secondly my dad has a 30 year old marantz that back in the day did not have op amps that were so dead quit and there is a small level of hiss in the maranz he has. This is the joy of high current amps the amoung of hiss is the definition of a problem, if it is so loud u can hear it about 5 to 8 feet away then i would suggest investigating the ground loop issue but if as they have already said you can not hear it but right up on the tweater with your ear right on it, this is "Normal Operation" there will always be to some degree a hiss or humm in the speaker it is introduced threw the high current flow threw the transformer, wiht out haveing an autoformer like in a mchintosh or five seperate isolated power supplys some level of noise will escape the transforer, as stated before your dennon like my yamaha have operational amps instead of high current this is a completely diffrent kind of animale high current have a far better sound and a more full and punchy tone this is achived with higher current flows. Guys if i have missed somthing or gotten somthing wrong please jump in here. I wished sales people would explain the diffrence with moving from a reciver to a seperate the joys and the pitfalls it would help alot of people out wiht out having to pull there hair out over things that are not realy problems
As a side note i was in a demo room where a 30k marck levison was dead brand new peice of good dead so no not just rotel have issues it is just the state of affairs in production in genearl.

[Kevin D]

What he said ^^^^^^^. Hiss at volume, with nothing playing, 1-2 feet from the speaker is perfectly acceptable. Hum, clicks, hiss fom 5-6 feet is not.

Kevin D.

[tomm]

i get a hum coming from my 1068 and not from the speakers. is this a similar problem? on a dead quite night i can hear it from across the room.

[bluesfan]

i get a hum coming from my 1068 and not from the speakers. is this a similar problem? on a dead quite night i can hear it from across the room.

This is the problem. Some of us like to listen to quiet stereo such as piano. I think if you can here buzz across the room it is poor design from Rotel that there equipment is so susceptible to feedback noise. If other manufacturers can do it then Rotel should. The comment I heard on one thread that better equipment is more susceptible to feedback is just crap.

I'm sorry bur Rotel may sound good but there's a weakness somewhere in the design (even the 1067 buzzes).

Some people who have grounded units still have not got rid of it.

But is it the 1068 or the 1075/1095 or both? eg if I buy another make of processor will it go away or vs versa.

[H.Donald]

I own several Rotel products.Whether they are more likely to have hiss or humm problems is debatable.I once owned the 1075 amp and now have the 1095,along with a 1068 prosessor and rcd1072.
The 1075 was always very quiet,with only the hiss being the sound you get from all amps....you must put your head up to the tweeter to hear it.I switched over to the 1095...more power,different platform,more noise.I will admit that it is probably more sensitive than the 1075.It made me do things I should have done anyway,it really wanted it's own outlet...and it made me organize my cables.
At first there was significant buzz/humm coming thru my speakers....after trial and error I found that cleaning up my cleaning my cables,power cords separated from signal carriers,away from speaker cables....made the buzzing almost dissappear.I also gave it an outlet to it's own.It is now quiet as a mouse.
For some,plugging it into a power filter seems to work...all depends on the cause...

Also,I don't think you can compare a Denon receiver with a powerful amp...its just two different beasts.I also own a Denon 4802r,nice receiver but.........it is a not a power amp.

[bigburner]

Demoed a 1068/1095 this morning.

Why does it hum/hiss from the speakers?

See post #3 at http://www.htguide.com/forum/showthr...670#post206670

[bluesfan]

See post #3 at https://<br /> <br /> http://www.h...670#post206670

The Solution to My Problem

I solved my hum problem by getting my electrician to install a new dedicated 20 amp power cable from my switchboard to my listening room. All my hi-fi devices are plugged into this circuit, and I don’t use this circuit for anything else.

And how much did that cost - ridiculous idea! I think I'll just look for another make or if I do buy it accept that there will be buzz.

[Kens1]

bluesfan - I don't know what answer you are looking for. Some people don't experience the buzz/ hiss and some that do solve it by fixing ground loops or cabling.
Maybe you are better off buying the denon - since it is so quiet.

[Mark_C.]

Yeah, do us all a favor and buy the Denon.

