Hi...I'm new to the site and I have a question. I have a Marantz SR7400 home theater receiver. I've had the thing for over 3 years and have enjoyed fantastic sound without a problem, but over the past few months, I'm getting an annoying buzzing sound coming from the left channel speaker even when the volume is on the lowest setting. I'll explain the steps I've taken to isolate the problem to cut to the chase. I've unplugged every component (cd, cable box, tv, etc) from the receiver and the noise persists even when the receiver is plugged into the wall with nothing attached to it other than a pair of headphones! The buzzing is generally in the left ear. I've tried using different pairs of speakers, different headphones and have even moved the receiver to different places in my house, at times plugged directly into the wall and at other times plugged into a power strip. The buzz persists. Interestingly, I have a newer Marantz 5000 series receiver in another location in my house and it's perfectly quiet with the same headphones and speakers. I had an idea to use the newer Marantz' ac cord with the sr7400 but the buzz was still there. I finally broke down and brought it to an authorized Marantz repair shop and although the guy heard the buzz through the headphones when I first brought it in, he said that none of his technicians could replicate the buzz over the next two weeks with their speakers or headphones so there was nothing they could fix. I brought it home, plugged it in and the buzz was immediately audible again. I'm really dumbfounded as to what i can do here. Any thoughts?
The Marantz repair shop didn't give you any suggestions when you picked up the unit? I do hope their service was no charge.
The problem here is there are so many possible causes for an intermittent hum or buzz in a HT receiver. The first place to consider is always capacitors and they can be quite bothersome when it comes to being intermittent, seeming to heal themself whenever the technician is looking. Other common cause for noises would be cold solder joints that are "made" when the unit is lifted and carried from one place to another and "unmade" in similar fashion. I assume you have some idea just how many capacitors and solder joints exist in a HT receiver.
If the service shop heard the problem at all in their location, then you have an answer that says the issue is not in your system set up. If the problem moves with the receiver, it is in the receiver.
There's really nothing that can be done over a forum for such problems. They are at the mercy of a tech and all techs are paid by the individual repair not by the hour so no tech has the luxury of siting in front of a functioning component waiting for it to make bad noises. A company the size of Marantz will have master techs at regional service centers, these are usually the best techs who have a knack for tracing problems and repairing dogs. It's possible your unit might need to visit one of these shops.
The only suggestion to give right now is call the Marantz shop back and get their advice. They know the protocol for sending units to the regional shops and they can advise you whether you should take the next step or have the local people take another look. Either way, a technician cannot repair what does not appear to be broken. There's no guarantee the regional shop will have a receiver that is making noise or working perfectly.
Call the local shop and go from there. You don't want to hear it but you're a long way from being totally frustrated by a HT receiver.
Jan, thanks for responding. They charged me a $10 "bench fee" to diagnose the problem which I couldn't argue with. They had my unit for 4 weeks and the owner (who took the unit from me in the first place) indicated that they kept it on for several hours a day with several different techs listening and NONE could hear the buzzing, even though he (the owner) himself said that he clearly heard it through my headphones when I dropped it off. The guy was rude and offered no suggestions. To top it off, he claims that I didn't give him the a/c cord when I dropped it off so he returned the unit to me without one. After an argument, he agreed to just give me one from his shop, however this one has 3-prongs (that go in the outlet) whereas mine was a 2-prong. Also, the back of the marantz has 2-prongs and this cord has 3 slots. He said it doesn't matter. Does it? I'm going to call Marantz and describe my experience and see if there is a "master" technician they can recommend in my area. I live 20 miles from New York City so I'm guessing there must be one nearby.
No, in this case the number of "slots" doesn't matter on a power cord as long as it fits snuggly and gets the AC where it needs to go. The rude/friendly factor at the desk is no indication of the quality of techs behind the bench. I've worked with several techs who were top notch (one being the regional service tech for several major players) but getting the gear to them could be less pleasant than a root canal depending on who walked up to the desk. You'll rarely get to see a tech nowdays, they are getting paid when they are fixing equipment and they loose money if they interact with customers who can get very chatty and keep the from doing their real job.
