Is My Panasonic Tuner/Amp Defective?

[dory]

Hi,

I have a problem with what appears to be my Panasonic SA-XR25 Receiver/Amplifier I purchased about a month ago. It has a one year labor and parts warranty, so i'm not too concerned, but i'd just like to know if it's definitely defective. I know someone here will know after I give the symptoms so here it goes.

I noticed when I'm watching a DVD movie the center channel speaker goes off when the volume is set too "high" loud on my amp. The amp has DB's from -76 to 0 and when watching an action movie, I usually set the Amp to a very loud -12. Once this started to happen It happened rarely so it was tough to figure out what was going on. I checked my connections on my speakers and on my amp and all was fine but I re-did them just in case. Still had the same problem though. So today when it happened I spent about 2 solid hours unhooking all my speakesr INCLUDING the subwoofer, and just left the Center speaker hooked up.

I then put the volume at -12 and put the movie "BLADE" in because it has a lot of action and club scenes at the beginning. Sure enough, as soon as it got to the part where the one woman vampire says "Is there a problem baby" the Center channel cut off. I said hummmm, so I went up to a lower volume of -16 and replayed that part and it was perfect! I tried again at -12 and sure enough, it cut off. So now i'm thinking my Center speaker isn't powerful enough but when I checked the manual my Center speaker is capable of 175 Watts, my Amp is 100w x 6, so I figured that wouldn't affect it.

But then I decided to go ahead and unhook my actual center speaker and plug in one of my Front speakers and try this again. To my surprise, sure enough, at -12 the speaker cut right off at the same, exact spot! My Front speakers have a max capacity of 250W so I was pretty sure it definitely wasn't the speakers, especially when my older receiver didn't cause any speakers to cut off at any level.

What is interesting here is that my amp never cuts off when watching a movie or T.V at a normal level, but at a very loud level the Amp cuts off that center channel. Does that seem like a definite defect in the Amp, or could it be something else? I'm definitely ready to take this in for repair on Monday, but if someone that knows better thinks the Amp is fine and it may be something else, please let me know. Being that the nearest repair center is about 30 minutes away from me, it would be a huge help if it could be something else, but I can't think of what else it could be other then the Amp having some kind of defect. If anyone has any suggestions or advice, please let me know.

Thank you much in advance.

[Kurt S]

Yes, it sounds like the amp is defective. Good amplifiers have overload protection in them to keep them from overheating or clipping the output to the speakers. It's possible the protection circuit is cutting out to early.

Another factor could be that your using a speaker with a lower impedance than the amplifier is comfortable with. Check the specs of the amplifier for the impedance range it is happy with and compare the to the impedance of the speaker you are connecting to it.

[dory]

hey Kurt S, thank you so much. Well, I actually took the Amp into an authorized Panasonic repair center this morning as it's under warranty for parts and labor for 1 year and it's only been a little more then a month. So I guess we'll see what they say needs fixing but the place wouldn't allow a customer to speak with a technician as they're too busy they said so I coudln't explain the problem to a technician, I just made sure the person at the counter put the problem in detail in the computer.


I am a little ignorant with this stuff so when you say Impedence, I guess you mean OHMS, right? I think 8 OHMS is the most common from what i've read and all my speakers are 8 ohms. I just checked my amp manual and it says for front, center and surround speakers 6-8 ohms, so my speakers should be fine with that, right?

It looks like the problem is what you said first maybe, because the interesting thing is that no matter how loud I turn the amp up, none of the other speakers cut off, not the front or the surround, only the Center speaker.

Just one other question for you, if the protection circuit is cutting out too early, would it be possible for the front and surround/rear speakers as well as subwoofer to stay on without cutting out but "only" the center speaker actually be cutting out too quickly? If so, then hopefully that's the culprit and the technicians fix it.

One thing to note which I find kind of interesting is that as soon as the center speaker cuts off, if I immediately push "stop" on my DVD player to stop the movie, then quickly press start again, the Center speaker is right back on along with the rest of the speakers. For example, if I am watching a movie and the center speaker cuts off and I do nothing, the center speaker stays off, even if I turn the volume down on the amp. But if the center speaker goes off and I stop the movie and push play, even within' one second, the center speaker is back on and working.

Does that seem weird?

Thanks again for your time and help.

[Kurt S]

Yes, by impedance I mean ohms. Your amplifier can handle an impedance load of 6 to 8 ohms. Now check what the impedance of the speaker is. It should give the specs on the back of the speaker such as power handling capabilities and the impedance. Make sure it says it is in the 6 to 8 ohm range. If it says something like 4 ohms, that is to low for your amplifier and could be the reason it's cutting out.


Depending on how the protection circuit is built, it is possible for it to cut out on the center speaker without affecting the rest of them.