Ground loop is almost inevitable once an outboard amp is introduced into the mix of audio-video gear. It takes patience to weed out the offender (usually ungrounded cable TV or satellite receiver) and rectify the situation. However, I think all here would agree that once the loop is eliminated, the move up to separates is well worth it.

[bigburner]

Originally Posted by bigburner

I solved my hum problem by getting my electrician to install a new dedicated 20 amp power cable from my switchboard to my listening room. All my hi-fi devices are plugged into this circuit, and I don’t use this circuit for anything else.

And how much did that cost - ridiculous idea! I think I'll just look for another make or if I do buy it accept that there will be buzz.

It cost me NZ$295 total which is about US$200. Compared to the cost of items such as power conditioners etc, plus all the hours I put in trying to solve the problem, I consider this to be an absolute bargain.

There are some very knowledgeable people in this forum. brucek is one of them. To dismiss brucek's advice as "ridiculous" is rather shortsighted of you bluesfan, not to mention taking a poke at someone (me) who has made the effort to help you out.

[Blazar]

I had a dedicated 20 amp line and it made no difference. Even with NOTHING else plugged into the wall or into the amp, I had significant hiss problems and could hear AM or FM radio (I'm not sure) through some of my channels... from my couch.

Having to deal with RF interference is absurd for something of this price range. The power output and overall sound were fine however.

[bigburner]

I had a dedicated 20 amp line and it made no difference. Even with NOTHING else plugged into the wall or into the amp, I had significant hiss problems and could hear AM or FM radio (I'm not sure) through some of my channels... from my couch.

I understand completely Blazar. I think that in my situation the dedicated line solved the problem because it put my sub on the same leg as all my other equipment. Being on the other side of the room I think that there was a potential difference between my sub and my preamp / 2 amps. Earlier, through a process of elimination, I had identified that my sub was the cause of the hum. Interestingly a cheater plug on the sub did not solve the problem.

I still have a small amount of hum that I would like to eliminate eventually. The next step will be to plant a new earth which will be dedicated to the standalone mains line. I live in an old house with old wiring so a poor earth is quite possible. I think that my electrician (a cool young guy who's quite intrigued by the whole hi-fi thing) will be able install the new earth for less than $100. Extravagent I know, but you only live once!

All EE opinions welcome.

[Elvis]

If you don't like Rotel hiss buy a Denon,thats a really great policy,glad I'm not a stock holder w/that slogan.Just fix the hiss Rotel.Oh,and the power supply hums on most units.You may own some speakers that don't reproduce all the signal and thus only hear minor hiss,sorry about your luck.I try to stay out of the hiss discussion as of late because its no use.Rotel policy must be to deny and hope their zealot defenders will convince the rest of the world its everything in the world BUT the Rotel.

[bluesfan]

I spoke to a guy at Rotel UK and yes, he basically said must of the complaints on HTguide were nonsense or weren't their equipment's fault.

If they bring out new models, they need to fix this obvious issue first before jumping in to adding HDMI, etc, especially at the premium price they have.

I am convinced this issue is a source of much shame and blame at Rotel headquarters and serves to demonstrate that hifi review magazines rarely tell you the whole truth.

100's of posts on this issue can't all be wrong.

[Kens1]

I beleive it's more common sense than a slogan. If you are so turned off by rotel products then don't buy it. Some hiss, some do not. Some people like Denon some hate it. If I was not satisfied with my Rotel gear I would give it up and move to something else. I wouldn't keep asking for answers to questions about quality I will never be satisfied with. I'm sure hundreds of posts can't be wrong either - so why even consider rotel? Why not just look at other brands that have no issues? Good luck with that endeavor.

[Kevin D]

Bluesfan,

What are your trying to accomplish here? Do some hiss? yes. Do some not hiss? yes. Do some hiss depending upon their location? yes. Could there be a solution to make them 100% silent? Yes. Is it worth Rotel to do this? no.

I install equipment everyday. I've had $299 Yamaha's to $8000 Mac pieces hiss/hum. A very high percentage of the time it's something else causing this hiss that might only surface with a particular piece (Rotel or otherwise). There's also what's acceptable, hiss within a 1-3 feet is fine and that's what 75% of the posts turn out to be. If you think it should be dead silent everywhere, buy something else.