I'm going to call marantz. Some guy on another blog mentioned something about "grounding." I've always just plugged the receiver in and made all the other connections (tv, cd player, etc..). I've never used an extra grounding wire or ground loop inhibitor for the receiver. Do these things do anything? One guy said that the 3- prong a/c cord might even help?!
The receiver is grounded through the AC cord to the wall outlet which is grounded to the service panel which, by law, should be grounded to a literal earth ground. The three pin cable is only worthwhile when there is a three pin outlet on the component. Using a three pin cable with a two pin connector doesn't provide any benefits not found in a two pin cable.
The third wire in a three pin system is a dedicated ground wire and it "lifts" the chassis ground of the component from the two (hot and neutral) "live" conductors. This is a superior method of grounding but it is not a reliable system when used in a typical audio system. Audio manufacturers have yet to adopt a consistent grounding system for their components with some components using a two pin system and some a three pin system. With such a mix of ground planes throughout the system all tied together by the interconnects which make the individual pieces a working system there can often times be more problems introduced when one component uses the three pin system while the rest have only two pins for everything.
Consumer audio has for decades labored under poor ideas hatched in the age of convenience and cheap to build products that constantly plague it with noises and other assorted ghosts that were long ago banished from the pro audio side of the business. Many of these problems are the result of dumbed down thinking on the part of the consumer audio industry itself and much of it is due to the fact consumers are slow to adopt better products when cheaper and more convenient is what they really want.
Your system, according to what you posted, doesn't have a problem with two pin/three pin issues. First, you only have a three pin cable but not three pins at the receiver connection. That makes your receiver a two pin system no matter what cable you use. That would then be the same system you've been using since the day you purchased this reciever. Unless the noise has been there since the day you installed the receiver, the two/three pin cable answer is not relevant to your problem.
Second, the noise travelled with the receiver when you took it to the shop. Unless the guy at the counter was not telling the truth - and there's no reason to think he was not, he heard the noise at another location and without any other components connected to the receiver. This would indicate a problem that exists within the receiver and not within your AC wiring at your home.
Do take a moment to realize there are "coincidental" ocurrences which allow two problems to co-exist at the same time. This means I'm not ruling out potential problems with the wiring in your home but I'm saying this doesn't appear to be the cause of this particular problem.
Those two reasonings should eliminate AC "grounding" as your problem for right now. The new cable has nothing to do with causing or solving the problem. It exists, if what you've reported is factual, within your receiver.
Possibly the person who threw out "grounding" as a possible cause of your noise meant component grounding within the system. This is a common issue when noises appear over time or when changes occur within a system. However, this wouldn't appear to be the case with your receiver. The first test for system induced noises, particularly those created by interconnection problems, is to remove all other components from the receiver. In your op you state this was your test and the receiver failed the test. The noise remained when no other components other than headphones were connected. Most modern receivers do not power the headphone jack off the main output transistors, instead they use an ic based headphone amp which is placed before the power amp section of the receiver. This further isolates the issue to the receiver and then only to a few sections of the receiver. Unfortunately, one of those sections likely to fail is the power supply which feeds voltage and current to the rest of the receiver's circuitry. None the less, there are still hundreds of solder connections within any small portion of the receiver which could be causing your noise. There are numerous capacitors that could have failed or are about to fail along with dozens of ic's which all function as hundreds, if not thousands, of discrete components. Any of these could be the source of your noise.
I hope you understand the complexity of chasing down a simple noise that disappears when the receiver is transported to the shop. It is not at all uncommon for such problems to "heal themself" any more than it is for the noise to disappear once the mechanic rasies the hood of your car. That is life in a modern technological age.