It is interesting that stoping the DVD player for a brief moment causes the center speaker to work again. Usually the circuit protection is on a short time delay and will switch itself back on after a few seconds. I don't want to do to much speculating yet though. Best to wait and see what the technicians find out.

Again though, check the impedance of the center channel speaker. Make sure it is in the 6 to 8 ohm range and not a lower value such as 4 ohms.

[dory]

wow, that was a quick reply, thanks again!

I just checked the back of my center speaker and sure enough it is "8 OHMS" It says System Impedance: 8 OHMS. My front and surround speakers are also 8 OHMS. So I guess that rules out that problem, huh?

I am obviously no expert on this but you sound like you may be, but even for someone like me with little knowledge on this, I also thought it was really odd immediately stopping the movie and playing it again would allow the Center speaker to turn back on so quickly, because my old Receiver cut off once or twice when I really turned up the power once just to test my speakers and I heard a click and the power shut off to "all" channels/speakers. About 15 seconds or so later they all came back on. That receiver wasn't as good as this one, so i'm guessing that circuit overload thing you were talking about had something to do with that situation with my old receiver as well.

Is it possible that the way this panasonic is set up that maybe once an overload to say the Center Channel occurs and it cuts off, that the panasonic is set up to turn back on when no power is going through the amp, such as when I turn the movie off by stopping it, but then quickly play it again?

What do you think now? Either way, i'll let you know what the Technician says when they call me. They say it could be 5-10 days before they're able to notify me and tell me what the problem is, and if they need parts it could take a month or longer before I get my amp back, that stinks. lol

[Kurt S]

Hi Dory, Well it does sound like it's the cicuit protection kicking in.

Let me ask you a little about your setup. Do you have a full 5.1 speaker setup? And if so, how was the audio setup when you were watching the movie? In other words, were you watching it with a Dolby digital or DTS 5.1 audio going to your reciever or was the movie in stereo and your reciever decoding it to a Dolby Pro-Logic pseudo surround?

The reason for asking is a ran into a little issue when I put my center channel in my system. With a true surround signal, bass will be outputed to your subwoofer. With a Dolby Pro-Logic mix, most of the bass will be put in the center channel if you don't have a subwoofer. This can eat up power real fast to your center channel and be very hard on a small center channel speakers.

[dory]

hey again Kurt S, thanks once again for your assistance.

O.K, I have a "full" 5.1 Dolby Digital Surround system. I have 5 speakers plus my subwoofer for a total of 6 speakers. The Center speaker is a medium to large sized JBL. My amp is capable of DTS decoding as well so I can watch any movie with dolby digital or DTS. When this issue has occured with the center speaker cutting off it's always been with a Dolby Digital 5.1 movie. I'm guessing it would occur with DTS too but I don't have that many DTS movies so I rarely use DTS.

Do you think any of this helps identify the problem? My only concern now is an incompetant repair technician. I've only had to take a couple of electronics items in that i've owned and one time It took six weeks to get a VCR fixed and I had the same issues when I got it back. Now VCR's are so cheap i'd just buy another one if mine was broken and not covered under warranty but i'm hoping I don't have the same problem with this Panasonic amp.

If you still think it's the circuit protection, is that a big job and would they have to wait on a lot of parts from Panasonic? Or is that something they should have readily available in terms of parts? If I had to pay out of my pocket, which fortunately I don't, how much would a job like that cost?

Thanks again in advance Kurt.

[Kurt S]

Ok since you are listening to a true 5.1 surorund signal the bass output will be going to the proper speaker.

And you are running this signal through a optical or digital connection from the DVD player to your reciever, correct?

As far as the price or complexity of replacing the bad part, that's impossible to say. But yes, I still am leaning towards it being something in the circuit proection.

[dory]

hello once again Hurt. Well, yep, you are correct again, i'm using an Optical cable which goes directly from my DVD PLAYER to my AMP. I like the fact that it's just one cable, and a pretty thin cable and that's supposed to give the best sound quality from what i've read too so it works out well for me.

Still think it's the circuit protection or do you think maybe the Optical cable has some kind of issue? The only reason I didn't think it was the optical cable was because of how I told you I can stop the movie then play it again right away and it plays fine. But what do I know, right? That's why i'm askin'.

[Kurt S]

Nope, not the optical cable. They either work or they don't. Yup, I still believe it's the circuit protection.

[dory]

Kurt S, I hope you are still around to give your suggestions or advice on this.

Here's what happened and it doesn't surprise me in the least bit. The short version is that I was called by the lady who checked in my amp and she said the unit was ready for pick-up. I asked her what was wrong with it and she said the technician said the unit was perfectly fine. I almost expected something like that to happen and i'll tell you why.

When I dropped the unit off with the girl she asked me what was wrong with it so she could write a description to the tech. I told her the center speaker cuts off completely when the volume is up louder then minus 12 db's. She said, oh, ok, we'll call you. I asked her if I could read what she wrote to the techs and she said o.k.