Rotel does not have the same ability to test 100's of setups to find possible sources of interference. They're not designed to be run on crappy 30 year old power lines that a good majority of people have. They just can't keep the costs down that way. If you think of a triangle with low price,100% compatibility, and sound quality, the closer you get to two the farther you get from the third. Your Denon/Yamaha are the low price/100% compatibility kind. Your Bryston, Krell's are on the 100% compatibility/sound quality side. Rotel will be in the low price/sound quality side. If they went for 100% compatibility, the price would go up. If you want that now, there are plenty of companies out there in the next step up in price.

So Rotel offers excellent sound quality at a good price, but might have issues with certain setups. You can change your setup to help the situation, some changes (like dedicated power lines) could help the entire system as well.

If you decide to purchase Rotel, we will be glad to help you alleviate any issues you might run into. You could certainly return the units if we are unable to help. But as of right now, you have your answer. Some systems hiss, some don't. Until you have purchased your equipment and find an issue, please do not stir the pot pitting both sides against each other.

As far as 100's of posts, please get me a list of 100 users that have a hiss, still have the equipment, and have done everything possible to eliminate it. I will forward that information to Rotel. 100's of posts by less then 25 users is not a widespread problem.

I'm not taking sides on this one, the units are not silent in every situation due to a number of reasons (Rotel issues and system issues). If you do not wish to try different things to correct it, return the unit or live with it.

Any more posts turning this into a USER bashing or ROTEL bashing will result in the thread being locked. If you feel like saying something that goes against this, keep it to PM's.

Kevin D.

[ht_addict]

Bluesfan,

At one point I owned a Rotel 1095, and a NAD S250 and both amps hiss to a certain degree. Both also exhibited the dreaded groundloop hum that you could hear from the seating area. After a few hours off trouble shooting the issue, I determined it had to do with a number of issues.

1. Digital coax cables
2. Sub
3. TV cable.

I solved the issues by replacing the coax cables with optical, as well as running my tv cable through my power conditioner before running them into the tv. Problem solved.

[Elvis]

I just wanted to add to this thread.Many hum problems can be eliminated and have nothing to do w/Rotel.Its everyones obligation to make sure the issues are not their own,after that......As to Denon,all I ever owned were dead quiet and feature rich and were sonically inferior to Rotel in every way,imo.

[Bostonears]

More data points:

I bought an early unit of the 1067. The thing had a 60 Hz hum, evident from 8 feet away, even when nothing other than speakers were plugged into it. Therefore, it was not a ground loop. I returned the 1067 to the dealer. While there, we checked his demo unit, and sure enough, his had the same problem too. Apparently it was a defect in the first production run of the 1067. I ended up switching to a 1068 with a separate amp. (I understand Rotel has fixed the problem in later 1067s.)

The 1068 unit is dead quiet except when I have analog audio cables connected to it from my cable TV set top box. (I use an optical digital connection for normal cable TV audio, and only use the analog connections for a Tape Out.) With the analog cables connected, I get a 60 Hz hum out of the speakers, even when listening to the digital audio, and even when the cable TV coax is disconnected from the set top box. So this hum is apparently a ground loop between the set top box and the 1068. I'll be experimenting with an isolation transformer (such as this one http://www.jkaudio.com/pureformer.htm) to see if I can eliminate the hum.

[Kevin D]

I'd say it's 99% your cable coming into the house has a bad ground. It's not electrically connected with an optical cable so it doesn't hum. As soon as you share grounds you get hum. They make F-connector cable isolators, like this one:

http://www.jensen-transformers.com/datashts/vrd1ff.pdf

But you should be able to tell the cable company to come fix their problem.

Kevin D.

[Bostonears]

I'd say it's 99% your cable coming into the house has a bad ground.

As I mentioned in my previous post, I get the hum even when the cable TV coax is disconnected from the set top box, so that cable isn't the problem. The set top box is also connected to the 1068 by component video cables, in addition to the analog and digital audio cables. Apparently I'm getting a ground loop between the component video and the analog audio cables, but that seems odd, because when the cable TV coax is disconnected, the set top box isn't otherwise grounded.