One issue you should resolve before you contact another shop or the same shop is how the noise began. Did it suddenly appear one day? Did anything in the system or in the house that might be related electrically to the system change just before the noise showed up? Did the noise become obvious over time? Did you notice it getting worse over a few days or weeks? Does the noise go away or become worse when you are using a particular function of the receiver, such as Dolby Surround vs. simple stereo. Is there anything you can point to that makes the noise more or less evient? Or, is the noise just there no matter what?
Providing answers to these questions will assist in the tracking down of areas where the potential problem might exist. "Potential" and "might" leave a lot of room for still not finding the cause of such noises. They can be elusive and frustrating to all involved. Even when one issue seems to resolve the noise issue, another problem area can result in just another noise causing yet another problem.
Sometimes these intermittent issues result in the owner finally giving up after a period of months without resolution and without a working receiver. At that point the best solution is to cut your losses and move on. No product is perfect and even the best and most expensive lines have service departments for just that reason. A manufacturer can buy a swith that is tested over 5,000 times and yet on the 5,053rd time it will fail. Things fail. The most you can do is research which manufacturers have the best reliability record and the best customer service history. Then decide between a select few which company has the product you like and can afford. Frustrations abound in the consumer audio market but overall frustrations with mass market equipment did their part in fueling the high end market of better sounding and more reliable products - which come at higher intial cost. Everything in this business is a trade off of something for something else. Consider that right now, even if your receiver were working properly, it's resale value is near zero because the market has moved on.
HT receivers are becoming more and more a disposable commodity. They age far beyond the average component would have in the 1960-70's. My friend the regional service tech finally reached an age and a mindset that convinced him fixing the stuff being produced for the mass market wasn't worth his headaches.
You'll have to decide how far to pursue this issue with your receiver and when frustration and cost are no longer worth your effort. Unfortunately, at three years of age, your HT receiver is considered nearly obsolete by the industry that produced it. Their aim is to sell new gear, not to repair old gear. Customer service is only as important as any one company wishes to make it. For the most part, Marantz has a better than average score on customer service over the last few years so you do have that going for you.
You'll have to decide for yourself when this becomes more trouble than it's worth. Sometimes a tech gets lucky and the problem makes itself apparent quickly and one trip resolves all the issues. Sometimes not. But at this point there would not appear to be anything you can do about this other than contact Marantz and proceed under their guidance. They are the people who should know their product and its common failures the best. After that, you'll just need to make some decisions.
Wow! Thanks for taking the tlme to give me all the detais and complexities inherent in my buzzing issue. To clarify, the noise just came on one day...in fact my wife noticed it before I did. A movie we were watching ended, I turned off the DVD player and she said "what's that buzzing noise.?"...and so it began. When you listen to music or voice, you only really hear it faintly during quiet parts in the music or dialogue. I should tell you that your assessmet of the industry is spot on. Before I brought it to an authorized marantz dealer, I took it to a local audio/video repair guy who I've used 100 times for other av components. He took one look at it and said that whatever it was, it was likely going to cost me $200-300 given the time it would take to hunt the problem down. Maybe I should just learn to live with it. I'm not dropping another $700 for avreceiver so fast. should also tell you that after our discussion earlier, I contacted marantz and the gave me the name of their preferred shop in the NYC area. It's 75 miles away but if the home office is recommending it I suppose that's a good start. I'll write you again if there are other developments.
Living with an issue like this is probably not the best idea. The buzz won't go away by itself unless some external condition which is the cause of the problem changes. If the problem is internal to the receiver than it will probably get worse over time and may result in some kind of catastrophic failure..... some big ZAP followed by unpleasantness. The Marantz specialist might have seen this before, but it is a generic enough problem to have several potential causes. Personally, I'd get it fixed and be good for another few years. Jan's right. HT stuff changes pretty quickly and your receiver is no longer state of the art. But, for a small additional investment you are good for another few years. If it breaks again (soon) after a fix, drill a hole in the top, fill it with Plaster of Paris and donate it to an artificial reef. Than replace it. Start saving now.