When I read what she wrote I said to myself you've got to be kidding. She wrote when the unit is on all the speakers just turn off every so often. I looked at her and kindly said that it was the center speaker and it only cuts off when the volume is too loud, specifically over -12 db. She said, oh, ok, i'll write that in.

So I asked her to read what she wrote after she did that and it said this. 'SINTER' speaker cuts out over -12 DB's. Spelling center the way I did. I just said 'oh boy' to myself and figured that would be enough for the tech to identify and solve the problem but this place seemed very incompetant for a few reasons those are just a couple.

Anyway i'm going to pick up the unit with the same problem I had before what do you suggest I do? The next nearest repair center is 40 miles away. Can I have Panasonic do anything about this as I still have 11 months left of a 12 month warranty? What do you suggest?

[Kurt S]

I feel your pain. When I purchased my surround system, the left channel would clip if I really cranked it up. Long story short, I had to hook up an oscilloscope to the amp to prove to the folks at the stereo store there was something wrong. They put me in touch with the Dennon rep and after a very intelligent discussion with him they gave me a new amp.

I suggest you do the same. If you purchased your reciever from a stereo store, have them give you the name of the local Panasonic rep in your area. If they can't or won't provide you with at info, go online to Panasonics website and explain the issue to them. The reps are usually very nice and will work with you to resolve this issue.

You might also have a little chat with the manager of the store. You payed good money for that amp and if the lady who recieved your equipment can't even spell or take the simplest of instructions, you have the right to speak to a technician. Don't let them push you around.

[dory]

hey Kurt, glad you are still around. I'm going to follow your advice and i'll let you know what happens. Interesting you had a similar issue. You know, besides them being incompetant, it's apparently impossible to speak to a tech at this place. I asked the girl if I could speak to the tech on a couple of occasions and she said 'no, they don't talk to the customers.' From what she said I came to the conclusion that it would be easier to talk to Aliens from a different Solar System then it would be to these people.

Panasonic really frustrated me as they continued to give me the runaround on what the issue was and had me test things that seemed nowhere related to my issue before they said I should take it in to a repair center. I think it's reasonable to go through potential causes but they had me going through resetting the unit on a couple of different occasions when I told them that didn't help. They also had me do other troubleshooting which i'm pretty certain had nothing to do with this issue although I could be wrong as I'm not expert. But having me run surrond tests on all my speakers, etc. is just an example.

I'm gonna do what you said next week, and i'll let you know what happens. I appreciate all of your advice. Thank you.

[dory]

well Kurt S, if you are still checkin' out this forum and this post here is the latest. I went into the place to get my receiver today only to have them tell me it was perfectly fine still. I told them that I tried this issue with
different speakers with the same results. I had actually brought my center speaker with me. The technician hooked it up and the problem occurred right in front of him. He was surprised as he hadn't seen that issue before but he told me that the speaker was the problem not the tuner. He said the tuner was in perfect shape and he checked everything out twice. I then explained why my front speaker did the same, exact thing and he said he wasn't sure but it was the speakers.

I really didn't buy that but he started checking stuff and hooked up some metal type object with wires to my speaker and my JBL N series center speaker showed something like 5.3 OHMS when it is supposed to have 8 OHMS. So he then connected another type of device which apparently "ADDS" OHMS to the speaker and then we tried to duplicate the issue and the tuner was perfectly fine as was the speaker. The issue would not repeat! So now it really looked like the speaker and I asked him how this could happen and he said something about over time the coil gets worn inside the speaker with the heat, etc,, stuff i'm not all that familiar with. Anyway, I still wasn't fully sold on the speaker because my other home front speaker did it and that's an entirely different brand. So I decided to purchase a "KLIPSCH" center speaker from Best Buy and try it out. It was a good price and it's apparently a good center speaker from what I was told. I hooked it up and turned up the volume and the speaker and tuner played perfectly! I was pretty shocked but now I know it was the speaker as the technician said.

I just find it really odd that my other front home speakers which are Cerwin Vega have the same problem and those are fairly new. My JBL is about 3 years old, but it has a 5 year warranty. So really I am thinking I'll try to get JBL to repair or replace the speaker under the conditions of their warranty and if that doesn't work i'll keep the Klipsch center speaker. What do you think?

And if you are familiar with how a speaker could "lose" OHMS like my JBL apparently has, and don't mind explaining to me how that's possible, that would really be helpful. The tech was talking in technical terms and I didn't want to take up more of his time so I just thanked him and left. But I just didn't realize a speaker could go from 8 OHMS down to 5 OHMS like mine has, is this normal?

Well, I guess i'll call JBL tomorrow, do you think they'll be any reason why they wouldn't honor their Warranty?

Thanks again in advance Kurt.