[Markmm]

Looking at the back pannels, connecting the chasis of the 1068 to the 1095 might reduce the hum, as someone earlier mentioned, because the 1095 has a grounded plug and the 1068 doesn't. Why would they not ground the pre-amp? Seems like a simple cheap thing to do which appears to help.

[ht_addict]

As I mentioned in my previous post, I get the hum even when the cable TV coax is disconnected from the set top box, so that cable isn't the problem. The set top box is also connected to the 1068 by component video cables, in addition to the analog and digital audio cables. Apparently I'm getting a ground loop between the component video and the analog audio cables, but that seems odd, because when the cable TV coax is disconnected, the set top box isn't otherwise grounded.

Try running the TV coax through a power conditioner first if you have one then back to the set top box. Also try running you component cables straight to the tv rather than through the receiver.

[Bostonears]

Try running the TV coax through a power conditioner first if you have one then back to the set top box. Also try running you component cables straight to the tv rather than through the receiver.

In case I didn't make it clear enough in the two earlier posts, the hum I'm experiencing from my 1068 occurs EVEN WHEN THE CABLE TV COAX IS COMPLETELY DISCONNECTED FROM THE SYSTEM. Therefore, this problem is not related to the incoming cable TV coax, although apparently it is related to the cable set top box. The hum is audible whenever the analog audio cables are connected from the set top box to the 1068, even when I'm listening to other sources, so it's not simply a case of the set top box injecting hum into its analog audio signals.

When I have a chance, I'll experiment with moving the component video cables to see if it affects the hum, although that is not a long term solution for me. One of the main reasons I chose the 1068 is that it has component video switching. I have three devices that output component video, and running component video cables from the set top box straight to the TV defeats one of my configuration requirements.

[RobP]

The hum is audible whenever the analog audio cables are connected from the set top box to the 1068, even when I'm listening to other sources, so it's not simply a case of the set top box injecting hum into its analog audio signals.

It sounds like you have a nice groundloop problem, you may want to get a pair of cables that have a ground lead attached and ground it to see if that cures your problem.

[ht_addict]

In case I didn't make it clear enough in the two earlier posts, the hum I'm experiencing from my 1068 occurs EVEN WHEN THE CABLE TV COAX IS COMPLETELY DISCONNECTED FROM THE SYSTEM. Therefore, this problem is not related to the incoming cable TV coax, although apparently it is related to the cable set top box. The hum is audible whenever the analog audio cables are connected from the set top box to the 1068, even when I'm listening to other sources, so it's not simply a case of the set top box injecting hum into its analog audio signals.

When I have a chance, I'll experiment with moving the component video cables to see if it affects the hum, although that is not a long term solution for me. One of the main reasons I chose the 1068 is that it has component video switching. I have three devices that output component video, and running component video cables from the set top box straight to the TV defeats one of my configuration requirements.

In case I didn't make it clear myself, have you tried running your coax cable through a power conditioner before going to the tv. Give it a shot, it may actually ground your setup and remove the noise. It did for me when I had the same problem your having. Have you tried any off the suggestion people have given you? Only trying to help.

[Bostonears]

In case I didn't make it clear myself, have you tried running your coax cable through a power conditioner before going to the tv. Give it a shot, it may actually ground your setup and remove the noise. It did for me when I had the same problem your having.

Now I see what you are suggesting, which is not that the coax cable is the cause of a grounding problem, but that it might be able to solve the problem by providing an alternate ground. Unfortunately, the very first set up I tried had the cable TV coax running through a very nice power conditioner, and the hum problem was present. So the coax cable neither causes nor fixes the problem.

After much experimentation, I finally determined that the problem was a rather complex ground loop involving the cable set top box, my DVD recorder, and the 1068. The DVD recorder never had anything connected to its coax input. (All the recording is done with input from the cable set top box.) Both the cable set top box and the DVD recorder are connected to the 1068 by both analog audio and component video cables. (They are both also connected to the 1068 by optical digital audio cables, but that is not relevant to the hum problem.) If one or more of the analog audio or component video cables was connected to the set top box AND if one or more of the analog audio or component video cables was connected to the DVD recorder, I got hum. Also, if either the set top box or the DVD recorder was completely disconnected from the system, and if the remaining device had both its analog audio AND its component video cables connected to the 1068, I got hum. So I was getting ground loops both between the two devices and between each device and the 1068. (Don't ask me how it was happening, but that was the case.) Running separate ground wires from each device to the 1068 and/or the power conditioner did not solve the problem. If anything, it made it worse. The solution was to put a ground loop isolator on either the analog audio or the component video of each device. Since analog audio ground loop isolators are a lot cheaper and easier to find than component video ground loop isolators, I picked up a couple of the audio ones at Radio Shack, and now the hum is gone. It's not an ideal solution, but it does work.

[csuzor]

This article is excellent on this topic. http://www.smr-home-theatre.org/Ground-Loops/

In a nutshell, hums are mainly caused different ground connections, as typically found with cable video equipment, or having multiple power outlets to av gear (use only 1 if you can). Adding ground loop isolators (which basically make an electromagnetic connection between 2 wires, instead of an electrical connection) removes the hum, and can be used between equipment, or on the incoming cable video line. Otherwise, you could ground the cable tv line locally!

I am afraid that putting a ground loop isolator on an audio line may seriously degrade the signal (especially high frequencies), but I can't confirm that.

Other common sources of noise are light dimmers, miswired powered outlets, lost safety ground (I had this one in part of the house, took me 2 years to find it!).

Worth reading imo.

[Bostonears]

I am afraid that putting a ground loop isolator on an audio line may seriously degrade the signal (especially high frequencies), but I can't confirm that.

I haven't (yet) noticed any degradation using the ground loop isolators, but in my system, the analog audio outputs are mostly used to drive a set of remote speakers in the kitchen. They're decent speakers (Cambridge SoundWorks) but not outstanding. The primary audio in the living room is run off the digital audio outputs, with an outstanding set of speakers (Sonus Faber). For my situation, sacrificing a minuscule bit of quality in the remote speakers would be well worth eliminating the evident hum in the primary speakers.

My cumbersome configuration is necessitated by the fact that the Rotel 1068 will not convert digital audio inputs to line level analog audio outputs. If the 1068 had this fairly simple feature, I could have eliminated a bunch of analog cables in my system, and the hum never would have existed.

[quandosai]

All I can Say is Thanks!

Guys,

I am new to this forum but love my Rotel gear. I recommend it to all of my friends and have built several home theater setups for buddies using Rotel.

I want to send out a THANK YOU to all of you who have provided some insight into this problem. I have an RSP-1066 connected to an RMB-1095. I recently moved into a new house. Before I moved, everything worked fine. After moving, everything still worked fine. Then, all of a sudden, a nasty buzz started coming from my analog inputs. If any analog input was plugged into the RSP-1066, a loud buzzing occured. It was loud enough to even hear outside of the room.

I called Rotel. They had me send the unit in. Of course, they could not duplicate the problem but sent me a new (B-stock) unit just for good measure because I tried everything I could think of to troubleshoot the thing on site (including trying another RSP-1066 that a buddy of mine had--which I have to add worked!). I got my new 1066 from Rotel about 2 weeks ago, plugged it in, and the same thing.

Finally, the other day, I started searching online for a solution. I immediately found this forum and thread. It made me start thinking.... The problem started after the cable guy came (new construction house) and installed the cable. The room that I turned into the theater room did not already have a cable drop, so he had to install a new one. Apparently, he did not ground it properly.

So, today, I disconnected all of my HD cable boxes, and voila, the buzz went away. I then took the cable from the cable outlet and tied it through by Monster Power Center and then back to the HD set top box and reconnected all of my cable connections. No buzz.

Simply amazing how stupid things like this can drive a person crazy!

Again, thanks to all of you for the many suggestions to others that I was able to use and solve my problem.

Regards,
Jared

[chinets]

I have Rotel 1098/1095 combo and NEVER had a hiss or hum. Select Dennon if you hate Rotel, but believe me have a technical problem somewhere because you can't hit on Rotel when most people who have Rotel have never ever complained of what you are experiencing. I am sure it has to do with looping or some manufacturer defect because ROTEL is as quiet as a door mouse all the time. Good Luck and I am sorry this happened to you which really is a freak incident IMHO !!!